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Kant’s Dynamic Constructions

Kenneth R. Westphal

The definitive version of this article appears in:

Journal of Philosophical Research 20 (1995):381–429.*

ABSTRACT. According to Kant, justifying the application of mathematics to objectsin natural science requires metaphysically constructing the concept of matter. Kantdevelops these constructions in the Metaphysical Foundations of Natural Science(MAdN). Kant’s specific aim is to develop a dynamic theory of matter to replacecorpuscular theory. In his Preface Kant claims completely to exhaust themetaphysical doctrine of body, but in the General Remark to MAdN ch. 2,“Dynamics,” Kant admits that once matter is reconceived as basic forces, it is nolonger possible to construct the concept of matter. I argue that Kant’s admissionis only the tip of the problem, and that none of Kant’s commentators has fullygrasped the problems infecting the MAdN that underlie Kant’s admission. I showthat Kant’s proof that matter consists of forces is fallacious. I then re-analyze thecircularity in Kant’s definition of density, criticizing both Adickes’ formulationsand later dissolution of it. I also show that a third circularity infects the relationsbetween Kant’s treatment of “Dynamics” and “Mechanics” (MAdN ch. 3). Thesethree fundamental problems demonstrate the untenability of Kant’s metaphysicalmethod, and they require the radical revision of the relation between mathematicsand metaphysics Kant undertakes in his opus postumum. I show that some of Kant’smost surprising and critical later claims about the Critical philosophy are correct,and that they require the sorts of remedies Kant contemplates in the opus postumum.(I defend the essentially correct analyses offered by Burkhard Tuschling and EckartFörster against criticisms by Michael Friedman.)

I. INTRODUCTION.

According to Kant, natural science can be properly scientific only to the extent towhich it applies mathematics to its objects. However, the possibility1

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of applying mathematics to objects in natural science presupposes principles for theconstruction of the concepts which belong to the possibility of matter in general.2

Hence a complete analysis of the concept of matter in general is the basis of naturalscience, and this analysis is provided by pure philosophy. The official aim of Kant’s3

Metaphysische Anfangsgründe der Naturwissenschaft (‘Metaphysical Foundations of NaturalScience’; hereafter MAdN) is to provide metaphysical constructions, together withthe principles of these constructions, as a distinct discipline which explains andjustifies the possibility of mathematical physics.4

Kant’s more specific aim in the MAdN is to develop a dynamic theory of matterto replace the corpuscular theory of matter. To do this, Kant must develop the mainconcepts needed to formulate a dynamic theory of matter, and he must show thatthe resultant theory provides an adequate, if not a superior, basis for Newtonianphysics and for scientific research generally. Moreover, to propound such a theoryas a philosopher, in particular, as a Critical philosopher, Kant must link his theoryof matter with the main tenets of the first Critique, and he must develop his theoryof matter within the constraints of the metaphysical method set out in the MAdN.5

Unlike other sciences, Kant says one can expect completeness in metaphysicsbecause it is based on the fundamental laws of thought, where the Table ofCategories of the first Critique provides the schema for determining that complete-ness. In his Preface Kant optimistically claims to have completely exhausted the6

metaphysical doctrine of body, though he modestly admits that this is not a largeaccomplishment. In view of these claims it is startling to find Kant admitting, in the7

General Remark to “Dynamics” (the second chapter of the MAdN), that oncematter is reconceived, not as corpuscles, but as basic forces, it is no longer possibleto construct the concept of matter, and to find Kant making suggestions to guide8

the development of the requisite constructions.9

This tension, if not contradiction, has generated significant, on-going discussion.After briefly reviewing this discussion (§II), I argue that Kant’s admission in theGeneral Remark is only the tip of the problem, and that none of Kant’s commenta-tors has fully grasped the fundamental problems infecting the MAdN that underlieKant’s admission in the General Remark. Understanding these deeper problems,which Kant came to recognize after the MAdN was published, ultimately leads tounderstanding some of the radical revisions of Kant’s epistemology in the opuspostumum, revisions so radical that they constitute a distinctly post-critical phase ofKant’s theoretical philosophy. Kant’s later claims about the Critical philosophy10

have long been suspect among Kant scholars. My aim is to show that some of themost surprising and critical of those claims are correct, and that they require thesorts of remedies Kant contemplates, in particular in the virtually completedmanuscript “Übergang 1–14.” I shall not offer a new account of Kant’s doctrines inthe opus postumum here; but I will defend the (essentially correct) analyses of thismaterial offered by Burkhard Tuschling and Eckart Förster against criticisms maderecently by Michael Friedman.

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Understanding the problems facing the MAdN requires reviewing some mainpoints of its metaphysical method (§III). I then show that Kant’s proof that matterconsists of forces is not only fallacious, but begs the question (§IV). I then re-analyze the circularity in Kant’s definition of density, criticizing both Adickes’formulations and his later dissolution of it (§V). These two fundamental problemsdemonstrate the untenability of Kant’s metaphysical method in the MAdN, and theyrequire (among much else) the radical reassessment of the relation betweenmathematics and metaphysics Kant undertakes in the opus postumum (§§VI–VIII).

II. KANT’S ADMISSION OF THE UNCONSTRUCTABILITY OF MATTER.

According to Gerd Buchdahl, the fundamental forces of matter (repulsion andattraction) cannot be constructed because they fall under the categories of Quality(reality, negation, limitation), all of which are intensive (rather than extensive)quantities. Kant’s justification for introducing forces into the MAdN rests11

ultimately on his claim that in space no activity or alteration, even as a mere motion,can be thought apart from the ascription of causes. Actual causes can only be12

inferred on the basis of empirical data. This follows the doctrine of the first Critique13

that only the form, but not the matter, that is, not the reality, of perceptions can beanticipated. Kant’s success in these constructions lies in the important negative14

point that the existence of an attractive force acting immediately at a distance is anempirical issue that is not precluded by our concepts of matter and force, once thoseconcepts are properly understood. Buchdahl takes this to have been Kant’s main15

aim, and he finds Kant’s greatest contribution to philosophy of science to lie, notin his constructions, but in his tripartite methodological schema of constitutive,regulative, and evidential components of our theoretical knowledge of nature.16

Buchdahl’s work on this tri-partite schema is very insightful, and he is right that thisschema survives the ultimate failure of Kant’s constructive method. However,Buchdahl does not admit how radically he must revise Kant’s own understandingof the division of labor among these three areas in view of the failure of Kant’sconstructive method. Kant insists that pure philosophy is to provide a completeanalysis of the concept of matter as a basis for physics and in particular for theapplication of mathematics to physical phenomena. Buchdahl’s concentration onKant’s systematic architectonic allows him too easily to by-pass Kant’s very strongclaims about how the necessity of natural laws betokens a strong a priori componentin those laws. Indeed, Buchdahl reduces Kant’s quite specific account of theconstitutive component of natural scientific knowledge, which derives from histranscendental idealism in the first Critique and metaphysical constructions in theMAdN, to the mere claim that there is a constitutive component in our naturalscientific knowledge.17

Gordon Brittan contends that Kant is forced to admit that forces areunconstructable by a basic, unresolvable paradox in his philosophy. He gives the18

example that on Newtonian grounds, forces of acceleration cannot be constructedbecause their value shifts with shifts in reference frames. Kant’s 19

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paradoxical result is that the corpuscular hypothesis is mathematically, but notmetaphysically adequate, while his own dynamic hypothesis is metaphysically, butnot mathematically, adequate–-despite Kant’s effort to show that mathematical andmetaphysical adequacy coincide, at least in the case of the dynamic theory ofmatter. Ultimately, Brittan contends, the underlying problem comes from20

distinguishing form and content in a certain way. Forms are determinate, they fitinto a propositional account of knowledge, and they are objective, yet they can neverbe determinate enough to preclude distinguishing from them a content that is real,yet indeterminate and so not objective; determination and reality never quitecoincide. We shall see below, however, that Kant’s admission of the21

unconstructability of matter is quite specific and restricted. If his view faces the kindof global paradox Brittan alleges, it would take much careful argument to justify hischarge. Also, his counter-example, that on Newtonian principles forces areunconstructable, is mis-aimed. His counter-example presupposes that Kant’smetaphysical constructions are to provide the quantitative laws governing forces.(Only on the basis of those laws can any specific values of forces be calculated.)Kant specifically denies this; he seeks to construct forces at a metaphysically generallevel that admits of quantification, but where that quantification must rely onempirical research.22

Robert E. Butts rightly stresses that Kant cannot defer solving the problem ofthe construction of the basic forces of physics until someone more able figures outhow to do it, because if those basic forces are not at present constructed, then theyhave no definite scientific meaning or application, and consequently no concepts ofderivative forces or any other concepts derived from those of the basic forces canhave definite meaning or application. He tries to show that Kant was not bothered23

by the apparent tension between his insistence on the constructability of admissibleconcepts and the non-constructability of fundamental forces because “fundamentalforces” are ultimately regulative postulates of reason that guide research and oursystematic integration of the various physical forces we discover empirically.24

Although Kant suggests once that fundamental forces have such a regulativestatus, this cannot be his real view, or at least not all of it. Kant ascribes a25

fundamental, constitutive status to forces in his theory of matter. The problems withButts’ interpretation have been pointed out by Howard Duncan and KathleenOkruhlik. Duncan stressed that if “fundamental forces” are just regulative ideas,then they must be instrumental and they cannot be explanatory, that is, constitutiveof matter or its possibility. Kathleen Okruhlik further points out that Kant’s views26

contain three importantly distinct kinds of theoretical postulates: purely regulative“necessary fictions,” hypothetical idealizations (including maxima species), andfundamental forces. Butts mistakenly assimilates these three kinds of postulates.27

She argues convincingly that Kant intends a realist interpretation only of thefundamental forces, which is a crucial part of Kant’s effort to provide a realistinterpretation of Newtonian mechanics.28

Howard Duncan points out, against both Buchdahl and Brittan, that the factsthat Kant’s basic forces are a posteriori and fundamental do not suffice to

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explain their unconstructability, since corpuscles are constructable and also are aposteriori and fundamental. He contends that the problem of unconstructability is29

a purely practical, technical problem whose solution awaits the development ofbetter analytical techniques, both geometrical and experimental. Only fully defined30

concepts can be constructed, and definitions are the result, not the beginning, of31

scientific inquiry. Duncan’s approach is obviously the most favorable to Kant, but32

I do not think that he has adequately resolved the strongest doubt about his view,that the constructability of a concept is sine qua non for its scientific acceptability, andfor its role in guiding research. More specifically, Duncan overemphasizes the role33

of geometrical figures at the expense of the more central general problem ofproviding intuitions a priori that correspond to fundamental scientific concepts thatunderwrite the application of mathematics to phenomena, in particular, to applyextensive, quantitative considerations to intensive phenomena.

None of these commentators have grasped the qualifications Kant puts on hisadmission of the unconstructability of matter. Kant’s admission, that when matter(Stoff) is reconceived as fundamental forces, it is no longer possible to construct theconcept of matter and to present it in intuition as possible, is made specifically in34

connection with the issue of density and the corpuscular explanation of density interms of vacant interstices. What he disclaims, just before providing his advice35

about possible lines of construction of the concept of matter, is a sufficient explicationof the concept of matter, and in particular, of density. Kant insists that for his36

metaphysical purposes it suffices to present the filling of space as a dynamicproperty of matter; he claims not to need to specify the laws governing thatproperty, and not to need to explain the further properties of matter such ascohesion, density, fluidity, elasticity, dissolution, decomposition, or specificdifferences among different materials. His optimistic claims to completeness in the37

Preface must concern his essential aim of analyzing matter’s occupation of space indynamic terms.38

However, there are two crucial problems facing Kant’s essential aim to presentthe filling of space as a dynamic property of matter. First, his argument forintroducing forces in the first Proposition of Dynamics is fallacious and begs thequestion. Second, his treatment of density is circular. This second problem showsthat Kant cannot relegate the problem of density to the periphery of his concerns.It incidentally also shows that he cannot dismiss the problem of cohesion as asecondary, empirical concern. Finally, both problems show that Kant’s quasi-mathematical constructive metaphysical procedure is specious. Once Kantrecognized these problems, he saw that their remedy required radically re-casting hisphilosophy of nature, and with that, his Critical philosophy as a whole. Kant’sadmission of the unconstructability of the concept of matter has been discussed withsurprisingly little attention to Kant’s own account of his metaphysical program. Tounderstand Kant’s problems properly, and to understand their theoreticalrepercussions, requires at least a brief review of some central features of Kant’s aimand method in the MAdN.

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III. KANT’S AIM AND METHOD IN THE MADN.

Kant’s MAdN analyses metaphysically the concept of matter presupposed byNewtonian physics, in particular, by its application of mathematics to the behaviorof material bodies. The scope of Kant’s project is set by the intersection of twosenses of “nature.” In the formal sense of the term, “nature” designates the firstinner principle of everything that belongs to the existence of something. In thematerial sense, “nature” designates the totality (Inbegriff) of all things as objects ofour senses. There are two natural realms, the objects of inner and outer sense.39

Kant contends that the objects of inner sense don’t admit of scientific treatment.40

Hence the term that, strictly speaking, covers both possible kinds of science, viz.,“the metaphysical foundations of natural science,” can be used to designate its oneproper part, namely, the metaphysics of corporeal nature.41

Something can affect our outer senses only through motion, Kant claims; hencemotion is the most fundamental characteristic of an object of outer sense. All other42

properties belonging to the nature of matter ultimately derive from motion;accordingly, natural science is pure or applied doctrine of motion. The applied43

doctrine of motion is empirical; Kant’s concern in the MAdN is with the puredoctrine of motion, and indeed only with one of its parts. The pure part of physicsas a natural science contains both mathematics and metaphysics. Physics inevitably44

postulates metaphysical theses about the nature of matter; it needs them in order toanalyze natural phenomena mathematically. Kant’s concern is two-fold. As45

scientific postulates, these metaphysical theses do not receive proper analysis orjustification. Moreover, if they are not properly distinguished from the fundamen-46

tal mathematical principles of physics, this introduces confusion and uncertaintyabout the justification of scientific principles and theory.47

Natural science can be properly scientific only to the extent to which it appliesmathematics to its objects. However, the possibility of applying mathematics to48

objects in natural science presupposes principles for the construction of theconcepts which belong to the possibility of matter in general. Hence a complete49

analysis (Zergliederung) of the concept of matter in general is the basis of naturalscience, and its analysis is the task of pure philosophy. Kant’s MAdN provides50

metaphysical constructions, together with the principles of these constructions, asa distinct discipline which explains and justifies the possibility of mathematicalphysics.51

The MAdN forms a scientific discipline unto itself, and must meet Kant’sgeneral standards of scientific knowledge. A science, on Kant’s view, is a systematicwhole of knowledge organized according to rational principles. Science is pure52

rational knowledge; its fundamental laws are apodeictically certain, and hence mustbe known a priori. These laws, as rational principles, enable us to derive the53

multitude of phenomena that belong to the existence of something from its innerprinciple by reasoning from ground to consequence. 54

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Doctrine based on empirical principles lacks this certainty, systematicity, andnecessity; it is merely historical, and may count as natural history or description ofnature, but it is not, properly speaking, science.55

To justify the application of mathematics to the behavior of bodies withinphysics, the MAdN must be non-empirical, and must be independent of the56

rational principles concerning the use of mathematics in physics. The MAdN must57

be a priori. According to Kant, to know something a priori is to know it on the basisof its mere possibility. However, a priori knowledge of things cannot be based on58

mere concepts, for that only determines the possibility of those concepts, but notof their objects. A priori knowledge of the possibility of things requires that their59

corresponding intuition is given a priori.60

To provide intuitions a priori for concepts is to construct those concepts. In61

this regard, the procedure Kant employs in the MAdN is closely allied to that ofmathematics, since mathematics (on Kant’s view) is rational knowledge through theconstruction of concepts. Consequently, although the pure philosophy of nature62

in general, which examines the constitution of the concept of nature in general (viz.,the first Critique), does not require mathematics, a pure doctrine of nature aboutdeterminate natural things, such as the doctrine of body given in the MAdN, is onlypossible by mathematical means. Kant’s presentation imitates the mathematical63

method for constructing concepts as closely as time allowed him. He thinks that64

the mathematical model is appropriate, and indeed it is required, in view of his aimto provide metaphysical constructions of the concept of matter as the movable inspace, by treating that concept in connection with the forms of intuition and thecategories.

Kant’s metaphysical constructions in the MAdN bring the a priori conceptsanalyzed in the first Critique, the categories, to bear on the intuition of matter inspace, where the empirical concept of “matter” is taken in its most austere, minimalsense as “the movable in space.” The first Critique forms the transcendental part ofthe metaphysics of nature, formulated independently of the nature of either of thekinds of objects of the senses. The MAdN forms the special part of the metaphys-65

ics of nature, which takes the empirical concept of matter and determines the rangeof rational a priori knowledge of this object. The MAdN provides a complete66

analysis of the concept of matter in general as the basis of natural science; this is thetask of pure philosophy. To this end, philosophical analysis needs no particular67

experiences, but only what is found in the isolated empirical concept of matter, inconnection with the pure intuitions in space and time, in accordance with those lawsthat depend on the concept of nature in general (that is, the principles of the firstCritique). This analysis is an actual metaphysic of corporeal nature. The68 69

completeness of this analysis is guaranteed by the Table of Categories of the firstCritique.70

The Table of Categories sets out the general laws of thought. Whether it be71

a priori, based on mathematical construction, or learned by experience, whatever maybe thought about matter must fall under the four functions of thought, viz., quantity,quality, relation, and modality. To each of the four 72

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functions of thought, or headings in the Table of Categories, there corresponds achapter of the MAdN. Each chapter adds a new characteristic to the basic conceptof matter as “the movable in space.” The first chapter, titled “Phoronomy,” treats73

motion as a pure quantity capable of composition (pure kinematics). The secondchapter, “Dynamics,” adds a qualitative characteristic to the concept of matter,namely, that it has an original moving force. The third chapter, “Mechanics,”explicates matter as the movable insofar as it has moving force; it treats the74

relations among moving material bodies. Finally in “Phenomenology,” matter isexplicated as the movable insofar as it can be an object of experience. This75

involves treating relative motions in connection with our power of representationas an appearance of outer sense, and determines their modality; ultimately this76

provides the metaphysical principles requisite for distinguishing true from apparentmotions. Each of these explications is more substantive than its predecessors, and77

Kant’s justification and explanation of each presupposes the preceding explicationsand the soundness of their justifications.

Through these methods, Kant proposes to prove a priori three fundamental lawsof (broadly Newtonian) mechanics. He does this by applying the three Principlesdefended in Analogies of Experience in the first Critique to the empirical concept ofmatter as the movable in space, as that concept is sequentially explicated in each ofthe chapters of the MAdN. The three Principles are that substance is permanentthrough all change, that every change has a cause, and that causal interaction isreciprocal. Kant’s three laws of “Mechanics” (MAdN ch. 3) are that the total78

quantity of matter remains constant through all changes in corporeal nature, thatevery change in matter has an external cause, and that action and reaction are equalin all communication of motion. Kant regards his a priori proofs as an advance over79

the empirical proofs offered by Newton and other physicists.80

IV. KANT’S PHORONOMIC BASIS FOR DYNAMICS.

In “Dynamics,” Kant explicates matter as the movable insofar as it fills a space,where matter fills a space (as distinct from merely occupying it) insofar as it resistsany other body that tends to enter that space. At first glance it may seem that81

Kant’s first explication of matter in “Dynamics,” as something that fills a space byresisting the entry by other bodies into the space it occupies, simply asserts adynamic theory of matter, since resistance would seem to be the effect of some sortof causal force. This appearance is misleading. The idea that matter resistspenetration of the space it occupies is held in common by corpuscular theories andKant’s dynamic theory of matter. The crucial point concerns how each theoryexplains this resistance. According to corpuscularism, matter is particulate, and thebasic particles of matter are essentially impenetrable. Impenetrability is a fundamen-tal property of matter, and not the effect of some more basic kind of force. The onlyactive forces there are, according to corpuscular doctrine, are forces imparted fromwithout by impact. Kant initiates his argument against corpuscularism with the firstProposition

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(Lehrsatz) of “Dynamics,” that matter fills a space not simply by existing, but by aparticular moving force. Kant’s proof of this proposition rests explicitly on the82

Proposition proven in “Phoronomy.” Unfortunately, his proof is fallacious and it83

misrepresents the Phoronomic Proposition. Seeing why this is so, and what theimplications of this are, requires examining some of the main aims and doctrines ofKant’s first chapter, “Phoronomy.”

Kant’s aim in “Phoronomy” is to set out the purely quantitative characteristicsof motions and their combinations in order, ultimately, to provide a conspicuousphysical account of the combination of motions effected by actual causes. More84

specifically, Kant is concerned to provide a clear account of the purely quantitativeaspects of motions, the extensive magnitudes of space traversed (including direction)within an elapsed time, in order to clarify the intensive aspects of motions,beginning with the rates of changes of place (velocity). Kant rightly remarks that85

it is not self-evident that velocities (quite apart from accelerations) are inherentlyadditive in the way that the extensive quantities of distance or volume are.86

Consequently, “Phoronomy” is a pure kinematics that abstracts from all causalconsiderations and treats solely the quantitative aspects of motion, direction andvelocity, and the quantitative combination of motions.87

Although “Phoronomy” abstracts from causes, Kant plainly intends to treatmotions that can have a physical basis. Because Phoronomy cannot treat motionsthat have causes, such as curvilinear motions, it is restricted to rectilinear motions(which can be inertial). Kant thus needs to treat combinations of rectilinear88

motions in the same direction, in opposite directions, and in divergent directions(where the directions of the motions form an angle). Since these are supposed to89

be cases of combined (rather than successive) motions, they must be motions of thesame point at the same time. Kant repeatedly insists that combinations of motions90

in the same space can only be understood in causal terms, and conversely, thatpurely quantitative (non-causal) combinations of motions require distinct spaces.91

These distinct spaces are relative spaces which, like modern reference frames, canbe understood to move with respect to each other within a larger relative space (orframe of reference). Absolute motion is a fiction, and absolute space is merely anidea of reason in accordance with which we can construct ever larger, more inclusiverelative spaces. A relative space may be treated as “absolute” for purposes of92

analyzing motions within it, whether those motions be of bodies or of other relativespaces. “Motion” is thus relative to what is regarded as stable, which may be either93

a body or a relative space (or, reference frame).94

One point that distinguishes Phoronomy from geometry is that Phoronomyincludes considerations of time, the time that elapses during a motion. Motions95

occurring at different times are distinct motions. Since Phoronomy treats thecombination of motions, the combined motions must be understood as occurringsimultaneously. This cannot be achieved by chronometric means, where we woulddetermine the equal duration of motions occurring at different times and computetheir combination, simply because chronometric techniques

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of any kind presuppose what Kant’s phoronomic constructions are supposed toprove, namely, that mathematical measures can be applied to experienced motions.96

Consequently, Kant’s phoronomic constructions of combinations of motions mustallow the two combined motions to occur simultaneously. (The problems involvedin combining more than two motions reduce to those of combining two motions. )97

The two combined motions are motions of the same point, and the two componentmotions are to be contained in the resultant motion; they are not to produce a thirdmotion. In this way Kant seeks to make intuitively evident a priori the geometrical98

congruence between the two combined motions and a third motion, which, under99

physical conditions, would be their result. Consequently, Kant’s phoronomicconstructions must use simultaneous motions of or within distinct relative spaces.100

Kant summarizes these doctrines in the sole Proposition defended in “Phoronomy:”

The composition of two motions of one and the same point can only be thoughtof by one of them being represented in absolute space, but instead of the secondmotion being so represented, a motion of the relative space in the oppositedirection and with the same velocity is represented as being identical with the firstmotion. (MAdN 4:490.7–13)

It is sufficiently evident that the composition of two motions can be represented byrecourse to distinct relative spaces or frames of reference; the important point forpresent purposes is why Kant thinks it can only be represented in this manner, forthese reasons underscore the necessity of distinguishing relative spaces inphoronomic constructions.

Kant’s proof of the Phoronomic Proposition is divided into three cases; twomotions in the same direction, in opposite directions, and in diverging directions.In the first case of combining two motions in the same direction, a line segment ina single space that represents the total distance traversed by the combined motionsmust be understood as occurring in the same period of time as each of thecomponent motions; otherwise that line segment would not represent the combinedvelocities of those two motions. Consequently, no parts of that line segment canrepresent either of the component motions, because the distances represented byany sub-segments of that line segment cannot themselves be understood as beingtraversed in the very same period of time as either of the component motions. (Theperiod of time in which any sub-segment is traversed must be less than the totalelapsed time, yet each of the component motions lasts the whole elapsed time. )101

Consequently, one line segment in a single space cannot represent the combinedvelocities of the two motions.102

The second case combines two motions of the same point in oppositedirections. Kant simply asserts that the thought of combining two such opposedmotions of the same point at the same time in the same space is simplyimpossible. The impossibility apparently lies in the fact that such an intuitive103

construction would at best present the difference between the two motions, andwould fail to represent the two component motions themselves, whereas represent-ing those component motions was the very point of the construction. As in

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the first case, recourse to distinct relative spaces is the only way to represent the twocomponent motions and make intuitively evident their congruence with some thirdmotion.

The third case combines two motions of the same point in diverging directions.Once again, attempting to construct such a combination in a single space fails torepresent either of the component motions. At best, such a construction wouldpresent the vector sum of the two component motions, as the product of the twocomponent motions’ mutual alteration. Kant insists that the point of his phoronom-ic constructions is that the two component motions should be contained in a thirdmotion, not that either of them should be altered nor that they should produce athird, distinct motion. Once again, the only way to represent the two component104

motions as being contained in a third motion is to construct the two motions indistinct relative spaces.

My point in reviewing these doctrines from “Phoronomy” is to show as clearlyas possible the problems Kant creates when he cites the Phoronomic Propositionin his proof of the first Proposition of “Dynamics,” that matter fills space in virtueof its moving force. Kant’s Proposition 1 of Dynamics and its proof are as follows:

Proposition 1. Matter fills a space, not by its mere existence, but by a specialmoving force. (MAdN 4:497.14–16.)

Proof. Penetration into a space . . . is a motion. The resistance to motion is thereason why motion diminishes or even changes into rest. Now, nothing can becombined with any motion as lessening or destroying it but another motion of thesame movable thing in the opposite direction (phoronomic proposition).Consequently, the resistance offered by a matter in the space that fills it to allintrusion by another matter is a cause of the motion of this other matter in theopposite direction. But the cause of a motion is called moving force. Consequently,matter fills its space by moving force and not by its mere existence. (MAdN4:497.17–28.)105

In response to Tuschling’s critique of Kant’s MAdN, James McCall cites most ofthis passage (beginning with the third sentence, “nothing . . .”) and states:

[Kant] is not arguing here that force is nothing but an opposition of perceptiblemotions but, rather, that force is effective in resisting a motion only through themediation of a motion in the opposite direction. I find here no derivation of forcefrom motion – only the recognition that motion can be opposed only by motion.106

However, McCall does not examine Kant’s Phoronomic Proposition or what Kantcould possible mean by citing it in this proof. Examining Kant’s use of thePhoronomic Proposition in his proof of the first Proposition of Dynamics re-confirms Tuschling’s charges that Kant here attempts to derive forces from motions,and that this derivation fails. Kant’s proof both begs the question and mis-uses hisown Phoronomic Proposition.

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Kant’s “Phoronomy” is a purely quantitative analysis of the direction andvelocity of motions, and specifically excludes any analysis of their causes. Themotions at issue in Kant’s proof that matter has a moving force are entries ofmaterial bodies into spaces occupied by other material bodies, and the doctrine ofmotion that provides the principles of Kant’s proof is Phoronomy. In his proofKant prominently appeals to the Phoronomic Proposition; remove that appeal andhis argument is incomplete. Consequently, his inference from changes of motions,to causes of changes of motion, to moving forces as causes of changes of motions,is, as Tuschling claims, an attempt to derive forces from motions, insofar as Kantargues that only by postulating fundamental moving forces can matter be conceivedto fill space.

There are two main problems with Kant’s appeal to the Phoronomic Proposi-tion in his proof that matter fills space by its moving force. Kant cites thePhoronomic Proposition in the following way: “. . . nothing can be combined withany motion as lessening or destroying it but another motion of the same movablething in the opposite direction (phoronomic proposition).” The most obvious107

problem is that Kant here speaks of one motion “lessening or destroying” anothermotion. In this context, “destroying” (aufheben) and “lessening” (vermindern) either arecausal terms or they are not. If they are not causal terms, they do not serve tointroduce forces into Kant’s argument. Hence forces must be introduced by othersof Kant’s premises. I shall show below that the other premises cannot do thisvalidly. If they are not causal terms, they cannot serve as the inferential link Kant’sargument needs to show that matter’s resistance to penetration is a cause of itsrepelling other bodies. If they are causal terms, they cannot be justified by appeal tothe Phoronomic Proposition. Causal terms were explicitly and repeatedly excluded108

from Phoronomy in general, and they certainly do not appear in Kant’s statementof the Phoronomic Proposition. Consequently, Kant cannot justify their109

introduction into his proof of the first Proposition of Dynamics by citing thePhoronomic Proposition.

Whether those terms are causal or not, there is another, equally serious problemwith Kant’s citation of the Phoronomic Proposition in this proof. In order for onemotion to decrease or destroy another motion, those two motions must not only bemotions of the same body, they must occur in the same space. However, as we haveseen, the very point of Kant’s Phoronomic Proposition and its proof was to showthat the phoronomic construction of combinations of motions required distinctspaces for each motion. Consequently, Kant cannot justify the central premise of hisproof, that “nothing can be combined with any motion as lessening or destroyingit but another motion of the same movable thing in the opposite direction,” byappeal to the Phoronomic Proposition.110

It may seem that Kant’s proof could be supported, not by the PhoronomicProposition itself, but by part of its proof, specifically the negative part that aimedto show that combining motions in the way required by phoronomic constructionscould not be achieved in a single space. Kant’s sub-proofs show that combiningmotions in a single space results in a motion that is their

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product, but which does not contain them as components. Could these sub-proofsbe turned into a proof that the motion that results from combining motions in asingle space is a causal product of causally active material bodies? No. Kant doesinsist, in the third sub-proof, that the “alteration” or the “production” of a thirdmotion is excluded from Phoronomy, and yet is required in order to construct thecombination of diverging motions in the same space. However, the alteration and111

production at issue in that sub-proof are strictly quantitative, mathematical notions.Each of Kant’s sub-proofs treats motion in strictly quantitative terms, and none ofthem analyzes the causal etiology of motion. Consequently, those sub-proofs cannotthemselves be used to justify the introduction of causal terms into Kant’s proof ofthe first Proposition of Dynamics. On the contrary, those sub-proofs underscore theoriginal point that appealing to Phoronomic considerations in a proof that matteris invested with moving forces amounts to an attempt to introduce forces on thebasis of motions, and it underscores Tuschling’s original criticism of Kant’s proof,namely that motions alone do not suffice to justify the introduction of forces. Kant’sproof of the first Proposition of Dynamics is fallacious. Kant’s inference, that“Consequently, the resistance offered by a matter in the space that fills it to allintrusion by another matter is a cause of the motion of this other matter in theopposite direction,” does not and cannot follow from the Phoronomic Proposi-112

tion.It may be suggested that Kant’s proof could be supported instead by his

repeated claim that motions can only be combined within a single space by recourseto causes. Though this may seem to be the needed principle, Kant merely asserts113

that principle without argument, and in fact it is not the requisite principle after all.Instead, close examination of this claim reveals another fallacy in Kant’s argument.Although these causes must be some sort of “moving causes,” in two of the three114

passages in which Kant makes this claim he rightly indicates that the causes requiredto combine motions in a single space are “external” causes. “External causes” are115

not identical to the “moving force” Kant seeks to show is an essential internalproperty of matter in the first Proposition of Dynamics and its proof. Kant’s proofends with the inference that “the cause of a motion is called moving force.Consequently, matter fills its space by moving force and not by its mereexistence.” This is a non sequitur; “the cause of motion” to which Kant appeals is116

the cause of something’s moving; it is not the cause of something’s filling space, noteven if the resistance whereby a body fills a space is part of what enables that bodyto impart motion to another body (as Kant states both in the immediately precedingpremise and in the second sentence). The issue is what accounts for that resistance117

to penetration, and Kant’s proof does nothing to advance his case againstcorpuscularism, which accounts for that resistance by ascribing impenetrability tomatter. Kant is quite right that the law of contradiction doesn’t repel any materialbodies. However, according to corpuscular doctrine, what would violate the law118

of contradiction is a piece of matter that lacks impenetrability; impenetrability itselfis a physical property of matter, and this prop-

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erty of a material body is what resists the intrusion by other bodies into the spaceit occupies. Kant’s argument does nothing to show that what repels the penetrationof a body into the space occupied by another body is a moving (repulsive) forcerather than impenetrability. His argument does not show that material bodies inmotion, whatever may be the external causes of their motion, affect each other’smotion on contact in virtue of internal forces that are essential to matter. Kant’s119

conclusion, that a moving force is what enables a matter to fill space, simply begsthe question against corpuscularism.

Kant’s proof of the first Proposition of Dynamics is unsound. Indeed, theproblems with his proof are so great that it’s surprising Kant didn’t notice themimmediately. As Tuschling notes, the problems with Kant’s proof did not escape thenotice of one of the first reviewers of the MAdN. On December 2, 1786, ananonymous review of Kant’s MAdN appeared in the Göttingische Anzeigen von gelehrtenSachen No. 191. The reviewer said the following about Kant’s chapter on “Dynam-ics:”

2 Chapter. Metaphysical Foundations of Dynamics. Here matter is the movablend

that fills space; to fill space is to resist everything movable that by its motion tendsto enter a specific space. Matter fills space, not by its mere existence, but by amoving force – since its resistance to that which tends to enter changes its motion,and nothing can reduce or destroy motion except motion in the opposite direction.To support this the Phoronomic Proposition is cited. (Phoronomy contains thesole Proposition, previously cited, concerning combined motion. The reviewerconfesses that he presently doesn’t find the same expressly, and, even if he mayhave also overlooked something, doesn’t understand how this could follow fromthe Proposition cited. A body that moves admittedly remains at one and the sameplace in absolute space if the plane on which it lies is moved in precisely theopposite direction with the same velocity, but must every persisting at a place bethought in this way? Must a moving force be ascribed to a wall because one cannotproceed past the wall? It is not at all evident how one can base moving force onmotion, whatever its source.)120

As we have seen, Kant’s proof of the first Proposition of Dynamics does notcontain an adequate answer to this reviewer’s questions; it does not prove thatmatter fills space in virtue of an original moving force. Tuschling notes that Kantquoted this passage almost verbatim on one of the loose leafs found with the IV.Convolut of the opus postumum (Loses Blatt 25). Adickes dates the leaf only as prior121

to 1796. Kant read literary reviews avidly and anxiously awaited a response to theMAdN, especially from Göttingen, home of the physicist he esteemed so highly,Lichtenberg. His transcription is likely have been made shortly after the review122

would have appeared, no later than 1787. He doesn’t comment on the problem onthat leaf, but he must have meditated on it long and seriously. As Adickes noted,Kant tried throughout his career to demonstrate some version of the firstProposition of Dynamics, never with

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success. One of the questions Kant had to answer when considering the123

reviewer’s objection is where the ultimate source of his difficulty in demonstratingthat matter consists of moving force lies. That source becomes more evident afterexamining a further problem with his theory of matter Kant noticed a few yearslater. Even when the reviewer pointed out that Kant’s proof was problematic, Kantdid not immediately see why. In the midst of his transcription from the review, Kantinserted a parenthetical note defending his appeal to the Phoronomic Proposition:“(N.B.: The phoronomic proposition was cited by me to support the claim that nothingcan abolish motion save motion in the opposite direction.)” Kant still insisted here124

on speaking of motion being “abolished,” but for reasons just given, that is the kindof causal idiom which he specifically and of necessity excluded from Phoronomy,and it requires motions in the same space, which was also necessarily excluded fromPhornomy.

V. THE CIRCULARITY IN KANT’S DEFINITION OF MATTER’S QUANTITY.

Kant’s dynamic theory of matter in the MAdN faces a fundamental problem ofcircularity, and this circularity reflects directly back onto the tenability of hismetaphysical approach to constructing the basic concepts necessary for thepossibility of matter. While expositors sympathetic to Kant’s MAdN have ignoredthis problem, critics who have emphasized this problem have relied on Adickes’sinitial formulation of it, and haven’t considered Adickes’s later retraction of thedifficulty. Although it is on the right track, I contend that Adickes’s initial125

formulation is not adequate, and that his later dissolution fails. I develop animproved statement of the problem of circularity, and show how fundamental thisproblem is within Kant’s theory of matter. In §VI I show how it reflects adverselyonto his constructive metaphysical method.

The aim of Kant’s dynamic theory of matter is to explain the fundamentalproperties of matter in terms of fundamental moving forces. To do so, he mustdescribe those forces in such a way that he can preserve the main physicaldefinitions and laws of matter. Matter fills space through its moving forces, more126

specifically, through the mutual limitation of its attractive and repulsive forces.127

Matter fills a space by repelling other things from the space it occupies. The action128

of repulsion alone would dissipate matter throughout space. The action of129

attraction alone would compress matter into a mathematical point which may belocated in space, but would not occupy space and so would not exist; space wouldbe left empty. Hence a material substance exists and fills a space through the130

interplay of its attractive and repulsive forces; both are essential to matter.131

Problems arise when Kant tries to specify the volume and density of matter. Thespace a matter fills is determined by the balance between the attractive and repulsiveforces. Density is a function of the intensity with which the two opposed basic132

forces fill a region of space. The attractive force, which Kant ultimately identifies133

with Newtonian gravitation, is supposed to be the same in all materials. Repulsiveforce, which acts only at the surface of a matter, and

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hence only on contact, is supposed to differ in different materials. In this way, Kantseeks to account for different densities of different materials as an original propertyof those materials, without recourse to the corpuscular hypothesis of vacantinterstices between otherwise equally dense fundamental particles.134

Kant himself came to think that his analysis was circular. Adickes cited the tworelevant passages. The first passage comes from Kant’s remarks on a letter hereceived from J. S. Beck (8. Sept. 1792):

[PASSAGE I] The greatest difficulty is to explain how a specific volume of materialis possible by the inherent attraction of its parts in the ratio of the inverse squareof the distance, [in conjunction] with a repulsion, which can only affect those partswhich are in immediate contact (not those at a distance), in the ratio of the cubeof the distance (and hence of its volume). Thus the power of attraction dependson density, but density depends again on the power of attraction. Also, densityvaries in accord with the inverse ratio of repulsion, that is, of the volume. (XI 1st

ed. 348; 2 ed. 361.30–362.2; my tr.)nd 135

The second passage comes from Kant’s reply to Beck of 16. October 1792. Kantpraises Beck for recognizing the importance of the physical question of explainingdifferences of density without recourse to vacant interstices. He then states:

[PASSAGE II] I would of course set up the solution of this problem as follows, that

attraction (universal, Newtonian) originally is equal in all materials while only the

repulsion of different materials differs, and thus constitutes the specific differences

of density. But this leads in a certain way to a circle I can’t get out of and which I

myself must try to understand still better. (XI 1 ed. 362; 2 ed. 376.35–377.4; myst nd

tr.)136

Adickes offers two different accounts of Kant’s problem, along with two differentassessments of its severity. The differences between his accounts are instructive;examining them will enable us better to grasp the real dimensions of the problemKant faces.

In his editorial apparatus to Kant’s Reflexionen zur Physik und Chemie, Adickesexplains the problem as follows:

[ADICKES 1911] This “circle” is also found in the “Metaphysical Elements ofNatural Science” and consists in this: gravitational attraction is proportional tomass, and thus (with equal volumes) is also proportional to density. But this densityis supposed in turn to be dependent upon that same attractive force, taken inconnection with the original repulsive force. Repulsive force differs in differentmaterials; but attractive force on the contrary is not supposed to differ in differentmaterials. It is always the same degree, and is proportional only to the quantity ofthe material. However, only through the “effect and counter-effect of both” ofthese

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“basic forces is a determinate degree of the filling of space” and so also thequantity of material “possible” (MAdN 4:521.7–8). Thus how could the basic forceof attraction be proportional to this quantity, which is still undetermined, andindeed which presupposes that force? It is in fact a “circle” in which Kant moves. . . (XIV 337.35–338.4; my tr.; quotation marks indicate Adickes’s quotations fromKant.)

In 1911 Adickes thought this problem was genuine and required radical alterationsof Kant’s theory, in particular, the recognition of two distinct kinds of attractiveforce. I shall argue below that Adickes was right about this, and further that the137

implications for Kant’s method of recognizing two distinct kinds of attractive forceare very serious. But first we should examine the weakness of Adickes’s laterpresentation and resolution of the circle problem.

Adickes subsequently described the circle problem in the following terms:

[ADICKES 1924A] If one says: it is one and the same attractive force, which on theone hand, together with the repulsive force, constitutes matter and thus also itsquantity (mass), and which on the other hand depends of course again in its degree,as gravitational attraction, from precisely this mass . . ., then the circle is altogetherundeniable: the presupposition of mass should equally be its consequence. (Kantals Naturforscher §85 [vol. I, 215]; my tr.)

In 1924 he thought the solution to the problem required nothing more thanredescription:

[ADICKES 1924B] But one can also describe the circumstance differently, bybeginning with the repulsive force and saying: the repulsive force that is present ina region of space determines through its degree the amount of attractive force thatis possible in that region, and indeed in such a way that this amount always standsin inverse proportion to the repulsive force. Once again mass is directly dependentupon the degree of attractive force; mass and attractive force (which as one and thesame [force], on the one hand helps to constitute matter, and on the other handproduces gravitational effects), are therefore proportional to each other. With thisway of regarding and presenting [the issue] one can no longer speak of a circle.(Ibid.; my tr.)

Adickes’s 1924 formulation of Kant’s problem (ADICKES 1924A) captures the mainpoint of his 1911 formulation (ADICKES 1911), according to which gravity cannotboth be presupposed by a quantity of matter (as one of the two fundamental forcesthat constitute that quantity), and also depend on that quantity for determining itsstrength (in the Newtonian manner according to which gravitational force is directlyproportional to mass). I shall argue that this problem is genuine, that it is notrelieved by Adickes’s redescription (ADICKES 1924B), and that it is only one amonga knot of closely related problems infecting Kant’s dynamic theory of matter.

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The first thing to notice about both of Adickes’s formulations of Kant’sproblem (ADICKES 1911, ADICKES 1924A) is that they diverge from Kant’sstatements in an important regard. Although Adickes’s 1911 formulation begins bymentioning volume and density, these terms are dropped by the end of hisstatement; ultimately nothing about density enters into either of his statements ofthe problem, even though Kant formulates his problem of circularity expressly interms of density. Another shortcoming of Adickes’s 1911 formulation (ADICKES

1911) is that he does not consider the possibility that what might seem to be acircularity is in fact an interdependence. Indeed, this possibility is just what his 1924solution (ADICKES 1924B) exploits. Most importantly, Adickes’s solution introduces,without explanation, a puzzle of its own, namely the claim that attraction (notdensity) is inversely proportional to repulsion. I shall argue that Adickes’s latersolution fails. The reasons for this failure afford an improved formulation of Kant’sproblem.138

In 1924 Adickes suggested that the problem is merely verbal, because one canspecify the relation between the two fundamental forces and mass by beginning withthe repulsive force. The strength of the repulsive force within any region of spacedetermines inversely the strength of the attractive force possible within that sameregion. In this way, attractive force and mass are directly proportional, and there isno circularity, even though the attractive force has two roles, one as constituting thequantity of matter, the other as the source of gravitational attraction. However, thissimple solution omits consideration of density, it departs from Kant’s account ofattractive force in a significant regard, it inverts the relation between attraction andmass by making mass dependent upon attractive force (i.e., gravity), and it introducesa spurious problem about the quantity of matter.

Kant insists that the attractive force is a constant in all materials. Adickes departsfrom this (in ADICKES 1924B); he must explain and justify his claim that the strengthof the attractive force within a region of space could vary inversely with the strengthof the repulsive force. Perhaps the net effect of these two forces would vary withdifferences in the repulsive force, but Kant cannot allow that the strength of theattractive force itself varies inversely with the strength of the repulsive force in anyregion of space. In effect, Adickes’s 1924 solution to the problem implicitlyintroduces, without explanation, a second kind of attractive force, which is what his1911 solution did explicitly.

Most importantly, Kant formulated his problem of circularity in terms of volumeand density; he did not formulate it in terms of mass or the quantity of matter.Adickes substitutes these latter terms for the former. This introduces anotherproblem of circularity, but it is merely a corollary to the problem Kant formulates.The passage Adickes cites concerning “the quantity of matter” is the following:

Therefore, the original attraction of matter would act in inverse proportion to thesquare of the distance at all distances and the original repulsion in inverseproportion to the cube of the infinitely small distances. By such an action andreaction of both fundamental forces, matter would be possible by a determinatedegree of the filling of its space. (MAdN 4:521.4–7)

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Kant speaks in this passage of the determinate degree to which a matter fills itsspace, but he does not speak either of the quantity of matter or of mass. This is notaccidental. Although it seems intuitively obvious that Kant ultimately would haveto define (or at least explain) mass and the quantity of matter in terms of theintensity with which a matter fills space, he in fact does not make this connectionin the MAdN. Kant does not define either the quantity of matter or mass within hischapter on “Dynamics;” he defines them only in the next chapter, “Mechanics.” Inthe second Explication of Mechanics he defines the quantity of matter in terms ofthe amount of the moveable in a determinate space, which constitutes mass, and inthe first Proposition of Mechanics he insists that the quantity of matter can only beestimated by comparing the motions of different bodies. He contends that no139

matter would have moving mechanical forces if it did not have the “original”moving forces explicated in “Dynamics,” but he does not explicitly or directly140

relate either mass or quantity of matter to the intensity of the “original” forces ofattraction and repulsion with which a matter fills its space. Adickes’s initialformulation (ADICKES 1911) thus inserts a conceptual, definatory relation intoKant’s account that Kant himself did not formulate.141

Moreover, in “Dynamics” Kant speaks quite generally of “attractive force,” butdoes not equate this force with gravity. Adickes insists on treating the “attractiveforce” involved in Kant’s circularity as a gravitational force. This is, I believe,correct, but it must be explained. While Kant himself equates attraction and gravityin his letter to Beck (PASSAGE II), his original formulation (PASSAGE I) does not doso. In his original formulation Kant does ascribe to attractive force the familiarinverse square rate of diminution. While this may suggest Newtonian gravitation, itis not decisive; like the illuminating power of light, other forces can have that samerate of diminution. However, Kant contends that there can be only two142

fundamental forces, one attractive and one repulsive. Consequently, he must143

identify gravitational attraction with his original attractive force. Indeed, Kantidentifies the two of them already within his “Dynamics.” Kant’s problem of144

circularity arises strictly within Kant’s dynamic theory of matter, and does notinvolve the relation between his “Dynamics” and his “Mechanics.” In particular,Kant’s problem of circularity does not involve his concepts of the quantity of matterand of mass, which are treated only in “Mechanics.”

By ignoring the terms in which Kant originally formulated his problem (volumeand density), and by inserting terms foreign to Kant’s formulation (quantity ofmatter and mass), Adickes generated a different problem than what Kant himselfformulates. While Kant’s view does face a problem like the one Adickes formulates,that is merely a corollary to the fundamental problem infecting Kant’s dynamictheory. Kant’s problem concerns the relations among the two fundamental forces,volume, and density.

Kant holds that the volume of a basic matter is a function of the balancebetween its fundamental attractive and repulsive forces. (Notice that Kant speaks145

of the “parts” of a matter in the MAdN and in his notes on Beck’s letter. I speak146

of “basic matters” to avoid exacerbating the atomistic ten-

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dency of Kant’s view.) The only thing that can limit a fundamental force is anopposing fundamental force. The volume or the space a basic matter fills must be147

a sphere whose radius is determined by the distance from their center point at whichthe two fundamental forces balance each other. Now the attractive force issupposed to be constant in all materials, while the repulsive force is supposed todiffer, and such differences are supposed to account for differences in density. Thisstrategy cannot work. The balance between the two forces is struck at whateverpoint their respective strengths are equal (though opposed). One problem is that adifferent degree of repulsive force will change the spatial determination (the radiusof a spherical surface) at which this balance occurs, but not the scaler intensities ofthe forces involved. Because the attractive force is constant, the repulsive force thatbalances it cannot change in scaler degree, however much it may change in intensity.Instead, the volume occupied by those balanced forces will vary inversely with thestrength of the repulsive force. Kant’s theory of the volume and density of matteras a function of the balance of the two fundamental forces entails that basic matterswith different degrees of repulsive force must differ in volume! They will thus alsodiffer in density because a stronger repulsive force will balance the same degree ofattractive force within a smaller volume, but the total (scaler) quantity of these forcesmust be the same in all basic matters. Thus basic matters must all fill their respectivespaces to the same (scaler) degree of intensity. This is absolutely not the result Kantsought or claimed; he claimed to have a theory according to which the same sizedbasic matters could differ in density. Kant’s dynamic theory of matter thus leads148

quickly in the direction of either corpuscular atomism or physical monadology, bothof which he sought to avoid. Notice, too, that Kant is quite right (in PASSAGE I)149

that the problem of density arises in connection with the question of how adeterminate volume of matter is constituted by the opposition of the two basicpowers of attraction and repulsion.

Once Kant’s basic matters are found to fill different spherical volumes of spaceto the same degree, Kant will be forced to account for differences in densitybetween the equal volumes of materials of different densities in terms of thedifferent number of basic matters contained in each respective volume of material.In fact, in “Mechanics” Kant does define the quantity of material in terms of the“amount” of the moveable found in a specific space, but he does not seem to150

recognize that he must treat this “amount” in terms of a number of discretespherical basic matters. Once Kant is forced to account for differences of densityby recourse to different numbers of different sizes of basic matters, his theorygenerates the same license to speculate for which he so sharply criticizedcorpuscularism. Because matter is constituted by the balance of two opposed151

fundamental forces taken as radiating out from a common point, these basic mattersmust be spherical. Spheres do not conjoin into larger volumes without either largedistortions or vacant interstices. On the latter option, Kant’s view would entail thatdenser materials have more inter-

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stices of smaller volume than do less dense materials of equal total volume.Interstices may not be explanatory on this account, but there they are, and they arejust as vacant as the corpuscular interstices Kant sought to banish for not beingobjects of possible experience. On the former option, according to which152

originally spherical basic matters form larger solid materials through distortion oftheir spherical forms, speculation must abound about the processes through whichor the functions according to which these distortions and combinations occur. Forbridling speculation, Kant’s dynamic theory of matter looks little or no better thancorpuscularism. I do not see any way for Kant to avoid the result that his basicmatters are spheres which either form interstices when compounded into largervolumes of matter, or which must undergo radical changes of shape whencompounded.153

Kant can only avoid the other result, that different materials with differentdensities will consist of different sizes of basic matters, by distinguishing twodifferent kinds of attractive force, one that is responsible for the basic constitutionof matter, and another that is responsible for gravitational attraction. Moreover, theattractive force responsible for the basic constitution of matter would have to varydirectly with the absolute value of the repulsive force, and both would vary directlywith density (for any given volume). Gravitational attraction would then have to bea second kind of basic power of attraction, one that depends directly upon densityand volume. I shall argue shortly that admitting two fundamental kinds of attractiveforce is tantamount to admitting the untenability of Kant’s constructive metaphysi-cal methods (§VI). First we need to be quite clear about why Kant is forced to admittwo different kinds of attractive powers. Clarifying this point requires answering theoriginal question, What exactly was Kant’s problem with circularity? How doesdensity figure into that problem?

Notice that PASSAGE I speaks of “the greatest difficulty,” and formulates acircularity: attraction depends on density, which in turn depends on attraction.Kant’s reference to the “greatest” difficulty suggests that Kant is troubled by morethan one problem. Consider again the elements in Kant’s first formulation. Kant’stheory of matter requires that the two basic forces differ in certain regards if they areto make matter possible. If they are not simply to neutralize one another altogether,they must act differently and, Kant thinks, they must diminish with distance atdifferent rates. Kant claims that the power of attraction is a penetrating force,154

effected by all the parts of a material body and effective immediately (withoutcontact) through all of space. He also ascribes to it a rate of decrease that is the155

inverse of the square of the distance it extends. He claims that the power of156

repulsion is a superficial force, effective only at the surface of contact betweenbodies, and effected by only those parts of the bodies that are in contact. He also157

ascribes to it an inverse cube rate of diminution. Hence the power of repulsion158

varies directly with volume. Kant says (in PASSAGE I) that his “greatest difficulty”159

lies in explaining how a specific volume of matter is possible on the basis of thebalance between

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these two powers. This difficulty cannot lie in specifying the laws according to160

which these two powers function; those laws belong to mathematical physics, notto metaphysics. Kant’s problem must lie in his fundamental metaphysical concepts161

and constructions. Kant’s problematic is set, of course, by the Newtonian physicalprinciples whose metaphysical basis he sought to provide. According to Newtonianprinciples, the power of attraction is proportional to mass, and within a givenvolume mass is proportional to density. Hence, within a specific volume, the powerof attraction must be a function of density. This is contrary to Kant’s official view,according to which density is supposed to be a function of the balance of the twofundamental powers.162

It may seem that Kant’s problem rests on a simple oversight. On the generalprinciples of Kant’s dynamic theory of matter, density should be a function of thedegree to which a given region of space is filled by mutually counterbalancingattractive and repulsive forces. In this way, density should be directly proportionalto the combined absolute value of the intensities of these two forces. One historicalpoint needs to be set aside in order to appreciate the metaphysical difficulty facingKant’s dynamic theory. The definition and symbolism for absolute value (the valueof a magnitude irrespective of its sign) had not been developed in Kant’s day.163

However, introducing the concept of absolute value won’t solve Kant’s problem atthis point; on the contrary, introducing this concept helps to show clearly the natureof the metaphysical problem Kant faces.

On Kant’s theory, density should indeed be directly proportional to thecombined absolute value of the intensities of the two fundamental forces thatcounterbalance each other in any basic matter. However, to preserve the Newtonianprinciple that gravitational attraction is proportional to mass, Kant must distinguishbetween gravitational attraction and the original power of attraction that, on histheory, combines with the original repulsive power to determine the basic quantityof matter. It is important here to distinguish which quantities are proportional towhich others, and which are functions of which others, since proportions aresymmetrical (strictly, they are convertible) relations, while functions are asymmetri-cal (non-convertible) dependencies. On Kant’s view, density and volume arefunctions of the original repulsive and attractive forces. However, gravitationalattraction cannot be identified with the original attractive force that helps constituteany quantity of matter. This is because, to retain the Newtonian equation,gravitational attraction is a function of density and volume, while density andvolume are functions of the absolute values of both of the original attractive forceand the repulsive force. Therefore, gravitational attraction cannot be identified withthe original attractive force that constitutes any quantity of matter. This is becausethe original attractive force is only one of the two forces of which gravitationalattraction is a function. Consequently, gravity is not an “original” force of matter;it is a “derivitive” force, deriving from and dependent on the two supposedfundamental forces of original attraction and original repulsion. The problem withthis result for Kant is that

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Kant sought to improve on Newton’s official agnosticism about whether gravity isessential to matter. Kant thought he could show that Newtonian principles requiredascribing gravity directly and essentially to matter, and in the MAdN Kant tried toshow this. However, his proof requires that gravity is the one and only fundamen-164

tal (or “original”) attractive force essential to matter. The problem of circularity inhis anlysis of density shows that he cannot maintain this identity. Consequently,Kant’s argument in “Dynamics” fails of one of its main aims. This largely confirms,thought also modifies, Adickes’s original 1911 conclusion that Kant can only avoidthe problem of circularity by distinguishing two kinds of fundamental attractiveforce. (I disagree with Adickes, for the reason just given, that gravity can still becounted as a fundamental force.) However, this reconfirmation relies solely on theconcepts at issue within Kant’s “Dynamics;” it does not require the spurious appealto Kant’s definitions of mass and of the quantity of matter that is central toAdickes’s formulations.

Density is central to Kant’s problem because Kant sought to explain how equalvolumes of different basic matters could differ in density. As shown above, he canonly do this by rejecting his view in the MAdN that the basic power of attraction isthe same in all materials. Thus is it understandable that Kant should focus on densityin his note and in his letter to Beck (PASSAGES I and II), and not on mass (asAdickes does in his formulations). However, Kant’s problem with density directlyraises the problem of circularity, since solving the problem of density requiresadmitting that the original power of attraction differs in different materials just asdoes the power of repulsion. Once this is admitted, it is virtually impossible not torecognize that gravitational attraction is a function of both of these powers. Hencethe problem of density broaches the problem of circularity, which requiresdistinguishing two different kinds of attractive power, and demoting gravity to aderivitive power. Recognizing these points requires rejecting the theory of matterpropounded in the MAdN, and along with it the metaphysical method undergirdingthat theory (see §VI).

A closely related implication is worth noting here. Within Kant’s theory ofmatter in the MAdN, the basic constitutive power of repulsion is a superficial force,and it is exactly counter-balanced by the power of attraction at the spherical limit ofthe volume of any basic matter. The power of repulsion is effective only in contact,and its effectiveness is neutralized outside the spherical limit of the basic matter.Consequently, Kant must introduce yet another attractive force to account for thecohesion of pieces of matter that comprise a plurality of basic material parts.165

Hence Kant’s remarks about the importance – especially given his overall theory ofmatter – of the questions of cohesion and rigidity.166

The failure of Kant’s theory of matter in the MAdN to account for density is avery serious set-back for his dynamism. Kant recognized that a major support ofcorpuscularism lay in its apparently simple account of density. According tocorpuscularism, all material bodies consist of microscopic material corpuscles,

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which are absolutely dense and rigid, interspersed with varying proportions ofvacant interstices. Kant recognized that to undermine corpuscularism it sufficed167

to provide a theory of matter that could account for density without appealing tohypothetical vacant interstices. He claimed that his dynamic theory of matter did justthat, and that his theory provided a better basis for physical research. Unfortu-168

nately, as Kant came to see in 1792, in PASSAGES I and II, the dynamic theory of theMAdN cannot account for density at all. Kant’s dynamic theory can only accountfor density by admitting that there are two distinct powers of attraction, and thatgravity is a derivitive, not a fundamental, power. As Adickes showed, Kant explicitlydistinguished two kinds of attractive power in 1775–77 (about 10 years before theMAdN), in Reflexion 44 of the Reflexionen zur Physik und Chemie, where he distin-guishes between basic constitutive power of attraction, which he ascribes to theaether, and gravitational attraction. Kant mentions the aether only occasionally in169

the MAdN, and it plays no constitutive role in his published theory of matter. Thisis no accident. For reasons I examine below (§VI), Kant’s constructive metaphysicalmethod cannot admit more than two fundamental forces, one attractive and onerepulsive.

However, admitting two kinds of attractive power and demoting gravity to aderivitive status doesn’t solve the other problem I have stressed, namely that Kant’sdynamically characterized points generate material spheres which cannot compoundwithout either interstices or severe and speculatively unlimited distortion. Whatevermay have been Kant’s influence on the development of field theory, Kant’s dynamicconception is not a field concept, since it is based on individual points in space.Kant must rely on points in space if he is to retain any hope of basing his dynamicsin his transcendental epistemology. The connecting link between them is theempirical concept of matter as the movable in space, which Kant treats as a pointultimately imbued with dynamic powers. To sever that connection would require170

replacing the MAdN with an entirely different link between the general metaphysicsof the first Critique and empirical physics. However, Kant must give up his relianceon points in space imbued with causal powers if he is to maintain his view thatmatter is essentially continuous rather than discrete. Ultimately Kant was forced171

by these problems to forge an entirely different link between transcendentalphilosophy and physical science. To show why, I now turn to the systematicramifications of Kant’s problems with the MAdN.

VI. THE SYSTEMATIC RAMIFICATIONS OF KANT’S PROBLEMS WITH THE MADN.

Each of the two problems with Kant’s “Dynamics,” his fallacious introduction offorces and the circularity in his definition of the quantity of matter, reflect adverselyon Kant’s metaphysical method in the MAdN. Their combined effect is to show thatKant’s metaphysical method is untenable. Though his analysis of pure kinematicsin “Phoronomy” remains intact, at the very least he

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needs an entirely new link between it and dynamic forces, and a new way of basinga theory of matter on those forces. Let’s see why.

The fact that Kant must distinguish gravity from his basic attractive force, andthe serious prospect that he must posit yet another attractive power to account forcohesion, reflects adversely on Kant’s constructive metaphysical method. For all ofhis qualifications on the metaphysical constructability of the concept of matter, andon his own constructions of it, Kant claimed it sufficed for his purposes to presentthe filling of space as a dynamic property of matter. Kant’s “presentation,” his172

metaphysical construction, brings the categories to bear on the forms of intuition,in connection with the elementary empirical concept of matter as the movable inspace. (See §III above.) Kant contends that these constructive grounds suffice todemonstrate that only two basic moving forces of matter are possible. Thisconclusion, Kant argues, follows from the fact that matter can be treated as amoving point, and that two points can only move in two directions with regard toone another; they can either approach or recede from one another. Each kind ofbasic motion is accounted for by each kind of basic force, attraction and repulsion.Consequently, Kant infers, only these two fundamental forces are conceivable.173

Once Kant is forced to acknowledge that gravity is distinct from his basic attractiveforce, because gravity is a function of that basic force plus the basic repulsive force,it is evident that Kant’s quasi–geometrical reasons for maintaining that there can beonly two fundamental forces are specious. This is because his basic argument forthere being only two basic kinds of force turns on the two possible alterations ofspatial relation between two basic matters; they can either approach or recede fromone another. Each basic force is supposed to account for one of these basic relativemotions. However, the power of attraction between bodies, even if those bodies areKant’s basic “matters,” is gravity, yet gravity must ultimately be distinct from the(alleged) basic power of attraction said to be constitutive of the very possibility ofmatter. Resolving the circularity in Kant’s analysis of density thus severs the relationbetween his argument to show that there can be only two fundamental forcesconstitutive of matter and his arguments to show that those fundamental forces arebasic forces of attraction and repulsion.

VII. A FURTHER CIRCULARITY IN KANT’S ARGUMENT.

My first main objection to Kant’s dynamic analysis of matter (§IV) is this: Theinvalidity of Kant’s proof of the first Proposition of Dynamics, that matter fillsspace by virtue of its moving force of repulsion, shows that considerations ofPhoronomy, of pure motions, do not suffice to justify ascribing forces to motions;certainly not within the constraints of Kant’s a priori metaphysical constructions.

This point can be reinforced by noticing a further circularity in Kant’s argument.Kant’s explication of matter in the third chapter, “Mechanics,” that matter is themovable in so far as it possesses moving force, presupposes his 174

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explication in “Dynamics,” that matter fills space by virtue of its moving force.175

However, examining his justification for the Mechanical explication of matter showsthat he implicitly appealed to Mechanical considerations in his proof of the firstProposition of Dynamics! Kant states that, in contrast to the Mechanical explication,the mere Dynamic concept of matter could regard matter as being at rest. Kant176

insists that nothing movable would have moving force if it were not effective in thespace it occupies in virtue of an inherent force, whether repulsive or attractive,through which alone it can convey motion to other movable things. Kant claims177

that repulsion is an original moving force by which a matter imparts (erteilen) motion,while the force of a moving matter enables it to communicate (mitteilen) motion.178

The problem with this way of distinguishing between the dynamic properties ofstationary matter and the mechanical properties of matter in motion is that,according to Kant’s own phoronomic doctrine, what is at rest and what moves ismerely a function of one’s frame of reference. Kant’s proof of the first Proposi-179

tion of Dynamics may have treated one body as being at rest, but it treated anothermatter as being in motion, impacting on the matter at rest and then reboundingfrom it. As Kant’s Remark on the Mechanical explication of matter shows, neither180

matter would impart motion to the other if they did not both possess an originalrepulsive or attractive force. Only Kant’s analysis of forces of moving matters in181

Mechanics could justify his use and interpretation of the second matter (the one thatmoves) in his proof of the first Proposition of Dynamics. If Kant can distinguishbetween Dynamics and Mechanics by specifying which matters are at rest and whichare in motion, then he cannot appeal to the effect of, or the effects on, a matter inmotion impacting on and rebounding from a matter at rest in his proof of the firstProposition of Dynamics. If he relinquishes the distinction between Dynamics andMechanics based on matters being at rest or being in motion, then he has noindependent Dynamic principles to which to appeal in Mechanical explication ofmatter. In either case, Kant’s constructive metaphysical method fails to demonstrate,by considerations of motion – by constructing the minimal empirical concept ofmatter as the movable in space in accordance with the Categories, forms ofintuition, and Principles of the first Critique – that matter fills space by virtue oforiginal moving forces.

VIII. INTERIM CONCLUSIONS.

Kant admitted that, on the basis of his constructive metaphysical methods, he couldonly suggest possible lines for constructing such important characteristics of matteras density, cohesion, rigidity, or friction. The two problems of circularity show182

that Kant’s metaphysical methods in the MAdN do not even suffice to establish thebasic terms of Kant’s dynamic theory of matter, the two powers of attraction andrepulsion. An analysis of density is essential to Kant’s purposes of opposingcorpuscularism, but his analysis of density shows that gravity cannot be identifiedwith the fundamental constitutive force of

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attraction. Bringing the categories to bear on the forms of intuition and theminimum empirical concept of matter as the movable in space in the way Kantproposes is not sufficient for defining the dynamic “possibility” of matter. Apartfrom Kant’s architectonic views of the relation between the first Critique, the MAdN,and empirical physics he hoped to defend, and of the a priori structure of a rationalscience in general, this metaphysical approach does not appear to be necessaryeither. Kant’s metaphysical method in the MAdN affords no insight into the “innerpossibility” of things, and because its arguments are supposed to be cumulative,183

the failure of his proof of the first Proposition of Dynamics entails that the MAdNprovides no a priori justification of the kind Kant envisaged of any principles ofmechanics, pace Kant’s hope and aim.184

IX. RESOLVING THE PROBLEMS WITH THE MADN.

Two main implications for Kant’s project in the MAdN are evident. First, the failureof Kant’s arguments for introducing forces into his analysis entails that only the firstchapter, “Phoronomy,” escapes unscathed. This is not insignificant, for his analysisof spatial regions and motions there show how to replace Newton’s absolute spacewith a constructive procedure for defining frames of reference. Second, Kant’s185

effort to imitate the mathematical method, so far as possible, with his constructivemetaphysical method must be rejected. Constructive analysis of bodies in motioncannot justify the introduction of basic forces that constitute the “possibility” ofmatter, and (because of the cumulative structure of Kant’s analysis) they cannotjustify principles of mechanics. Forces must be taken as basic.

These problems are a deep blow to the Critical philosophy, for (as Tuschling hasemphasized) Kant claimed that the first Critique was essential for the systematicgrounding of natural science. Now Kant’s constructive metaphysical method,186

explicating the minimal empirical concept of matter as the movable in space inaccordance with the four moments of the Table of Categories and the two forms ofintuition, is just what one should expect in an effort to apply the first Critique tonatural science while maintaining a philosophical claim to a priori analysis. Thefailure of this constructive method would require serious re-consideration of therelevance of transcendental idealism to natural science, and might well requirerevising transcendental idealism itself. Thus it is no surprise that Kant only madeone crucial step after several years of reflection. Presumably Kant saw the criticalreview of the MAdN in 1787. We know he discovered the circularity in hisdefinition of the quantity of matter around January 1792. Not until the third quarterof 1798 did Kant take the decisive step that resolves both the question-beggingproof of the first Proposition of Dynamics and the circularity in his definition of thequantity of matter. Kant finally recognized that dynamical principles and theconcepts of force they employ simply cannot be “constructed.” Concomitant with187

this, Kant recognizes that the MAdN only amounted only to Phoronomy. Kant188

now

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demotes mathematics from a model to be imitated in metaphysics to a mereauxiliary aid. This demotion, and its concomitant rejection of the metaphysical189

method of the MAdN, now opens up a “gap” in Kant’s critical philosophy; Kantmust find an entirely new way to relate the system of categories of the first Critiqueto physics. To fill this gap is the main (though reivsed) aim of Kant’s “Transition”project, especially the version set out in the nearly complete manuscript known as“Übergang 1–14.”190

Förster points out that Kant recognized that he must addresss a furtherproblem. As noted above, in the MAdN Kant regarded cohesion as a secondaryconcern. However, he realized in the late 1780's or early 1790's that cohesion isnecessary for the existence of bodies, certainly for the existence of the macro-scalebodies studied by physical mechanics. Because the MAdN provided no account ofcohesion, it provided only an analysis of “matter in general,” and not the “doctrineof body” it had claimed and intended. Hence Kant needed to develop a morethorough analysis of matter in order to provide a metaphysical foundation forphysics.191

As Tuschling has shown, there is no place for Kant’s proposed “Transition fromthe Metaphysical Foundations of Natural Science to Physics” within the frameworkof the classical Critical corpus of the three Critiques plus the Prolegomena andMAdN. Hence the very fact that Kant contemplates a “Transition” at all indicates192

that he thinks something is seriously wrong with the Critical Philosophy. Three basicproblems confronting transcendental idealism that stem from the problems with theMAdN discussed above may be briefly indicated. First, recall Tuschling’s point thatthe MAdN formed a test case for applying the systematic organizing principles ofthe first Critique to natural science. Second, Eckart Förster and Karen Gloy havepointed out that the Schematism of the first Critique only considers time, but omitsspace. The MAdN, in effect, complete the schematism by bringing the categories tobear on outer intuitions. Finally, I have argued elsewhere that the principle Kant193

actually needs in the Analogies of Experience is not the general causal principle thatevery event has a cause, but the specifically metaphysical principle that everyphysical event has an external cause. Kant only formulates this distinction, and he194

only defends this specific metaphysical principle, in the MAdN. The utter failure ofthe MAdN to justify forces, and the consequent reduction of the MAdN toPhoronomy, entails that Kant’s Critical system has no adequate justification of anyof these three crucial doctrines. This marks a very serious shortcoming of Kant’stranscendental idealism. Thus it is not surprising that “idealism” and Kant’sarguments for it (primarily in the Transcendental Aesthetic and the first Antinomy)play an ever diminishing role in the opus postumum. Kant’s shift toward realism isfurther supported by the point emphasized by Buchdahl and Philip Kitcher, that thetenable portions of Kant’s views on the systematic principles of science are quiteindependent of his idealism.195

Kant came to see that the mathematical expression of forces presupposes thoseforces as fundamental, because those forces are necessary for the means

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of measurement through which alone their mathematical relations can bedetermined. Quantities of force and matter can only be determined by measurement.Yet the very existence and functioning of instruments of measure, such as balancescales, presuppose dynamic forces, such as cohesion, in order that those instruments(and their parts) have a form and function at all. Forces are basic. This leads Kant196

to develop a transcendental argument for realism–-for the reality of forces and theirfields. The existence of a continuous dynamic field of physical forces is conditionallynecessary for the possibility of self-conscious experience, but its reality is no longermerely “empirical reality.” This is Kant’s new “transcendental dynamics.” Its197

implications for the analysis of ourselves as knowing subjects stem from thinkingthrough the implications of Kant’s basis for regarding moving force as thefundamental property of matter. His reason for this is that only by its moving forcecan matter affect our sensory organs. If this is so, then our sensory organs must198

themselves be (at least in part) material causes. Eckart Förster has shown that alongwith Kant’s transcendental dynamics comes (ca. August 1799–April 1800) a newdoctrine of “self-positing,” according to which we can only identify perceptibleobjects in space if we first identify ourselves as physiological beings who are centersof active force. We perceive ourselves and objects through our dynamicinteraction.199

These are very surprising, and surprisingly naturalistic, doctrines, especially forthose accustomed only to the “classical Criticism” of the three Critiques. It is not myaim to explore them further here. My only aim has been to show that these quite200

surprising doctrines are legitimate responses to genuine problems infecting theCritical epistemology. Michael Friedman has recently criticized Tuschling’s andFörster’s analyses. I close my defense of their interpretation of Kant’s late work witha brief reply to Friedman’s objections.

X. CRITIQUE OF FRIEDMAN.

Friedman aims to understand Kant’s claim, in both the first Critique and in theProlegomena, that the understanding prescribes laws to nature. To do so he201

interprets the Transcendental Analytic of Kant’s first Critique in terms of MAdN,and the MAdN in terms of Newtonian science. According to Friedman, the threelaws of motion defended in Kant’s third chapter, “Mechanics,” realize the principlesof the three Analogies of Experience by specifying their application to the empiricalconcept of matter as “the movable in space,” thereby schematizing them sufficientlyto apply to objects of experience. Kant’s MAdN replaces Newton’s postulates of202

absolute space and time with a procedure, adapted from Newton’s Principia BookIII, for constructing frames of reference from regions of space and motions ofbodies within them. Within Kant’s procedure, the law of gravity has a mixed203

status because it is derived from a priori laws of the understanding (specifically theprinciples of the Analogies) and of sensibility (Euclidean geometry) together withthe empirical data of experience (Tycho and Kepler). The immediacy and204

universality of

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gravitational attraction are not merely empirical properties of matter knowninductively; they are necessary presuppositions for determining the true motions ofmaterial bodies, and hence are conditions for the possibility of objective experienceof them.205

Friedman’s reconstruction cannot represent Kant’s position or argument. First,even if the MAdN serves as a schematism of the Categories with respect to outerintuition, Kant’s Analogies of Experience cannot be so closely tied to or dependentupon Newtonian physics as Friedman repeatedly insists. The principles of theAnalogies are jointly necessary to identify co-existing objects, objects that move, andobjects that undergo non-spatial changes of state; indeed, they are necessary to206

determine even the apparent time series in our sensory apprehension. Conse-207

quently, applying these principles is necessary in order first to identify planets andtheir apparent motions, or even our instruments and records of astronomicalobservation. These principles are necessary for collecting Tycho’s data and forformulating Kepler’s laws, on the basis of which alone Newton was able to develophis gravitational theory. The laws of motion may be necessary for distinguishing truefrom apparent motions, but they are not and cannot be required for applying theprinciples of the Analogies in order to make self-conscious experience of objectspossible. One must be very careful interpreting Kant’s use of the term “experi-208

ence;” sometimes it concerns self-conscious experience of spatio-temporal objects,sometimes it concerns a systematically organized whole of empirical knowledge. Theformer sense is prominent in the Analogies of Experience; only the latter can be atissue in the final chapter of the MAdN, “Phenomenology.” Friedman conflatesthem.209

Second, Friedman’s interpretation of the MAdN ignores Kant’s metaphysicalmethod. The only empirical element in the MAdN is supposed to be the empiricalconcept of matter as the moveable in space; Kant’s further specification of this210

concept is to be entirely a priori. Friedman’s version of Kant’s reconstruction of211

Newton has Kant appealing to Tycho’s data about planetary orbits, and mountingan a posteriori “boot-strap” argument (in Glymour’s sense) for the immediacy anduniversality of gravitational attraction, which Friedman calls a transcendentalargument. If Kant made such an argument in the MAdN, he was not entitled to212

it, and he would be guilty of inverting the very priority of metaphysics over physicswhose legitimacy and fruitfulness he sought to establish.

My charge may seem incredible; its validity can bee seen by noting Friedman’sshifting treatment of this issue. In his first “briefest sketch” of the relation betweenKant’s philosophy of science and Newton’s physics, Friedman noted that Kant’sthree Laws of Mechanics are supposed to follow from the Principles of theAnalogies of the first Critique together with the metaphysical explication of “theempirical concept of matter” developed in MAdN. He also contends that the laws of213

fundamental forces, and in particular, the law of universal gravitation, is supposedto follow from the analyses of the first

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Critique and the MAdN, in conjunction with the empirical regularities formulated inGalileo’s and Kepler’s laws. This much, I believe, is correct. The problem is that214

even in this preliminary essay, in which he recognizes the Kant’s methodologicalrestriction of the scope of his metaphysical foundations of natural science to theexplication of the empirical concept of matter, Friedman says:

Now, if I am not mistaken, it is just this Newtonian procedure for constructing thecenter of mass frame of the solar system that Kant has in mind in the final chapter(Phenomenology) of [the MAdN], a chapter whose subject is the transformationof appearances [Erscheinungen] into experience [Erfahrung]. Kant begins with thepurely relative motions which, as such, are so far merely appearances . . .215

Friedman mistakes the subject of Kant’s chapter on “Phenomenology.” To be sure,Kant does have Newton’s procedure in mind, but Kant’s chapter treats the“metaphysical foundations of phenomenology,” as is stated in the full title to thechapter. This is to say, Kant purports to treat the metaphysical principles requiredfor transforming appearances into experience, or for distinguishing true fromapparent motions, but he does not undertake that transformation itself, because he cannot,given his restriction of the MAdN to the metaphysical analysis of the empiricalconcept of matter. Friedman’s effort to insert that “transformation” into Kant’schapter on “Phenomenology” is a forced fit. Thus it is little surprise to find hiseffort to do so in this first “briefest sketch” superceded by an extended (and veryinteresting) analysis of Prolegomena §38, which was then incorporated into his book.216

One important thing to note, however, is that the Prolegomena was published in 1783,three years before the MAdN. Only in the MAdN does Kant propound his Criticalmetaphysical method; in Prolegomena §38 Kant need not restrict himself to explicatingmetaphysically the mere empirical concept of matter. In Kant and the Exact SciencesFriedman admits the following:

There is a serious problem facing [my] reconstruction of Kant’s procedure [in theMAdN], however. For the most interesting and important step in this reconstruc-tion – the step that proceeds from the observable (Keplerian) relative motions inthe solar system to the law of universal gravitation and the center of mass frameof the solar system, as in [Newton’s] Principia, Book III – does not explicitly occurin Kant’s text. In fact, although Kant refers to Newton’s Scholium to theDefinitions, he does not explicitly refer to Book III at all in the [fourth chapter,]Phenomenology. (149)

Given Kant’s methodological restriction in the MAdN to the a priori analysis of theempirical concept of matter, one should expect that Kant does not take the stepFriedman thinks is missing from Kant’s chapter on Phenomenology.

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Because that step requires appeal to empirical data, that step has no place in theMAdN. Perhaps that step can be admitted in Prolegomena §38, and it is no surprisethat Friedman turned his attention there. What is surprising, is that nowhere in Kantand the Exact Sciences does Friedman mention or refer to the methodologicalrestriction of the MAdN to which he himself referred in his first “briefest sketch,”namely, that the MAdN can only explicate a priori the empirical concept of matter; noempirical data are thus admissible. Because he ignores this restriction, Friedman’sreconstruction of Kant’s procedure in the MAdN is fundamentally flawed. Friedmanignores Kant’s strenuous warning in the Preface to the MAdN not to mix theboundaries of distinct “sciences.” Of course Kant has Newton’s derivations and217

their problems in mind – and much of what Friedman says about the particulars ofKant’s concerns is of great interest – but Kant does not provide a metaphysicalalternative to Newton’s derivations within the MAdN; he simply analyzes themetaphysical principles he thinks are provided by the Critical philosophy and arerequired by some such derivation, the likes of which he may have sketched inProlegomena §38. But if he did sketch such derivation in the Prolegomena, then heoverstepped the bounds of the Critical philosophy in order to illustrate theapplication of his Critical principles (which were not fully developed then, prior tothe publication of the MAdN) to empirical physics proper.

Against Tuschling and Förster, Friedman charges that Kant’s supposed problemwith the circularity in his definition of the quantity and density of matter cannot beof great importance to Kant’s “Transition” project because the circularity is notmentioned in the opus postumum. Friedman claims that Kant’s distinction between218

mathematical and dynamical moving forces is instead to be understood in thecontext of the debate “between the corpuscular or mechanical natural philosophyand the Newtonian natural philosophy.” According to corpuscular theory, forces219

are only the effect of motion imparted from without; on “Newtonian” theory, forcesinternal to bodies are the cause of their relative motions. Friedman is surely right220

that this historical context is important to understanding Kant’s coming todistinguish mathematical from dynamical moving forces. However, Kant indicatesthat this is the context of his view of the relation between mathematics andmetaphysics in the General Remark to “Dynamics,” in which he compares andcontrasts the corpuscular and dynamic hypotheses. Merely citing this generalscientific context does not explain why Kant modeled metaphysics on mathematicsin the MAdN (1786), and why in 1798 he rejected the mathematical model;Friedman provides no reasons against Tuschling’s and Förster’s original contentionthat making this distinction is necessary to solve a crippling circularity infectingKant’s theory of matter in the MAdN. He also provides no reasons againstTuschling’s and Förster’s original contention that this distinction enables Kant toformulate the problem facing his fallacious argument for the first Proposition ofDynamics, that is, his problem with introducing forces on the basis of motions. Thebootstrap argument Friedman attributes to Kant to show that gravity is an essential

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property of matter would, of course, by-pass these problems, and this seems to bewhat Friedman has done. However, for the reasons given above, Kant cannotpropound such an argument within the methodological constraints of the MAdN.Friedman doesn’t come to grips with those problems because he disregards Kant’smetaphysical method in the MAdN.221

Apart from Kant’s general aim to show that gravity is an essential property ofmatter, Friedman disregards Kant’s theory of matter in the MAdN, too.222

Consequently, Friedman is in no position to justify his (mistaken) claim that the opuspostumum merely extends Kant’s theory of matter by addressing points left open inthe MAdN concerning cohesion, solidification, chemical forces, magnetism, etc.223

Kant must reconsider at least the problem of density, once he saw that his theoryof matter in the MAdN could not account for density at all.

Friedman treats Kant’s proposed “Transition” project instead in view of twomain problems: How can the experimental sciences of chemistry or heat besystematic and be integrated with mathematical physics? and, How can the “top224

down” constitutive procedures of the Transcendental Analytic and MAdN becoördinated with the “bottom up” reflective procedures of scientific investigationanalyzed in the Transcendental Dialectic and Third Critique? Without a guaranteethat these two approaches converge, there is a serious “gap” in Kant’s Criticalphilosophy. These are genuine issues, to be sure, but Friedman gives inadequate225

evidence that these are the issues driving Kant’s explorations in the opus postumum,and in particular in “Übergang 1–14.” First, his sole evidence that Kant is concernedabout coördinating regulative with constitutive procedures is Kant’s mention ofprinciples that are both regulative and constitutive. Yet Friedman doesn’t consider226

the fact that in the Critique of Pure Reason the distinction between constitutive andregulative principles is already problematic, for Kant ascribes a regulative role to thesupposedly constitutive principles of the understanding that are defended in theAnalogies. Second, Friedman does not address the point highlighted by Förster,227

that Kant first speaks of the purported “gap” in the Critical system in directconnection with divorcing metaphysics from mathematics. Third, Friedman’s228

stress on these principles that are both regulative and constitutive is at odds with the“top down” constitutive procedure Kant repeatedly ascribes to his proposedÜbergang. Friedman’s interpretation makes it puzzling why Kant focuses on229

physics and repeatedly formulates his project in terms of a transition to physics, andthat he keeps stressing the “tendency” of the MAdN towards “physics,” and that heextensively discusses this tendency and transition to physics without mentioningchemistry or biology. Physics should not be stressed so often or so centrally if theMAdN was tenable and if Kant’s problem was only to relate physics with the othernew physical sciences. Finally, because he pays so little attention to Kant’s230

metaphysical method and theory of matter in the MAdN, and because he is cavalierabout Kant’s doctrines in the first Critique, it is virtually assured that Friedman is inno position to grasp the

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1. Metaphysische Anfangsgründe der Naturwissenschaft (MAdN) 4:470.13–15. Translated by JamesEllington in: Immanuel Kant, Philosophy of Material Nature (Indianapolis: Hackett, 1985). Icite Kant’s works by volume, page, and line numbers (e.g., 4:321.8–12) of the secondedition of the Akademie Ausgabe of Kant’s gesammelte Schriften (Berlin: de Gruyter, 1922f.).On occasion, to avoid ambiguity, I indicate the Akademie Ausgabe as “Ak.” I give the usualA/B designations of the first and second editions of the first Critique. Quotations fromKant’s first Critique (abbreviated “KdrV”) are from Kemp Smith’s translation (New York:St. Martin’s, 1929).

2. MAdN 4:472.1–4.

3. MAdN 4:472.4–7.

4. MAdN 4:473.5–10.

5. In what follows I will not be concerned much with the official links between Kant’sdoctrines in the MAdN and the first Critique. For discussion of those links, see LotharSchäfer, Kants Metaphysik der Natur (Berlin: de Gruyter, 1966), chs. 1–4 and DanielDahlstrom, “Kant’s Metaphysics of Nature” (in: D. Dahlstrom, ed., Nature and ScientificMethod [Washington: Catholic University of America Press, 1991], 271–290).

6. MAdN 4:473.15–22, 473.35–476.4.

7. MAdN 4:473.31–34.

8. MAdN 4:525.7–12.

9. MAdN 4:525.20–24.

10. I adopt the phrase “post-critical” from Eckart Förster, “Kant’s Notion of Philosophy”(The Monist 72 No. 2 [1989], 285–304), 285.

real problems guiding Kant’s thought in “Übergang 1–14,” problems to whichTuschling and Förster have drawn attention, the problems which I hope to havemade sufficiently clear in previous sections of this essay.

XI. CONCLUSION.

Tuschling’s and Förster’s analyses of Kant’s problems and strategies for solvingthem are basically sound, though I have tried to provide some needed refinement.Friedman’s objections to their analyses are unsound. Kant came to recognize thathis Critical epistemology faced some very serious problems. In particular, thedramatic turn he takes in 1798 stems directly from problems he first saw in 1787 and1792. Kant did not forget what he has previously written and argued. On thecontrary, Kant understood the problems facing his Critical epistemology better thanmost of his expositors and would-be defenders. Though incomplete, his efforts toconfront and resolve those problems in the opus postumum deserve far more, andmore careful, attention than they have so far received.231

NOTES

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11. Gerd Buchdahl, “Zum Verhältnis von allgemeiner Metaphysik der Natur undbesonderer metaphysischer Naturwissenschaft bei Kant” (in: B. Tuschling, ed., Problem derKritik der reinen Vernunft [Berlin: de Gruyter, 1984], 97–174), 135. Unless otherwise noted,all references to Buchdahl are to this article.

12. MAdN 4:524.28–29; quoted by Buchdahl, op. cit., 136. On the previous page he quotesa similar remark from the first Critique: “knowledge of actual forces, . . . can only be givenempirically, as, for instance, of the moving forces, or what amounts to the same thing, ofcertain successive appearances, as motions, which indicate [the presence of] such forces”(A207/B252, 3:178.6–9).

13. MAdN 4:534.18; Buchdahl, 137.

14. A167/B209, 3:153.4; Buchdahl, 134.

15. Buchdahl, 137, with reference to the “negative” procedure Kant mentions at MAdN4:524.20.

16. Buchdahl, 137, 138; cf. 101.

17. This is to say, Buchdahl takes refuge in “good hermeneutic principles” according towhich one can best understand an author in terms of later developments (“Kant’s ‘SpecialMetaphysics’ and The Metaphysical Foundations of Science” [in: R. E. Butts, ed., Kant’s Philosophyof Physical Science {Dordrecht: Reidel, 1986; hereafter cited as “Butts, ed.”}, 127–161], 146)to disown Kant’s transcendental idealism and yet to attribute his stripped down tripartiteschema to Kant as “Kant’s view.” (In this regard, Buchdahl is only more explicit than manyof the other commentators, who offer reconstructions as if they were strict interpretations,and who often disown Kant’s idealism.) After all, one of those later developments is therecognition of the untenability of transcendental idealism! While Buchdahl is right that Kantmeans to appeal to linguistic usage (e.g., op. cit., 120, 135), he ignores the fact that Kantthinks that linguistic usage ultimately reflects the a priori categorical structure of thought bywhich we constitute the objects of our experience, in the idealist terms of which alone Kantthought he could explain the necessity of causal principles in application to substances. Ineffect, Buchdahl ascribes to Kant the very view of the dependence of our conceptualcategories on language that Hamann developed to oppose Kant’s transcendental idealistcritique of “pure” reason! (For a brief discussion of Hamann’s “meta-critique,” see F. C.Beiser, The Fate of Reason [Cambridge, Ma.: Harvard University Press, 1987], 37–43; for moredetails see Robert E. Butts, “The Grammar of Reason: Hamann’s Challenge to Kant”[Synthese 75 {1988}, 251–83].) I have criticized Buchdahl’s broader efforts to reconstructKant’s transcendental idealism in “Noumenal Causality Reconsidered” (forthcoming).Proper hermeneutic principles require calling a reconstruction a reconstruction, especiallywhen it is so selective. Compare our treatments of Kant’s proof of the law of inertia;Buchdahl, Metaphysics and the Philosophy of Science (Oxford: Blackwell, 1969), 674–78, Kant andthe Dynamics of Reason (London: Blackwell, 1992), 32–34, 36, 89–90, 282–83, 301; K. R.Westphal, “Kant’s Proof of the Law of Inertia” (in: H. Robinson, ed., Proceedings of the 8th

International Kant Congress, 1995).

18. Gordon Brittan, Jr., “Kant’s Two Grand Hypotheses” (in: Butts, ed., 61–94), 89. Unlessotherwise noted, all references to Brittan are to this article.

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19. Ibid., 89–90.

20. Ibid., 90–91.

21. Ibid., 72.

22. MAdN 4:517.18–35.

23. Robert E. Butts, “The Methodological Structure of Kant’s Metaphysics of Science” (in:Butts, ed., 163–199), 188. All further references to Butts are to this article.

24. Ibid., 188, 194–195.

25. MAdN 4:534.20–26.

26. Howard Duncan, “Kant’s Methodology: Progress Beyond Newton?” (in: Butts, ed.,273–306; cited hereafter as “Methodology”), 287.

27. “Kant on Realism and Methodology” (in: Butts, ed., 305–329), passim.

28. Ibid.. She follows Brittan (Kant’s Theory of Science [Princeton: Princeton University Press,1978], 122) regarding Kant’s aim to provide a realist interpretation of Newton (op. cit., 315).

29. “Methodology,” 288.

30. Ibid., 288f., and “Constructions and their Discovery” (in: G. Funke & Th. Seebohm,eds., Proceedings of the Sixth International Kant Congress [Lanham, MA: University Press ofAmerica, 1989], 83–95), esp. 92.

31. “Methodology,” 299; citing KdrV A727/B755f..

32. “Methodology,” 298.

33. See “Methodology”, 285; cf. Brittan’s criticisms of Duncan in “Kant’s Two GrandHypotheses” (op. cit.), 85–86.

34. MAdN 4:525.7–12.

35. MAdN 4:524.40–525.7.

36. MAdN 4:525.20–21.

37. MAdN 4:518.25–31, 522.39–523.4, 525.26ff.

38. These points about Kant’s qualifications of his admission that he cannot fully constructthe dynamic concept of matter, and his insistence that it suffices to construct the two basicforces of his dynamic theory, bear in a particular way on Duncan’s interpretation. Duncantakes Kant’s admission to be unrestricted, and he contends that Kant can defer construc-tions until whenever someone more adept might devise them. This cannot be right, forKant vigorously sought to establish the basic terms of his dynamic theory in order toopposed corpuscular atomism. If he cannot construct even the two basic forces of hisdynamic theory, then he simply has no alternative theory to offer in opposition tocorpuscularism. In a very interesting treatment of the relation between Kant’s chapters

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on “Dynamics” and “Mechanics,” Duncan contends that Kant ultimately treats the laws ofmechanics in purely kinematic terms because, on the one hand, he cannot construct hisdynamic concept of matter, and on the other hand, his main aim was to justify mathemati-cized physics (“Inertia, The Communication of Motion, and Kant’s Third Law ofMechanics” [Philosophy of Science 51 {1984}, 93–119). Duncan fails to note the bitter ironythis position would involve for Kant. If he were forced to treat mechanical laws in purelykinematic terms because he couldn’t construct his dynamic concept of matter, then hewould not only have abandoned his dynamism, but would have adopted the main tenets ofhis opponents, the “mathematical students of nature.”

39. MAdN 4:467.2–16.

40. MAdN 4:471.11–32, 542.12–543.14; cf. A381, 4:238.35–239.13; B291–93, 3:200.6–201.-15; B293–94, 3:201.30–35. These latter passages should be considered in connection withthe first Paralogism in each edition. I discuss this in “Kant’s Critique of Determinism inEmpirical Psychology” (forthcoming).

41. MAdN 4:471.32–37.

42. MAdN 4:476.9–12.

43. MAdN 4:476.12–477.2.

44. MAdN 4:473.6–8.

45. MAdN 4:472.27–32.

46. MAdN 4:472.32–35.

47. MAdN 4:472.36–473.5.

48. MAdN 4:470.13–15.

49. MAdN 4:472.1–4.

50. MAdN 4:472.4–7.

51. MAdN 4:473.5–10.

52. MAdN 4:467.18–19.

53. MAdN 4:468.13–17, 469.12–14.

54. MAdN 4:468.19–23.

55. MAdN 4:468.23–29.

56. MAdN 4:469.26–33, 475.31–32.

57. MAdN 4:477.14–17.

58. MAdN 4:470.18–19.

59. MAdN 4:470.19–23.

60. MAdN 4:470.23–26.

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61. MAdN 4:470.25–26.

62. MAdN 4:470.26–27, 469.21–25. For an outstanding discussion of Kant’s views on thesynthetic, constructive nature of mathematical knowledge, see Michael Friedman, Kant andthe Exact Sciences (Cambridge, MA: Harvard University Press, 1992), chapters 2 and 3. Unlessotherwise noted, all further references to Friedman are to this book.

63. MAdN 4:470.27–32.

64. MAdN 4:478.21–27. Note that Kant did not try to imitate the mathematical method ofdeductive proof. For further discussion of Kant’s metaphysical constructions, and theirdifferences from mathematical constructions, see Schäfer (op. cit.), 30–38.

65. MAdN 4:469.33–70.1.

66. MAdN 4:470.1–12.

67. MAdN 4:472.4–6.

68. MAdN 4:472.7–11, 473.6–10.

69. MAdN 4:472.11–12.

70. MAdN 4:473.15–474.2.

71. MAdN 4:473.2.

72. MAdN 4:474.2–476.4.

73. MAdN 4:476.7–12, 480.6.

74. MAdN 4:536.5–7.

75. MAdN 4:554.5–7.

76. MAdN 4:477.3–13.

77. MAdN 4:561.3–11f.

78. A182, VI 124.20–22; B224, 3:162.5–6; A189, VI 128.26–27; B232, 3:166.32–33; A211,VI 141.10–11; B256, 3:180.25–27.

79. MAdN 4:541.28–30, 543.16–17, 544.32–33.

80. MAdN 4:549.4–9ff..

81. MAdN 4:496.5–9, 497.12–13.

82. MAdN 4:497.14–16.

83. MAdN 4:497.23.

84. MAdN 4:487.10–14, cf. 495.24–26.

85. Cf. MAdN 4:493.34–494.1.

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86. MAdN 4:493.26–494.1.

87. Phoronomy abstracts from causal considerations: MAdN 4:480.15–18, 486.36–487.10,489.14–20, 492.15–18, 493.11–14, 494.5–14, 494.28–38; Phoronomy treats solely thequantitative aspects of motion, direction and velocity: 483.26–28, 484.36–37, 489.11–12;Phoronomy treats the quantitative combination of motions: 489.14–20.

88. MAdN 4:488.26–31, 495.5–12. If Kant were not anticipating the application of hisphoronomic analysis to actual motions of physical bodies, he would have no grounds forfocusing on rectilinear or even curvilinear motions, as contrasted with, e.g., triangularmotions or just plain random ones.

89. These are the three cases Kant treats in his proof of the Phoronomic Proposition,MAdN 4:490.15–16, 491.11–13, 492.1–3.

90. Cf. MAdN 4:490.28–30.

91. MAdN 4:490.7–13, 493.14–24, 494.1–14, 494.28–495.3.

92. MAdN 4:481.12–25, 481.28–37, 482.3–6, 487.22–29, 488.1–7, 488.15–17.

93. Cf. MAdN 4:490.8–13.

94. MAdN 4:487.15–20.

95. MAdN 4:489.6–12.

96. Cf. MAdN 4:487.10–11.

97. MAdN 4:489.2–4, 489.17–18, 489.21–25.

98. MAdN 4:489.14–20, 492.15–18, 493.11–14.

99. MAdN 4:486.30–34, 489.1–4; cf. 486.36–487.4, 489.14–20.

100. MAdN 4:493.14–24.

101. Each of the component motions must last the whole elapsed time, for as soon as oneof the component motions ceases, so does the combination of that motion with any othermotion.

102. MAdN 4:490.15–34.

103. MAdN 4:491.17–21.

104. MAdN 4:492.1–18.

105. By “a matter” Kant here means a material body, not a kind of matter.

106. “A Response to Burkhard Tuschling’s Critique of Kant’s Physics” (Kant-Studien 79[1988], 57–79), 70. He cites Tuschling, Metaphysische und transzendentale Dynamik in Kants opuspostumum (Berlin: de Gruyter, 1971; cited hereafter as “Met. & tr. Dynamik”), 108.

107. MAdN 4:497.21–23.

108. I think it is virtually certain that they are to be understood as causal terms here.

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Compare Kant’s parallel usage in his essay on negative quantities: “Die Realrepugnanzfindet nur statt, insofern zwei Dinge als positive Gründe, eins die Folge des andern aufhebt”(II 175.34–35); “Man versuche nun, ob man die Realentgegensetzung überhaupt erklärenund deutlich könne zu erkennen geben wie darum, weil etwas ist, etwas Anderes aufgehoben werde,und ob man etwas mehr sagen könne, als was ich sagte, nämlich lediglich, daß es nichtdurch den Satz des Widerspruchs geschehe” (II 203.32–36). Cf. “Der einzig möglicheBeweisgrund zu einer Demonstration des Daseyns Gottes” (II 86.5–15).

109. Kant’s formulation is quoted above, p. 15.

110. This general conclusion was already reached by Erich Adickes (Kant als Naturforscher[Berlin: de Gruyter, 1924–1925], §75, vol. I, 188) and conceded by August Stadler (KantsTheorie der Materie [Leipzig: Hirzel, 1883], 67–69).

111. MAdN 4:492.14–18.

112. MAdN 4:497.24–26.

113. MAdN 4:493.14–24, 494.5–14, 494.28–38.

114. MAdN 4:493.21.

115. MAdN 4:494.6–7, 494.31; note that Kant stresses “external” in this second passage.

116. MAdN 4:497.26–28.

117. MAdN 4:497.19–21, 497.24–26; quoted above, p. 17.

118. MAdN 4:498.3–5.

119. A similar argument to the same conclusion is made by Adickes (Kant als Naturforscher,op. cit., I, 188–190).

120. Anonymous review in Göttingische Anzeigen von gelehrten Sachen No. 191 (December 2,1786; 1914–1918), 1915–16; reprinted in: Albert Landau, ed., Rezensionen zur KantischenPhilosophie 1781–87 (Bebra: Albert Landau Verlag, 1991), vol. I, 497–481; 480; my tr..Landau claims that A. G. Kästner is the author (ibid., 776); Tuschling quotes this passagefrom the review and offers persuasive evidence that the author was J. T. Mayer (Met. & Tr.Dynamik, 47–49). Adickes does not cite this review either in his German Kantian Bibliography(rpt. New York: Burt Franklin, 1970), or in Kant als Naturforscher (op. cit.).

121. XXI 415.2–17. G. Lehmann, the editor, quotes the relevant paragraph of the review(XXII 809).

122. Met. & tr. Dynamik, 39–47.

123. Kant als Naturforscher, op. cit., I, 190.

124. XXI 415.6–8. Tr. by E. Förster & M. Rosen, Kant’s Opus Postumum (Cambridge:Cambridge

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University Press, 1993), 3.

125. Eckart Förster refers to Kant’s letter to Beck, Adickes’s editorial apparatus, and toTuschling, and he accepts Adickes’s formulation of the problem (“Is There ‘A Gap’ inKant’s Critical System?” Journal of the History of Philosophy 25 [1987], 536–55; hereafter citedas “Gap?”; 548 note 35). In his splendid introduction to his edition of Kant’s Opus Postumum,Förster restates essentially the same formulation of the problem as he gave in “Gap?” (op.cit., xxxvi). Tuschling refers to Kant’s letter to Beck and to both of Adickes’s discussionsin his editorial apparatus and in Kant als Naturforscher (vol. I, 214–215). Tuschling notesAdickes’s shifting assessment of the circle, and argues against Adickes’s solution on broadsystematic grounds without re-examining the details of Adickes’s analysis or Kant’sstatements of it (Met. & tr. Dynamik, 46f.). Buchdahl refers to Kant’s letter to Beck, and toTuschling, but gives a slightly different formulation of the circle. According to Buchdahl,Kant occasionally assumes the proportionality between inertial and gravitational mass, whilealso assuming that gravitational mass results from attractive force (op. cit., 131). WhileBuchdahl is right that the MAdN has a problem with the distinction between gravitationaland inertial mass, he discusses no texts in this connection. I shall show below that this, too,is not an adequate formulation of Kant’s problem. In his response to Tuschling’s criticismof Kant’s theory of matter in the MAdN, McCall simply ignores the problem of circularity(op. cit.). This mitigates much of the force of McCall’s reply; even if there are the manypoints of continuity of doctrine between the MAdN and the opus postumum that McCallclaims, in view of the fundamental problems with Kant’s theory of matter in the MAdN,those points of doctrine must be established on a quite different basis in the opus postumum.

126. MAdN 4:497.15–16.

127. MAdN 4:510.28–511.12.

128. MAdN 4:497.15–28.

129. MAdN 4:508.27–32.

130. MAdN 4:511.3–11.

131. MAdN 4:511.14–18.

132. MAdN 4:521.7–8.

133. MAdN 4:525.29–30, cf. 526.2–4.

134. MAdN 4:523.21–524.17.

135. Cited by Adickes, Ak. 14:337.18–25, and Kant als Naturforscher §85 (vol. I, 214). Kant’sGerman is as follows: “Die größte Schwierigkeit ist zu erklären wie ein bestimmtes Volumenvon Materie durch die eigene Anziehung seiner Theil[e] in dem Verhältnis des Quadrats derEntfernung inverse bey einer Abstoßung die aber nur auf die unmittelbar berührenden Theile(nicht auf die Entfernten) gehen kan[n] im Verhältnis des Cubus derselben (mithin desVolumens selber) möglich sey. Denn das Anziehungsvermögen kommt auf die Dichtigkeitdiese aber wieder aufs Anziehungsvermögen an. Auch

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richtet sich die Dichtigkeit nach dem umgekehrten Verhältnis der Abstoßung d.i. desvolumens.”

136. Cited by Adickes, Ak. 14:337.29–35, and Kant als Naturforscher §85 (vol. I, 214). Kant’soriginal runs: “Ich würde die Art der Auflösung dieser Aufgabe wohl darin setzten: daß dieAnziehung (die allgemeine, Newtonische,) ursprünglich in aller Materie gleich sey und nurdie Abstoßung verschiedener verschieden sey und so den spezifischen Unterschied derDichtigkeit derselben ausmache. Aber das führt doch gewissermaaßen auf einen Cirkel ausdem ich nicht herauskommen kan[n] und darüber ich mich noch selbst besser zu verstehensuchen muß.”

137. Ak 14:337.15–17.

138. Adickes does not treat the most puzzling stentence of Kant’s initial formulation(PASSAGE I), the last sentence in which Kant worries that density is inversely proportionalto repulsion. I confess that, after concerted effort, I do not have an explanation of thatsentence either, but it is important not to introduce further puzzles in the course ofexplaining Kant’s puzzle! Perhaps Kant’s last sentece is just mistaken, and for that reasonomitted from his letter to Beck. The idea that density would decrease with an increase ofrepulsive force simply makes no sense within Kant’s theory.

139. MAdN 537.11–15, .23–25, respectively.

140. MAdN 536.9–537.4. Kant’s grounds for this are given in the first Proposition ofDynamics and its Proof. These are discussed and criticized above (§IV).

141. I owe most of the points made in this paragraph to Jeff Edwards.

142. MAdN 518.35–519.16.

143. MAdN 4:498.26–499.4, cf. 511.19–26; see §VI for discussion.

144. MAdN 518.12–19, cf. 541.14–15.

145. MAdN 4:521.7–12; cf. p. 18 and notes 126–131 above.

146. E.g., MAdN 4:499.14–15, 499.18, 517.28, 518.21, 524.7–8; Ak XI 1 ed. 348, 2 ed.st nd

361.33 (quoted above, p. 25).

147. MAdN 4:508.18–32.

148. MAdN 4:533.36–534.5.

149. For Kant’s criticisms of physical monadology see MAdN 4:504.10–505.7, 539.32–-540.4. On the tendencies of Kant’s theory of matter in MAdN to revert to atomism ormonadism, see Adickes’s editorial comments (Ak. XIV 338.20–337.10).

150. MAdN 537.12–13.

151. MAdN 4:524.10–12, 524.40–525.7, 525.12–19.

152. MAdN 4:535.5–10; cf. KdrV A172–75/B214–16, 3:155.32–157.18; A214/B261,3:183.8–12.

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153. Kant argues for the continuity (as opposed to the discreetness) of matter by arguingthat matter is potentially infinitely divisible, though it is not actually divided (MAdN4:503.21–504.8). What he overlooks in this argument is that because the strength of boththe fundamental forces diminish with distance, regions of a matter nearer the center of thematter must be more intensively occupied by those forces than regions nearer the peripheryof the matter. Consequently, the density of matter must diminish with distance from thecenter of any matter. Hence any regions divided out of a matter that differ in their distancefrom the center would also differ in density. Hence they would be different kinds of matter!Kant’s view that matter is continuous does not fit with his basic dynamism at all. Forfurther discussion of Kant’s theory of matter, see Rudolf Kötter, “Kants Schwerigkeitenmit der Physik. Ansätze zu einer problemorientierten Interpretation seiner späten Schriftenzur Philosophie der Naturwissenschaft” (in: Forum für Philosophie Bad Homburg, ed.,Übergang. Untersuchungen zum Spätwerk Immanuel Kants [Frankfurt am Main: VittorioKlostermann, 1991; cited hereafter as “Übergang”], 157–184), and Martin Carrier, “Kraft undWirklichkeit. Kants späte Theorie der Materie” (in: ibid., 208–230), and “Kants Theorie derMaterie und ihre Wirkung auf die zeitgenössische Chemie” (Kant-Studien 81 [1990],170–210).

154. MAdN 4:517.18–35.

155. MAdN 4:516.14–26, 517.18–21, 518.17–19.

156. MAdN 4:521.4–5.

157. MAdN 4:516.2–4, 516.9–14, 524.7–10.

158. MAdN 4:521.5–7.

159. Ak XI 2 ed. 361.32–35; quoted above p. 25.nd

160. This is his proposal in MAdN (4:521.7–12).

161. MAdN 4:517.18–518.2.

162. Ak 14:338.2–3; quoted above p. 26. Adickes’s solution (ADICKES 1924B) also invertsthe Newtonian relation: “Once again mass is directly dependent upon the degree ofattractive force,” i.e., mass depends upon gravity!

163. It was developed by Karl Weierstrass in 1841 (Mathematische Werke [Berlin, 1894], vol.I, 67). See Florian Cajori, A History of Mathematical Notations (Chicago: Open Court, 1929),vol. II, p. 123.

164. See Kant’s Proposition 7 of Dynamics, and his second Remark to that Proposition(MAdN 4:512.17–32, 514.11–515.37).

165. Kant contends that cohesion isn’t a fundamental power of matter because it doesn’tbelong to the possibility of matter in general (MAdN 4:518.25–31), it is effective onlybetween basic matters of the same kind of material (and so is only disjunctively, notcollectively, a universal property of matter), it is not always proportional to density, and itseffect depends upon a material undergoing a process of liquification and solidification(MAdN 4:526.12–35). These are plausible reasons for Kant’s contention, but their

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strength is mitigated by the problems facing Kant’s theory of density, which point to theinsufficiency of attraction and repulsion for explicating the possibility of matter in general.Kant defines original properties of matter as essential properties that cannot be derivedfrom other properties of matter (cf. MAdN 4:500.1–6). Kant cannot derive cohesion fromthe other essential properties of matter he enumerates, and its importance for explainingso many common and scientific phenomena may suffice for holding that it is essential. Thismay contravene Kant’s metaphysical grounds for specifying what is essential, namely thatit be a condition for the inner possibility of something (MAdN 4:511.14–15), where this“inner possibility” must be a function of rational elements of knowledge or construction,i.e. the first Critique and the MAdN (MAdN 4:517.36–518.1), but this may be just one moreunsupportable implication of Kant’s metaphysical attempt to ground science.

166. MAdN 4:529.18–25.

167. MAdN 4:525.31–36.

168. MAdN 4:523.21–524.17.

169. Ak 14:334.1–336.1–6. See Adickes’s editorial comments (14:337.2–15).

170. In some notes from the 1770's Kant tries to treat these points as merely heuristic, buteven then he was not able to escape his monadological model.

171. See note 153 above.

172. MAdN 4:522.39–523.4.

173. MAdN 4:498.26–499.4, cf. 511.19–26. Kant concludes his argument by speaking of two“kinds” of force (“Also können nur diese zwei Arten von Kräften, als solche, worauf alleBewegungskräfte in der materiellen Natur zurückgeführt werden müssen, gedacht werden”[MAdN 4:499.2–4]). However, Kant cannot be taken to mean by this that there are twogenera of basic forces, attractive and repulsive, which are instantiated by various species ofeach kind. Kant’s constructive metaphysical method gives him and can give him no basisfor distinguishing among distinct kinds of forces, each of which must be described inidentical metaphysical terms as attractive or repulsive force. Moreover, as argued aboveagainst Butts (§II), Kant intends his two basic forces of attraction and repulsion to beexplanatory, and to be explanatory they must be constitutive, and not merely regulativeheuristic classifications. His initial formulation of his thesis, which precedes his proof,reflects this fact by speaking of forces, not kinds of force: “Es lassen sich nur diese zweibewegende Kräfte der Materie denken” (MAdN 4:498.27); he repeats this language in hisRemark to Lehrsatz 6 (MAdN 4:511.20). The two “kinds of force” must be the two specifickinds, attractive and repulsive, of the single genus, force.

174. MAdN 4:536.6–7.

175. MAdN 4:536.15–537.1.

176. MAdN 4:536.9–12. This circularity (and even more so the one discussed above in §V)is distinct from those referred to and address by Alfred E. and Maria G. Miller in

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their “Translator’s Introduction and Commentary” to their translation of Peter Plaass,Kant’s Theory of Natural Science (Boston Studies in the Philosophy of Science, vol. 159; Dordrecht:Kluwer, 1994). I do not believe that their means for resolving some other apparentcircularities can be extended to the two I develop here, nor do I believe their means aresound. They import Kant’s regressive, transcendental method of proof in the first Critiquedirectly into the MAdN. In the first Critique, a Principle does serve as its own “ground ofproof” because it makes experience possible (A 737=B 765; Miller & Miller, 59). However,precisely because the transcendental principles of the first Critique are (purportedly)established prior to the MAdN (ibid., 60), Kant cannot offer transcendental arguments forthe principles defended in the MAdN. The Millers’ way of contrasting unthematic andthematic aspects of Kant’s analysis (ibid., 59) and their way of emphasizing the internalconsistency and mutual interdependence of the components of Kant’s analysis of themetaphysical foundations of physics (ibid., 61) are not precise enough to distinguishtranscendental, metaphysical, bootstrap, and viciously circular argument. Regrettably, thismatter deserves more attention than I can give it here.

177. MAdN 4:536.15–537.4.

178. MAdN 4:536.13–15.

179. Cf. MAdN 4:538.22–25.

180. MAdN 4:497.18–19, 497.25–26.

181. MAdN 4:536.18–23.

182. MAdN 4:526–527.

183. MAdN 4:511.14–15.

184. MAdN 4:549.4–9ff. This, at least, is the official implication, had Kant argued inaccordance with his method. As Duncan points out, Kant’s justification of his laws ofmechanics is mainly kinematic, and not dynamic (“Inertia, the Communication of Motion,and Kant’s Third Law of Mechanics” [op. cit.]). In view of Kant’s failures, it is worthmentioning one of Kant’s successes. As Buchdahl remarks, Kant succeeds at showing thatthe concept of action at a distance is not absurd. Two further successes, highlighted byFriedman, are noted below.

185. For discussion, see Michael Friedman (op. cit.), ch. 3, esp. 140–143.

186. B109–110, 3: 95.12–23; Met. & tr. Dynamik, 38–39.

187. Ak XXI 286–287; August–September 1798.

188. XXI 164.8–11, 166.29–167.10 (Adickes dates these from September/October 1798;Tuschling from the second third of 1798); cf. Met. & Tr. Dynamik, ch. 5.

189. XXI 482; Förster, “Gap?”, 549.

190. XXI 206–247, 535–612, 512–520, XXII 609–615 (May–August 1799); Förster, “Gap?”,549ff.

191. See Förster’s Introduction to the Opus Postumum (op. cit.), xxxviii.

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192. “Die Idee des transzendentalen Idealismus im späten Opus postumum” (in: Übergang,105–145), 105–109.

193. Förster, “Gap?”, 540–43; Karen Gloy, “Das Verhältnis der Kritik der reinen Vernunftzu den Metaphysischen Anfangsgründen der Naturwissenschaft, demonstriert amSubstanzsatz” (Philosophia Naturalis 21 [1984], 32–63), 38.

194. MAdN 4:543.16–34, KdU V 181.15–31. I discuss this issue in “Does Kant’s MetaphysicalFoundations Fill a ‘Gap’ in the Critique of Pure Reason?” (Synthese, 1995).

195. In addition to the piece by Buchdahl cited above, see his “Neo-transcendentalapproaches towards scientific theory appraisal” (in: D. H. Millor, ed., Science, Belief andBehaviour: Essays in Honour of R. B. Braithwaite [Cambridge: Cambridge University Press,1980], 1–21). Also see Philip Kitcher’s excellent article, “Projecting the Order of Nature”(in: Butts, ed., 201–235). A similar point about systematicity as a criterion of truth is madeby Okruhlik (op. cit., esp. 318).

196. XXI 294.11–26, XXII 259.6–8, Loses Blatt Leipzig 1 (in: Übergang, 152). See EckartFörster, “Die Idee des Übergangs” (in: Übergang, 28–48), 35–36.

197. In addition to Tuschling (op. cit.), see B. Jeffrey Edwards, “Der Ätherbeweis des OpusPostumum und Kants 3. Analogie der Erfahrung” (in: Übergang, 77–104).

198. MAdN 4:476.9–12; discussed above, p. 9.

199. “Kant’s Selbstseztungslehre” (in: E. Förster, ed., Kant’s Transcendental Deductions[Standford: Stanford University Press, 1989], 217–38). For a general discussion, see KurtHübner, “Leib und Erfahrung in Kants Opus Postumum” (Zeitschrift für philosophischeForschung 7 [1953], 204–219; rpt. in: G. Prauss, ed., Kant. Zur Deutung seiner Theorie vonErkennen und Handeln [Köln: Kiepenheuer & Witsch, 1973], 192–204).

200. For further discussion see the articles cited earlier, along with Paul Guyer, “Kant’sEther Deduction and the Possibility of Experience” (in: G. Funke, ed., Akten des 7.Internationalen Kant-Kongress [Bonn: Bouvier, 1991], vol. II.1, 119–132) and Martin Carrier,“Kants Theorie der Materie und ihre Wirkung auf die zeitgenössische Chemie” (op. cit.).There is an excellent bibliography on Kant’s opus postumum in Übergang (op. cit.), 233–244.

201. Friedman, op. cit., 165, 183.

202. Ibid., 46, 136–7, 159, 163–4, 171, 185, 202–3, 234, 255, 259.

203. Ibid., 140–3.

204. Ibid., 167, 177–8.

205. Ibid., 158, 171, 174, 231 note 29, 235.

206. See Paul Guyer, Kant and the Claims of Knowledge (Cambridge: Cambridge UniversityPress, 1987), 168, 212–14, 224–25, 228, 239, 246, 274–75.

207. A199–200/B244–45, 3: 173.34–174.5; quoted below, note 209.

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208. Contra Friedman’s claim that “in order to apply this concept [sc. of matter as themovable in space] we thus need an objective notion of true [sc. Newtonian] motion” (op. cit.,174 note 14) – as if no one had correctly applied the minimal concept of “moving object”prior to learning Newton’s theory! Cf. the passages cited in note 202 above.

209. The strongest case Friedman could make for his interpretation would rest on a passagehe doesn’t discuss, where Kant says (in the first Remark in “Phenomenology”) that “inappearance no judgment at all of the understanding is to be found” (MAdN 4:555.9–10).This statement, however, should be interpreted in its context. Kant here contrastsappearance with illusion, where illusion concerns systematically mistaken judgments where-by something subjective is taken for something objective (MAdN 4:555.6–9). This stronglysuggests that illusion concerns “transcendental illusion,” as analyzed in the Dialectic of thefirst Critique. Kant makes quite plain that “appearances” here concern motions, whichbodies are moving and which are at rest (MAdN 4:554.16–555.5). For this to be at issue, wemust be able to identify and re-identify apparently moving bodies. To do this requires, asargued in the Analogies of Experience, the judgmental application of schematized categoriesto sensory intuitions, in accordance with the Principles of the Understanding. In connectionwith the statement just quoted, Ellington cites a remark in the first Critique that may seemto support Friedman’s view, namely: “It is therefore correct to say that the senses do noterr – not because they always judge rightly but because they do not judge at all. Truth anderror, therefore, and consequently also illusion as leading to error, are only to be found inthe judgment, i.e., only in the relation of the object to our understanding” (A293/B350, 3:234.17–21). However, on Kant’s view, sensation alone does not suffice to produceappearances! Appearances are representations, and representations require both sensationand understanding. Kant is quite direct about this: “Understanding is required for allexperience and for its possibility. Its primary contribution does not consist in making therepresentation of objects distinct, but in making the representation of an object possible atall. This it does by carrying the time-order over into the appearances and their existence.For to each of them, [viewed] as [a] consequent, it assigns, through relation to the precedingappearances, a position determined a priori in time. Otherwise, they would not accord withtime itself, which [in] a priori [fashion] determines the position of all its parts”(A199–200/B244–45, 3:173.34–174.5). As he makes quite plain in the immediatelysubsequent sentences and paragraphs, the time-order at issue here is not an exact orquantitative one pertinent to a debate between Newton and Kepler or even Ptolemy, it isthe minimal sequence of before and after requisite for ordinary experience of objects.(Though Kant’s statement from “Phenomenology” quoted above may seem misleading, Ido not think it is inconsistent with the first Critique, though it needs to be understoodcarefully in its context.)

210. MAdN 4:472.1–12, 480.6.

211. MAdN 4:470.1–12, 477.14–17; KdU V 181.15–31. See §III above.

212. Op. cit., 171.

213. “Kant on Laws of Nature and the Foundations of Newtonian Science” (in: G. Funke& T. Seebohm, eds., Proceedings of the Sixth International Kant Congress [Lanham, MD:University Press of America, 1989], 97–107), 99; Friedman’s emphasis. He describes hisessay as “the briefest sketch” on ibid., 98.

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214. Ibid., 99.

215. Ibid., 103.

216. The original article is “Kant on Space, the Understanding, and the Law of Gravitation:Prolegomena §38" (Monist 72 [1989], 236–84). It appears under the same title as chapter 4 ofKant and the Exact Sciences, 165–210.

217. MAdN 4:472.36–473.14.

218. Ibid., 223 note 13. In his Introduction to the Opus Postumum Förster grants that Kantdoesn’t mention the circle in his analysis of density, but he does claim that it’s easy to seehow Kant’s further attempts to analyze matter propose to avoid the circularity (op. cit.,xxxix).

219. Ibid., 226.

220. Ibid. Friedman persistently errs about the extent to which Newton himself was“Newtonian” in this sense. Newton himself frequently proclaimed his adherence tocorpuscular doctrine and treated gravity merely as a calculative hypothesis rather than as aninherent property of matter. Martin Carrier (“Kraft und Wirklichkeit. Kants späte Theorieder Materie” [in: Übergang, 208–230]), and Hans-Joachim Waschkies (“WissenschaftlichePraxis und Erkenntnistheorie in Kants Opus postumum” [ibid., 185–207]) rightly stress that“Newtonian principles of explanation” at that time meant, not Newtonian laws of motion,but explanation in terms of a postulated geometrical physical microstructure. Also seeBrittan, who directly pointed out Friedman’s error in this regard (“Kant’s Two GrandHypotheses,” op. cit., 75–76 note 19), and Howard Duncan, “Methodology” (op. cit.),273–277.

221. Friedman’s interpretive method is to read Kant’s texts in the context of the history ofscience (cf. op. cit., 231 note 29, 226). This is fine, but such an approach can only serve as abasis for excluding other issues or denying that they are important for understanding a textif that approach provides a complete and adequate reading of the text at issue. However,Friedman’s reading is very selective, and not even adequate within his chosen range of sub-texts, simply because many of the views he ascribes to Kant directly violate Kant’s explicitviews, both methodological and substantive, expressed in the MAdN and the first Critique.

222. At one point Friedman claims that Kant’s main disagreements with Newton do notconcern the theory of matter (ibid., 138), but later he recognizes that Kant criticizes Newtonfor not counting gravity as an essential property of matter (ibid., 228–229).

223. Ibid., 237–240.

224. Ibid., 240, 242.

225. Ibid., 254, 256–7, 262, 304–5.

226. XXII 240.25–28, 241.19; quoted by Friedman (op. cit.), 262.

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227. A180/B222–23, 3:160.34–161.14. Friedman discusses this passage elsewhere, butwithout considering its bearing on his interpretation of the passages cited from the opuspostumum in the previous note (“Regulative and Constitutive” [Southern Journal of PhilosophyXXX Supplement {1991}, 73–102], 75f.). Friedman does cite a related passage (A664/-B692; op. cit., 163), but doesn’t consider it in connection with his claims about Kant’sproblematic in the opus postumum. It will not do to reply that the “Analogies” representregulative principles of the understanding, while the “Dialectic” treats regulative principles ofreason. While true, this distinction is obliterated in the relevant passages of the opus postumumbecause Kant speaks of principles that are both regulative and constitutive withoutdistinguishing reason and understanding at all. Moreover, in “Übergang 1–14" Kant ascribesa constitutive function to a whole of matter actively filling space (an aether), and to a wholeof experience (cf. XXI 217.26–219.27, 223.1–224.20, 225.12–26). Kant recognizes that thisseems strange, to prove a priori a material condition for the possibility of experience, anda material whole at that (cf. e.g., XXI 221.1–18, 222.1–7, 226.1–229.30, 230.7–231.7)! AsEdwards points out (op. cit.), this argument has clear roots in Kant’s refutation of void spacein the Third Analogy (3:182.37, 4:142.25 [A213/B260], cf. Kant’s note at 3:185, 4:145[A218/B265]); as Tuschling points out, such a proof amounts to ascribing a constitutiverole to an idea, which is quite at odds with Kant’s doctrine in the first Critique (“Die Ideedes transzendentalen Idealismus im späten Opus postumum” [op. cit.], p. 110 and note 9).This strongly suggests that Kant deliberately did not distinguish between principles of theunderstanding and of reason when discussing principles that are both regulative andconstitutive.

228. Friedman relies on “the interpretive suggestion” that Kant simply came to see that themathematical approach of the MAdN would not serve to unify all possible moving forcesin space, and that only a unity provided by reflective judgment would suffice (op. cit., 261note 64). This “suggestion” is of itself unconvincing, and it is mitigated by the fact,emphasized by both Tuschling and Förster, but ignored by Friedman, that Kant recognizedin 1798 that the mathematical approach of the MAdN was entirely inadequate, even for itsoriginally intended purposes within the constitutive, constructive domains of physics andthe theory of matter it presupposes.

229. E.g., XXII 59.17–26, 86.10–11; Friedman (op. cit.), 338.

230. Cf., e.g., Friedman (op. cit.), 260–261.

231. I thank Jeff Edwards and Eckart Förster for discussing some of the points of thispaper with me. I gratefully acknowledge that work on this article was supported by anannual research fellowship in 1992 from the National Endowment for the Humanities.