carnap - philosophy and logical syntax

8/3/2019 Carnap - Philosophy and Logical Syntax

1/51

PHILOSOPHYAND LOGICAL SYNTAX

PSYCHE MINIATURESGeneral Series No. 70


2/51

PSYCHE MINIATURES2/6 NetMEDICAL

M,gnJllle F. G. Crookshank. M.D . F.R-L.P,Aphasia S. A. Kinnier Wilson. M.D . F.R,C.P,Rheumatic Diseases M. B. Ray. D.S.O . M.D,Types ot Mind and Body E. Miller.M.B .M.R.C.S.,D.P.MDermatological Neuroses W. J. O'Donovan. O.13.E.M.D,Diagnosis : and Spiritual Heattne F. G. Crookshank. M.D.Medicine: and the Mati Millais Culpin, M.D., F.H.C S.Idiosyncrasies Sir Humphry Rolleston, Bart .G.C. V.O.J( .C.ii.The Constituttonal Factor Arthur F. Hurst. M.D .. F.R.C.P.The Troubled Conscience Professor C. Blonde]Mirror- Writing Macdonald Critchley. M.D . F.R.C. P.Hypochondria R. D. Gillespie. M.D., M.R.C.P .. DP.MIndividual Diagnosis F. G. Crookshank. M.D . F.R.C,PIndividual Sexual Problems F. G. Crookshank. M,D ..F.R.C.P.GENERALSCience and Poetry 1. A. RichardsOver-Population P. Sargant FlorenceMan Not A Machine Eugenio RignanoThe Hunter in Our Midst R. Lowe ThompsonFee. Fi. Fa. Fum H. J. MassingharnMyth in Primitive Psy chologv B. MalinowskiThe Father in Primitive Psycho[oll:>, B. MalinowskiOn History A. L. RowseEconomics and Human Behaviour P. Sargant FlorenceFatalism or Freedom C, Judson HerrickEmergent Evolution W. Morton WheelerMan A Machine Joseph NeedhamLntelligence Claude A, ClaremontThe Basis of ;".emorv W. R. BousfieldSelene. or Sex and the Moon H. Munro FoxThe Standardization of Error Vilhjalmur StefanssonThe A lcherny of Light and Colour Oliver L. ReiserCulture: A Sym posium Ell iot Smith and othersThe Rattle of Behaviorism Watson and McDoucal lOutl ine of Comparative Psychologv C. J. WardenThe Notation of Movement Margaret MorrisMescal H. Klu verProdigal Sons Montgomery EvansThe Future of the Earth Harold TeffrcvsUplift in Economics P. Sargant FlorenceThe Conquest of T'hought by Invention H. S. HatfieldConstitution and Health Raymond PearlA Philosophy in Outline E. S. BennettGhosts and Spirits in the Ancient World E. J. DingwallThe Structure of Insanitv Trigant BurrowPbvloanalvsis William GaltInterpretation and Analysis J. WisdomInternational Communication Shenton and ethersOpposition C. K. Ogden.Lerem y Bentham. 1832-2031 C. K. OgdenWord Economy L. W. LockhartSv mbolic Distance S. BuchananStatement and Suggestion (in Basic English) A. P, RossiterBasic Rules of Reason (in BaSICEnglish) I.A.RichardsBasic English" C. K. Ogden.. For other books on Basic English, see end Page.OTlPT TC:T-:fk'T"\TN r"~T"Tk'~""T"'''' "OT~T

PHILOSOPHY ANDLOGICAL SYNTAXff .)

I~l~.tBY!I-.\., RUDOLF CARNAPPro/,ssor of PhilosOPhy in the German University of Pragu

: . J

LONDON:KEGAN PAUL. TRENCH, TRUBNER & Co. Ltd.

BROADWAY HOUSE CARTER LANE E.C,1935


3/51

aUlUN YLIOPISTOHlstorian ,qitosJt 6 Y G J

Modes of SpeechIII. SYNTAX AS THE METHOD OF PHILO-

SOPHY1. The Material Mode of Speech.2. Modalities3. Relativity in Regard to Language4. Pseudo-questions5. Epistemology6. Natural Philosophy7. What Physicalism Asserts8. What Physicalism Does not

Assert9, The Unity of Science

LITERATURE

64

CONTENTS

Printed in Great Britain b;vR. I. SEVERS. CAMBRIDGE

PREFACE 7I. THE REJECTION OF METAPHYSICS 9

1. Verifiability 92. Metaphysics 153. Problems of Reality 184. Ethics 225. Metaphysics as Expression 266. Psychology 317. Logical Analysis 35

II. LOGICAL SYNTAX OF LANGUAGE 391. "Formal" Theory 392. Formation Rules 413. Transformation Rules 434. Syntactical Terms 475. L-terms 506. Content 567. Pseudo-Object-Sentences. 588. The Material and the Formal

68687275788284889497100

5


4/51

7

PREFACE.

This book gives the content of threelectures delivered at the University ofLondon in October, 1934. The firstchapter has already been printed inPsyche (1934) ; and the present publicationhas been aided by a grant from the Pub-lication Fund of the University of London,for which I desire to express my thanks.My endeavour in these pages is toexplain the main features of the method

of philosophising which we, the ViennaCircle, use, and, by using try to developfurther. It is the method of the logicalanalysis of science, or more precisely, ofthe syntactical analysis of scientificlanguage. Only the method itself is heredirectly dealt with; our special views,resulting from its use, appear rather inthe form of examples (for instance ourempiricist and anti-metaphysical positionin the first chapter, our physicalistposition in the last).The purpose of the book-as of the

lectures-is to give a first impression of


5/51

our method and of the direction of ourquestions and investigations to thosewho are not yet acquainted with them.Therefore the form of presentation aimsmore at general lucidity that at scientificprecision. Formulations which are moreexact and therefore more suitable as abasis for argument, may be found in mybook Logische Syntax der Sprache. R. C.Prague, November 1934.

8

PHILOSOPHY AND LOGICALSYNTAX

1. THE REJECTION OFMETAPHYSICS1. Verifiability

The problems of philosophy as usuallydealt with are of very different kinds.From the point of view which I am heretaking we may distinguish mainly threekinds of problems and doctrines in tradi-tional philosophy. For the sake of sim-plicity we shall call these parts Meta-physics, Psychology, and Logic. Or, rather,there are not three distinct regions, butthree sorts of components which in mosttheses and questions are combined: ametaphysical, a psychological, and alogical component.The considerations that follow belong tothe third region: we are here carrying outLogical A nalysis. T~~function of logicalanalysis is to analyse __:"UJ~l!:9w.I~dge,allassertions of science and ~!"~_ye:ydaylife,in order to make clear the sense of eachs u c h assertion and the connections between

9


6/51

10 11

question is about a proposition whichasserts something about a present per-ception, e.g. " Now I see a red square ona blue ground," then the proposition canbe tested directly by my present per-ception. If at present I do see a redsquare on a blue ground, the propositionis directly verified by this seeing; if Ido not see that, it is disproved. To besure, there are still some serious problemsin connection with direct verification. vVe

will however not touch on them here, butgive our attention to the question ofind_irect verifi~atioI}, which is more impor-tant for our purposes..A proposition pwhich is not directly verifiable can onlybe verified by direct verification of propo-~itions deduced from P together with other~lready verified propositions.Let us take the proposition PI: "This key

is made of iron." There are many ways ofverifying this proposition; e .g . : I place thekey near a magnet; then I perceive thatthe key is attracted. Here the deductionis made in this way:Premises: PI: "This key is made of

iron; " the proposition tobe examined.

P 2 : II Ifan iron thing is placednear a magnet, it isattracted;" this is aphysical law, alreadyverified.

Pa: "This object-a bar-is amagnet;" propositionalready verified.

p4 : HThe key is placed nearthe bar ;" this is nowdirectly verified by ourobservation.

them. One of the principal tasks of thelogical analysis of a given proposition isto find out the jnethod of verification for--.- . . . . . . . _ --.-.that proposition. The question is': Whatreasons can there be to assert this propo-sition; or: How can we become certainas to its truth or falsehood? This questionis called by the philosophers the epistemo-logicalquestion; epistemology or the philo-sophical theory of knowledge is nothingother than a special part of logical analysis,usually combined with some psychologicalquestions concerning the process of know-mg.What, then, is the method of verifi-

cation of a proposition? Here we haveto distinguish between two kinds ofverification: direct and indirect. If the. _ _ _ ,


7/51

From these four premises we can deducethe conclusion :

P6: "The key will now beattracted by the bar."

This proposition is a prediction whichcan be examined by observation. Ifwe look, we either observe the attrac-tion or we do not. In the first casewe have found a positive instance, aninstance of verification of the propo-sition Plunder consideration; in thesecond case we have a negative instance,an instance of disproof of Pj ,In the first case the examination of theproposition PI is not finished. We may

repeat the examination by means of a mag-net, i.e. we may deduce other propositionssimilar to P 6 by the help of the same orsimilar premises as before. After that,or instead of that, we may make anexamination by electrical tests, or bymechanical, chemical, or optical tests, etc.1 in these further investigations allinstances turn out to be positive, thecertainty of the proposition PI graduallygrows. We may soon come to a _.degreeof certainty sufficient for all practical pur-poses, but absolute certainty we can neverattain. The number of instances deducible

from PI by the help of other propositionsalready verified or directly verifiable jsinfinite. Therefore there is always apossibility of finding in the future anegative instance, however small itsprobability may be. Thus the propositionP I can neuer be completely verified. Forthis reason it is called an hypothesis.So far we have considered an individual

proposition concerning one single thing.Ifwe take a general proposition concerningall things or events at whatever time andplace, a so-called natural law, it is stillclearer that the number of examinableinstances is infinite and so the propositionis an hypothesis.Every assertion P in the wide field

of science has this character, that iteither asserts something about presentperceptions or other experiences, andtherefore is verifiable by them, or thatpropositions about future perceptions arededucible from P together with some otheralready verified propositions. Ifa scientistshould venture to make an as~~itio;;--f;~~'~hidi--no 'perceptive propositions ~ould-be.cieduced, what should we say to that?Suppose, e.g., he asserts that there is notonly a gravitational field having an effect

12 13


8/51

14 15

on bodies according to the known lawsof gravitation, but also a levitational field,and on being asked what sort of effect thislevitational field has, according to histheory, he answers that there is noobservable effect; in other words, he con-fesses his inability to give rules accord-ing to which we could deduce perceptivepropositions from his assertion. In thatcase our reply is: your assertion is noassertion at all; it does not speak aboutanything; it is nothing but a series ofempty words; i t is simply without sense.It is true that he may have imagesand even feelings connected with his words.

This fact may be of psychological impor-tance; logically, it is irrevelant. Whatgives theoretical meaning to a propositionis not the attendant images and thoughts,but the possibility of deducing from itperceptive propositions, in other words,the possibility of verification. To givesense to a proposition the presence ofimages is not sufficient; it is not evennecessary. We have no actual image ofthe electro-magnetic field, nor even, Ishould say, of the gravitational field.Nevertheless !h_~propositions which physi-cists assert about these fields have a

perfect sense, because perceptive propo-sitions are deducible from them. I by nomeans object to the proposition justmentioned about a levitational field thatwedo not know how to imagine or conceivesuch a field. My only objection to thatproposition is that we are not told howto verify it.

2. Metaphysics .What we have been doing so far is logical

analysis . Nowweare going to apply theseconsiderations not to propositions ofphysics as before, but to propositions ofmetaphysics . Thus our investigation be-longs to logic , to the third of the threeparts of philosophy spoken about before,but the objects of this investigation belongto the first part.I will call pz,etaphysicat all thosep ropo-

sitions which claim t()represent knowledgeabout something which is overor beyondall experience, e.g. about the real Esse~ceof things, about Things in themselves, theAbsolute, and such like. I do not includeill metaphysics those theories-sometimescalled metaphysical-whose object is toarrange the most general propositions ofthe various regions of scientific knowledge


9/51

in a well-ordered system; such theoriesbelong actually to the field of empiricalscience, not of philosophy, however daringthey may be. The sort of propositionsI wish to denote as metaphysical may mosteasily be made clear by some examples:" The Essence and Principle of the worldis Water," said Thales; HFire," saidHeraclitus; "the Infinite," said Anaxi-mander : "Number," said Pythagoras.HAll things are nothing but shadows ofeternal ideas which themselves are in aspaceless and timeless sphere," is a doc-trine of Plato. From the Monists welearn: (I There is only one principle onwhich all that is, is founded"; but theDualists tell us: "There are two prin-ciples." The Materialists say: f4 All thatis, is in its essence material," but theSpiritualists say: it All that is, is spirit-ual." To metaphysics (in our sense of theword) belong the principal doctrines ofSpinoza, Schelling, Hegel, and-to give atleast one name of the present tinle-Bergson.Now let us examine this kind of propo-

sition from the point of view of verifiability.I t is easy to realise that such propositionsare not verifiable. From the proposition:

\1I

"The Principle of the world is Water JIw . ~ . .~!e_I.1.9J._ble to. deduce any:_propositionasserting any perceptions or feelings orexperiences whatever Whi~h may be ex-pected for the future. Therefore theproposition, (I The Principle of the worldis Water," asserts nothing at all. It isperfectly analogous to the proposition inthe fictive example above about thelevitational field and therefore it has nomore sense than that proposition. TheWater-Metaphysician-as we may callhim-has no doubt many images COIl-nected with his doctrine; but they cannotgive sense to the proposition, any morethan they could in the case of the levi-tational field. _Metaphysicians cannotavoid making their propositions nOI1-verifiable, because if they made themverifiable, the decision about the truthor falsehood of their doctrines woulddepend upon experience and thereforebelong to the region of empirical science.This consequence they wish to avoid,because they pretend to teach knowledgewhich is of a higher level than that ofempirical science. Thus they are com-pelled to cut all connection between theirpropositions and experience; and precisely

16 17n~" "~, YJ 'npl~Tn


10/51

by this procedure they deprive them ofany sense. only his own mind or consciousness is real.Have these .assertions sense?

Perhaps it may be said that assertionsabout the reality or unreality of somethingoccur also in empirical science, where theyare examined inan empirical way, and thattherefore they have sense. This is quitetrue. But we have to distinguish betweentwo concepts of reality, one occurring inempirical propositions and the otheroccurring in the philosophical propositionsjust mentioned. When a zoologist assertsthe reality of kangaroos, his assertionmeans that there are things of a certainsort which can be found and perceived atcertain times and places; in other wordsthat there are objects of a certain sortwhich are elements of the space-time-system of the physical world. This asser-tion is of course verifiable; by empiricalinvestigation every zoologist arrives ata positive verification, independent ofwhether he is a Realist or an Idealist.Between the Realist and the Idealist thereis full agreement as to the question of thereality of things of such and such sort,i.e. of the possibility of locating elementsof such and such sort in the system of thephysical world. The disagreement begins

19

3. Problems of Reality.So far I have considered only examples

of such propositions as are usually calledmetaphysical. The judgment I havepassed on these propositions, namely, thatthey have no empirical sense, may perhapsappear not very astonishing, and eventrivial. But it is to be feared that thereader will experience somewhat moredifficulty in agreement when I nowproceedto apply that judgment also to philo-sophical doctrines of the type which isusually called epistemological. I preferto call them also metaphysical because oftheir similarity, in the point under con-sideration, to the propositions usually socalled. What I have in mind are thedoctrines of Realism, Idealism, Solipsism,Positivism and the like, taken in theirtraditional form as asserting or denyingthe Reality of something. The Realistasserts the Reality of the external world,the Idealist denies it. The Realist-usually at least-asserts also the Realityof other minds, the Solipsist-an especiallyradical Idealist-denies it, and asserts that

18


11/51

of the Reality of the physical world; butwe do not reject it as false, but as havingno sense, and its Idealistic anti-thesis issubject to exactly the same rejection. Weneither assert nor deny these theses, wereject the whole question.All the considerations which apply tothe question of the Reality of the physical

world apply also to the other philosophicalquestions of Reality, e.g. the Reality ofQ J _ l ) , e . r minds, the Reality of the _giv.en,theReality of universals, the Reality ofqualities, the" Reality of ,relations, theReality of numbers, etc. If any philo-sophical _t~~s~s_an?we~ing any of thesequestions positively or negatively is addedto the system of scientific hypotheses,this system will not in the least become.more effective; we shall not be able to~ake any further prediction as to futureexperiences. Thus all these philosophicaltheses are deprived of empirical content,oftheoretical sense; they are pseudo-theses.If I am right in this assertion, thephilosophical problems of Reality-as dis-tinguished from the empirical problems ofreality-have the same logical characteras the problems (or rather, pseudo-problems) of transcendental metaphysics

21

I '

only when the question about the Reality


12/51

earlier referred to. For this reason I callthose problems of Reality not epistemo-logical problems-as they usually arecalled-but metaphysical.Among the metaphysical doctrines that

have no theoretical sense I have alsomentioned Positivism, although the ViennaCircle is sometimes designated as Positiv-istic. It is doubtful whether this desig-nation is quite suitable for us. In anycase w~_g9__19~assert the thesis that onlythe Given is Real, which is one of' the--'-~-~ -- . '. . ' _ " -principal theses of traditional Positivism.The name Logical Positivism seems moresuitable, but this also can be misunder-stood. At any rate it is important torealize that our doctrine is a logical oneand has nothing to do with metaphysicaltheses of the Reality or Unreality ofanything whatever. What the characterof a logical thesis is, will be made clearIn the following chapters.

I,

or Ethics. The word it Ethics 11 is usedin two different senses. Sometimes acertain empirical investigation is calledtI Ethics," viz. E_~Y~Q2JggiGpJ_~Ildocio-logical investigations about the actions ofhuman beings, especially regarding theorigin of these actions from feelings andvolitions and their effects upon otherpeople. Ethics in this sense is an empirical,scientific investigation; it belongs toempirical science rather than to philo-sophy. Fundamentally different from thisis ethics in the second sense, as thephilosophy ofmoral values or moral norms,which one can designate normative ethics.This is not an investigation of facts, buta pretended investigation of what is goodand what is evil;"what it is right to do andwhat it is wrong to do. Thus the purposeo-fthis philosophical, or normative, ethicsis to state norms for human action orjudgments about moral values.It is easy to see that it is merely adifference of formulation, whether we state

a norm or a value judgment. A normor rule has an imperative form, forinstance: "Do not kill!" The corres-ponding value judgment would be: "Kill-ing is evil." This difference of formulation

'IIilPI !I,II!,'I,II

4. Ethics.One division of philosophy, which by

some philosophers is considered the mostimportant, has not been mentioned atall so far, namely, the philosophy ofvalues,with its main branch, moral philosophy

22

1 ,~

23


13/51

has become practically very important,especially for the development of philo-sophical thinking. The rule, UDo notkill," has grammatically the imperativeform and will therefore not be regardedas an assertion. But the value statement,I( Killing is evil," although, like the rule,it is merely an expression of a certainwish, has the grammatical form of anassertive proposition. Most philosophershave been deceived by this form intothinking that a value statement is reallyan assertive proposition, and must beeither true or false. Therefore they givereasons for their own value statementsand try to disprove those of their oppon-ents. But actually .(l value statement isnothing else than a command in a mis-leading grammatical form. It may haveeffects upon the actions of men, and theseeffects may either be in accordance withour wishes or not; but it is neither truenor false. It does not assert anything andcan neither be proved nor disproved.This is revealed as soon as we apply to

such statements our method of logicalanalysis. rg!Il. t~~ st~t~~~_I?:!'~J~JIUn.g.is evil" we cannot deduce any proposition

24

about future experiences. Thus this state-ment is not verifiable and has no theoreticalsense, and the same thing is true of allother value statements.Perhaps somebody will contend in oppo-

sition that the following proposition is de-deducible: It Ifaperson kills anybody hewillhave feelings ofremorse." But this proposi-tion is in no way deducible from the propo-sition It Killing isevil." Its deducible onlyfrom psychological propositions about thecharacter and the emotional reactions ofthe person. These propositions are indeedverifiable and not without sense. Theybelong to psychology, not to philosophy;to psychological ethics (if one wishes touse this word), not to philosophical ornormative ethics. The propositions ofnormative ethics, whether they have theform of rules or the form of value state-ments, have no theoretical sense, are notscientific propositions (taking the wordscientific to mean any assertive propo-sition).To avoid misunderstanding it must

be said that we do not at all denythe possibility and importance of a scien-tific investigation of value statements aswell as of acts of valuation. Both of these

25


14/51

26 27

I

I)1

I'It

Ii

of scientific propositions. But when I saythat they are without _sense, assent willprobably seem more difficult. Someonemay object: these propositions in themetaphysical books obviously have anI> _ o _ _ . . . . . . . . _ ~ _~ : f ~ ~ ! . _ l _ : 1p _ ~ _ ~ _ .t.h~reader, and sometimes avery strong effect; therefore they cer-tainly express something. That is quitetrue, ~y-_~q_~)Cpres.~omething, but never-theless they have no sense, no theoreticalcontent.We have here to distinguish two

~.~!!~!_io.I1sofanguage, which we may call! p . ~ _~~pr.~ssive function and _.the repre,-sentative function. Almost all the con-

are acts of individuals and are, like allother kinds of acts, possible objects ofempirical investigation. Historians, psy-chologists, and sociologists may giveanalyses and causal explanations of them,.and such historical and psychologicalpropositions about acts of valuation andabout value statements are indeed mean-ingful scientific propositions which belongto ethics in the first sense of this word.But the value statements themselves arehere only objects of investigation; theyare not propositions in these theories, andhave, here as elsewhere, no theoreticalsense. Therefore we assign them to therealm of metaphysics. -- .scious and unconscious movements of aperson, including his linguistic utterances,

express something of his feelings, hispresent mood, his temporary or permanentdispositions to reaction, and the like.Therefore we may take almost all hismovements and words as symptoms fromwhich we can infer something about hisfeelings or his character. That is theexpressive function of movements andwords. But besides that, a certain portionof linguistic utterances (e.g. Hthis book isblack "), as distinguished from other lin-guistic utterances and movements, has a

5. Metaphysics as Expression.Now we have analysed the propositions

of metaphysics in a wide sense of thisword, including not only transcendentalmetaphysics, but also the problems ofphilosophical Reality and lastly normativeethics. Perhaps many will agree that thepropositions of all these kinds of meta-physics are not verifiable, i.e. that theirtruth cannot be examined by experience.And perhaps many will even grant thatfor this reason they have not the character


15/51

9nly.~ eX.R~s~y~_J~g~t!().n, no repre-sentative function. Examples of thisare cries like HOh, Oh " or, on a higherlevel, lyrical verses. The aim of a lyricalpoem in which occur thewords "sun-shine" and It clouds," is not to inform usof certain meteorological facts, but toexpress certain feelings of the poet andto excite similar feelings in us. A lyricalpoem has no assertional sense, no theoreti-cal sense, it does not contain knowledge.The meaning of our anti-metaphysical

thesis may now be more clearly explained.This thesis asserts that metaphysicalpropositions -.. like lyrical verses-s-haveonly an expressive function, but no repre-~.~r:t.~.~tiy~u~ction. Metaphysical propo-sitions are neither true nor false because-. . ..,they assert I}Q.th~pg,they contain neitherknowledge nor error, they lie completelyoutside the field of knowledge, of theory,Qllt.j9


16/51

system may be an expression of theemotional state of someone who takes lifeas an eternal struggle; an ethical systemof Rigorism may be expressive of a strongsense of duty or perhaps of a desire torule severely. Realism is often a symptomof the type of constitution called bypsychologists extraverted, which is charac-terized by easily forming connections withmen and things; Idealism, of an oppositeconstitution, the so-called introverted type,which has a tendency to withdraw fromthe unfriendly world and to live withinits own thoughts and fancies.Thus we find a great similarity between

metaphysics and lyrics. But there is onedecisive difference between them. Bothhave no representative function, no theor-etical content. Ametaphysical proposition,however-as distinguished from a lyricalverse-fjcems to have some, and by thisnot only is the reader deceived, but themetaphysician himself. ,!!~.elieves thatin his metaphysical treatise he has assertedsomething, andis led_~y_t~~_~ntoargumentand polemics against the propositions of,some other metaphysician. A poet, how-~ver,"does--iiot assert that the verses ofanother are wrong or erroneous; he

usually contents himself with calling thembad.The non-theoretical character of meta-

physics would not be in itself a defect. ,all arts have this nOll-theoretical characterwithout thereby losing their high valuefor personal as well as for social life. Thedanger lies in the d t } _ c : . . ~ P _ t j 1 ! _ _ ~b_g_rg~I~! ofI E . e . ! ? : p p y~!_~-~_; i J _ . - g J Y . . ~ ~ _ J h ~ _ , j 1 l . ! : ! ig I ? :_ _ of~~QwJedg~.,~g~,?~_~_~ t~ ~ J lY g !Y ! ! l _ g any!fE_


17/51

--eQ). . . .~0I : : l~Z0 ~. .HU :;lZ Q)P r: 4 ~0~ o ~f ; I ; l p ~i: : t!) '+-4E j 0af ; I ; l fx 4 .BIII 0 e nf ; I ; l ~~ CI lIl.f ; I ; l Q)p : : : il

"-)odQ). . . . .oCI lz0. . .H fI iz ep . A \.Q~ P o t II.--. Ie n -6 " 0. . .e n>. .Q.Q 0P o t '5. a '-l~ .~Q)

A ! ~: ; s- - ~. t'i ~-I

32

by their help we can verify the psycho-logical propositions. !3..~the P!_QP .Q~ i J j9n~of psychology , l ? ~ ~ c ? l 1 g _ . .!g .!h~..egion .~fempirical sciencein justthe s~~ ..~~y~ .~_~do 'the propositions of chemistry, ..biology,history .and the" like. The character ofpsychology is by no means more philo-sophical than that of the other sciencesmentioned. When we look at the his-torical development of the sciences we seethat philosophy has been the mother ofthem all. One science after another hasbeen detached from philosophy and hasbecome an independent science. Onlyin our time has the umbilical cord betweenpsychology and philosophy been cut.Many philosophers have not yet realizedquite clearly that psychology is no longeran embryo, but an independent organism,and that psychological questions have tobe left to empirical research.Of course we have no objection toconnecting psychological and logical in-vestigations, any more than to connect-ing investigations of any scientific kind.We reject only the confusion of thetwo kinds of questions. We demandthat they should be clearly distinguished

33

'\I It!.i":i


18/51

even where in practice they are com-bined. The confusion sometimes con-sists in dealing with a logical quest jon C lSif it were a psychological one. This mis-take=-called Psychologism-Ieads to theopinion that logic is a science concerningthinking, that is, either concerning theactual operation of thinking or the rulesaccording to which thinking should pro-ceed. But as a matter of fact the in-vestigation of operations of thinking asthey really occur is a task for psychologyand has nothing to do with logic. Andlearning how to think aright is what wedo in every other science as well as inlogic. In astronomy we learn how tothink aright about stars; in logic welearn how to think aright about the specialobjects of logic. What these specialobjects of logic are, will be seen in thenext chapter. In any case ~Jnkigg is~ ..~!!._~ject oflogic, but __~.psychology.Psychological questions concern allkinds

of so-called psychic or mental events, allkinds of sensations, feelings, thoughts,images, etc., whether they are consciousor unconscious. These questions of psy-chology can be answered only by experi-ence, not by philosophising.

34

7. Logical Analysis.The only proper task of Philosophy is

Logical Analysis. And now the principalquestion to be answered here will be:cr What is logical analysis?" In our con-siderations so far we have already prac-tised logical analysis: we have tried todetermine the character of physical hypo-theses, of metaphysical propositions (orrather, pseudo-propositions), of psycho-logical propositions. And now we haveto apply logical analysis to logical analysisitself; we have to determine the characterof the propositions of logic, of thosepropositions which are the results oflogical analysis.The opinion that metaphysical propo-

sitions have no sense because they do notconcern any facts, has already been ex-pressed by Hume. He writes in the lastchapter of his "Enquiry ConcerningHuman Understanding" (published in theyear 1748) as follows: "It seems to me,that the only objects of the abstractsciences or of demonstration, are quantityand number. . . . All other enquiries ofmen regard only matter of fact and exist-ence; and these are evidently incapableofdemonstration. When we run over

35


19/51

libraries, persuaded of these principles,what havoc must we make? If we takein our hand any volume, of divinity orschool metaphysics, for instance; let usask, Does it contain any abstract reasoningconcerning quantity or number? No.Does it contain any experimental reasoningconcerning matter of fact and existence?No. Commit it then to the flames: forit can contain nothing but sophistry andillusion." We agree with this view ofHume, which says-translated into ourterminology-that only the propositions ofmathematics and empirical science havesense, and that all other propositions arewithout sense.But now it may perhaps be objected:

HHow about your o~ ...propositions?In consequence of your VIew yourown writings, including this book, wouldbe without sense, for they are neithermathematical nor empirical, that is,verifiable by experience." What answercan be given to this objection? Whatis the character of my propositions andin general of the propositions of logicalanalysis? This question is decisive forthe consistency of the view which hasbeen explained here.

36

An answer to the objection is givenby Wittgenstein in his book TractatusLogico-Philosophicus. This author hasdeveloped most radically the view thatthe propositions of metaphysics are shownby logicalanalysis to bewithout sense. Howdoes he reply to the criticism that in thatcase his own:propositions are also withoutsense? He replies by agreeing with it. Hewrites: H14e .result of philosophy is not anumber of Iphilosophical propositions I' but.!omake proposition? clear" (p. 77). HMypropositions are elucidatory in this way: hewhounderstands me finally recognizes themas senseless, when he has climbed outthrough them, on them, over them. (Hemust so to speak throwaway the ladder,after he has climbed up on it.) He mustsurmount these propositions; then hesees the world rightly. Whereof one can-not speak, thereof one must be silent."(p. 189).I, as well as my friends in the Vienna

Circle, owe much to Wittgenstein, especi-ally as to the analysis of metaphysics.But on the point just mentioned I can-not agree with him. In the first placehe seems to me to be inconsistent in

37


20/51

what he does. He tells us that one can-not state philosophical propositions andthat whereof one cannot speak, thereofone must be silent; and then instead ofkeeping silent, he writes a whole philo-sophical book. Secondly, I do not agreewith his statement that all his propositionsare quite as much without sense as meta-physical propositions are. My opinion isthat ~ ...Rn:~at.J).~rn1:>er:.o f his propositions(unfortunately not all of them) .have infact sense; and that !p.~ same is true forall propositions of logical. analysis.I t will be the purpose of the followingchapters to give reasons for this positive

answer to the question about the characterof philosophical propositions, to show away of formulating the results of logicalanalysis, a way not exposed to the objec-tion mentioned, and thus to exhibit anexact method of philosophy.

II. LOGICAL SYNTAX OFLANGUAGE

38

1. HFormal" TheoryIn this chapter an explanation will be

given of a theory which we will call LogicalSyntax, and it will be shown how tooperate with the syntactical method.Although the word" philosophy" will nothere occur, the syntactical method, as weshall try to make clear in the last chapter,brings us to the very basis of philosophy.The logical syntax of a certain language

is to be understood as the i O ! ! ! ! q , _ L theory2L__h~l_.J_~p.~.~ge... This needs furtherexplanation. We will call Hormal" suchconsiderations or assertions concerning alinguistic expression as are without anyreference to sense or meaning. A_.f


21/51

If I assert that this expression consistingof four words is a sentence, and further,that the first word is an article, the seconda substantive, the third a verb, and thefourth an adjective, all these assertionsare formal assertions. If, however, Iassert that that sentence concerns a book,or that its last word designates a colour,then my assertions are no t f orma l, becausethey have to do with the meaning of thewords. A formal investigation of a lan-guage would appear to have very narrowlimits. Actually, however, this is not thecase, because, as we shall see later, manyquestions and considerations which are~.xp~sed-lft-a-ri.on-forriialway can beformulated in the formal mode.Such a formal theory of language is, so

far as mathematics is concerned, alreadyknown by the work of Hilbert. Hilberthas propounded a theory, which he callsmetamathematics or theory of proof, andin which the formal method is applied.In this theory of Hilbert, mathematics isdealt with as a system of certain symbolsto be operated according to certain rules,and the meaning of the symbols is nowherespoken of, but only the various kinds ofsymbols and the formal operations to

40

which they are subjected. Now mathe-matics is a special part of the whole oflanguage, which includes many other andquite different branches. And the sameformal method which Hilbert has appliedin his metamathematics to the system ofmathematics, we apply in our logicalsyntax to the whole language-system ofscience, or to any special part of it, or toany other language-system whatsoever.

2. F orm ation R ules.When we say that the objects of logical

syntax are languages, the word II Ian-gyage " is to be understood as the ~yste1111p i tlJe rules of speaking, as distinguishedfrom the acts of speaking. Such .~.Ian-guage-system .._.~QA?!~~Sf two kinds ofrules, which we will' ~~l(i~r~ation rulesand transformation rules. The formation

" '.. ._.' . . . . . . ".rules of a certain language-system 5,determine how ~'!1te11:ce$of the system 5can be constructed out of the different... ~. -. - .kinds. of symbols. One of the formationrules of the English language, for instance,determines that a series of four words ,first an article, second a SUbstantive, thirda verb of a certain class, and fourth anadjective, constitutes a sentence. Such a

41


22/51

formation rule is obviously similar togt:_"iticaT~es: especially to the ~esofgra.iliffiatlcai syntax. But the usualrules ofgrammatical syntax are not alwaysstrictly formal; for instance, we may citethat rule of Latin grammar which deter-mines that substantives designatingwomen, countries, towns, or trees are offeminine gender. Such references to themeaning of the words are excluded inlogical syntax as distinguished from gram-matical syntax.The to~~_!y'_ ? f _theformationrules of..a

~~@.~~-=~yst~m 5 is the ...s~~a~ . _ . ! l l ~definition of the term If sentence of 5."This definition can be stated in the fol-lowing form: "A series of words is then,and only then, a sentence of the system5, if it has either this, that, or the otherform." Now for a natural language, suchasEnglish, the formation rules can scarcelybe given completely; they are too com-plicated. The logicians, as we know, havemade language-systems--or at least frame-works for such-which are much simplerand also much more exact than thenatural languages. Instead of words, theyuse symbols similar to the mathematicalsymbols. Take, for example, the most

42

developed of these symbolic languages,that constructed by Whitehead and Russellin their workPrincipia M athematica. Twoof the principal formation rules of thislanguage are as follows: (1) an expressionconsisting of a predicate (that is, one ofthe small Greek letters ' 4 > ' , 'l/", etc.) andone or more individual variables (the smallRoman letters' x ', 'v'. etc.) is a sentence;(2) an expression consisting of two sen-tences and one connecting sign C v " ':',' : : : > ' , '=)between them isalsoa sentence.

andIf all a are b ""all bare c II

3. Transformation Rules.Much more important than the for-

mation rules are the transformation rules.. . . . . ~..They .4~termine.how given sentences may~e transformed into others; in other~ords: how from given sentences we may~1t!~rothers. Thus in the English languagethere is the rule, that from the twosentences:

we may infer: "all a are c."Here only the framework of the sen-

tences is given, not the sentences them-selves. In order to make sentences we

43


23/51

have to substitute three English sub-stantives in the plural form for the threeletters' a,' "b,' 'c.' To give an illustration,from the two sentences:

" all eagles are birds "and " all birds are beasts "we may infer: "all eagles are beasts."In the symbolic language of Whitehead

and Russell we have the following rule :from two sentences of the form(fA"

It is to be noted that ~!l.~~io~..O_FIj~i-ti~~___~!lt~g_~.~_.Qf_~._.la!?-_g~:g~an also bestated in .t_heform of a rule .~{inference,and therefore also' I n the form ofa partof the definition of " direct consequence."The difference is only that in this casethe class of premises is the null class (i.e.the class which has no members). Thusinstead of ruling: " , p:::>.pvq , is to be aprimitive sentence of the language S ", wemay say: '" p:::>.pvqr is to be a directconsequence of the null class of premises."If a class P of premises is connectedwith a certain sentence C by a chainof sentences in such a way that everysentence of this chain is a direct con-sequence of some sentences preceding inthe chain, we call the sentence C aconsequence of the class P of premises.This term" consequence" is, as we shallsoon see, one of the most important termsof logical syntax.We have seen that _.~_}~nguage-system

is a system of rules of formationandi~~risf?~i!-i~!J~!i--'-A~cording-tohis theL9g~~~".~~t~ ..of ,a..language-system. S~.o~sists of two parts : the investigationor analysis of the formation rules of S, and.. .,.... . . .that of the transformation rules of S.The .., _

and " A::::>B,where ::::>is theimplication-sign

we may infer: "B".The .totality of t_!1e~~?fo~1J.laion .rules

of a language-system Smay be formulatedas the definition of the te~m ."--di;~~t.. '~"~ .y ~consequence in S:," Thus the transfor-mation rules of the Principia Mathematicamay be stated as follows: II In the systemPM a sentence is to be called a directconsequence of a class of other sentences--called premises-then and only then, ifone of the following conditions is fulfilled:

(1) the sentence has the form' B ' andthe class of premises consists of ' A ' andA:::>B J(2) ;

(3 ) "44 45


24/51

first part is, as observed above, somewhatsimilar to grammar, the second part, tologic, especially to the logic of inferenceor deduction. _ r t is generally supposedthat grammar and logic have quite differentcharacters, grammar being concerned withl_i:lguistic expressions, and logic with th~meaning of thoughts or of propositions.But in opposition to this the developmentof modern logic_~~~~_h~~nmore and moreclearly that the rules of --l!i!erence---canheexpressed in a purely formal manner, -thatI S ; '~itliout any reference to meaning.Our task is.merely to-maw theconsequencefrom this development and to constructthe whole system of logic in a strictlyformal way. We shall then have to doneither with thoughts as mental acts norwith their contents, but only with sen-tences, and with sentences not as vehiclesof meaning or sense, but only as seriesof symbols, of written, spoken, 'or othersigns. It will now be clear why we donot employ here the usual word "propo-sition." Sometimes it means, not a sen-tence, but what is expressed by a sentence,and very often it is used ambiguously.Therefore we prefer to use the wordII sentence."

Between logic and grammar, or in otherwords, between the transformation rulesand the formation rules, there is no fund a -mental difference. Transformation or..--- --'-inference i~en~~only'_ ~ 1 2 _ ? ~ . ._ t E . ~ _ _~ ? f 1 1 1 ~ 1character ~,~.h_e_.,?_~~t~,n~es!only upon theirsyntactical form. That is the reason whywe apply the name II syntax n not, as isusually done in linguistics, to the formationrules alone, but to the system containingboth kinds of rules together.

4. Syntactical Terms.I~____j~rms_:_,'_~ep1~J!~~_~_~__nd __.~_direc t

s:


25/51

Hfalse" in syntax, because whether agiven sentence is true or false will generallydepend not only upon the syntactical fonnof the sentence, but also upon experience;that is to say, upon something extra-linguistic. It may be however that .incertain cases a sentence is true or falseonly by reason of the rules of the language.Such sentences we will call valid andcontraualid respectively.Our definition of validity is as follows:

a sentence is called valid, if it is a conse.-_quence of the null class of premises.Thus in the language of Russell the sen-tence ' pv ,....., ,-usually called the Principleof the Excluded Middle-is a valid sen-tence; and so likewise are all othersentences for which proofs are given inthe Principia Mathematica. A proof inthis work is a series of sentences of suchkind that each sentence of the series iseither a primitive sentence or inferredfrom preceding sentences of the series.Now a primitive sentence is a direct con-sequence of the null class of premises.Therefore a proof in the Principia M aihe-matica is a chain of direct consequencesbeginning with the null class of premisesand ending with the sentence proved.

This proved sentence is thus a consequenceof the null class and therefore-accordingto our definition-valid.Turning to the term "


26/51

constants. Suppose, for instance, 'a' andf b' to be names of persons, t S ' to desig-nate the relation of sonship, then I aSb '(in words: Ha is a son of b ") is an jnde-terminate sentence, because its truth canobviously not be determined by the rules-..of the system of Russell.5. I-Terms.In the symbolic languages of modem

logic the transformation rules, to which,as has been pointed out above, theprimitive sentences also belong, are usuallychosen in such a way that they seem to beright for logical or mathematical reasons.But it would likewise be possible to statea language-system which, besides suchlogical rules, also contained extra-logicalones. Take for instance the system ofPrincipia Mathematica. In its presentform it contains only such primitivesentences and rules of inference as havea purely logical character. Transformationrules of this logical or mathematicalcharacter we will call Lsrules. Now wecould add to the system of PrincipiaM athema ti ca transformation rules of anextra-logical character, for instance somephysical laws as primitive sentences,

50

as, for example, Newton's principles ofmechanics, Maxwell's equations of electro-magnetics, the two principles of thermo-dynamics, and such like. In order tohave a comprehensive name for the ~tra-logical transf~~!io!!~.!,~.~~._ we will callthem phy~ic~ rules or !._~~~!!..~~Thus a transformation rule of a languageis either an L-rule or a P-rule. The distinc-tion of these two kinds of rules is very im-portant. We have only given some roughindications of it, but it is possible to definethis distinction in an exact and strictlyformal way, that is, without any referenceto the sense of the sentences. Omittingthis exact definition for the sake ofbrevity,however, let us simply suppose that thereis given a certain language-system, forinstance the system of Principia Mathe-matica with the addition of some physicallaws as primitive sentences, in which thegiven transformation rules are alreadydivided into L-rules and P-rules.We have called a sentence C a con-

sequence of a class P of sentences-thepremises-if there is a chain of sentencesconstructed according to the transfor-mation rules connecting the class P withthe sentence C. Suppose now that in

51


27/51

a certain case only L-rules are applied;then we call C an L-consequence of P.If on the other hand C can be deducedfrom P only by applying also P-rules,in other words if C is a consequence, butnot an L-consequence, of P, we call Ca .f-consequence of P. Let us take forexample the following class P of twopremises:

PI: The body A has a massof 3 grammes.Pz: The body B has a massof 6 grammes.Then we can deduce from P the

As we have defined corresponding tothe tenn " consequence 11 an L-tenn anda P-term, we may in an analogous waydefine corresponding L-tenns and P-tennsfor the other general terms already defined.Thus we will call a sentence which is true.~yreaso.nof the L~i-ilJ.esalo~~,L-valid ~ranalytic. The exact definition of thist~~ is perfectly analogous to the defi-nition of "valid": a sentence is calledanalytic if it is an L-consequence of t~enull class of premises. Similarly we WIllcall a sentence which is false by reasonof the'-L~rUie~alone,L-contravalid or _ ~ : ? 1 ! -tradictoY),.. ,The formal definition is asf ~ l i o w s - : a sentence is called contradictoryif every sentence of the language is anL-consequence of the same. A sentenceis called L-determinate if it iseither analyticor contradictory. ""rfforthe determinationofthe truth or falsehood of a given sen-tence the L-rules do not suffice, in otherwords if the sentence is not ~-:-9~teI1I:li!l:.te,it is ~~li~dL-i~deter~i;ate or.sYl1thr:tir.The synthetic sentences are those whichassert states of affairs. The terms" ana-lytic" and "synthetic" have alreadybeen used in traditional philosophy; theyare especially important in the philosophy

53

following two consequences among others :C1: The mass of B is double

the mass of A.C2: If the same force is acting

on A and onB, the acceler-ation of A will be doublethat of B.

For the deduction of C1we need onlyL-rules, that is rules of logic and arith-metic, while for the deduction of C2besides these we need P-rules, namely thelaws of mechanics. Therefore C1is anL-consequence, but C2, a P-consequence,of the class P of premises.

52


28/51

of Kant; but up till now they have notbeen exactly defined.In a language-system which contains

only L-rules, for instance in the systemof Principia M aihematica, each of thedefined general terms agrees completelywith the correspondipg L-term. Thusevery valid sentence (forinstance (pv '" p')is analytic, every contravalid sentence (forinstance' p. '" p') is contradictory; inde-terminate sentences, and only. these (forinstance (aSb,' Ii a is a son of b "), aresynthetic.

contentequipollentsynonymous

If a sentence is valid, but not analytic,we call it P-valid. If a sentence is contra-valid, but not contradictory, we call itP-contravalid. The other P-terms are notso important.

Generalterms

consequencevalidcontravaliddeterminateindeterminate

The terms just defined give a classifi-cation of sentences which we may repre-sent by the following scheme :

valid indeterminate contravalid,~. . . . . " ,I C r II '-y-'P-valid I.: ~P-contravalidcontradictory

L-terms P-terms

analytic syntheticThe totality of the sentences of the

language is comprehended in the abovediagram. Some of the sentences are eithervalid or contravalid, according to thetransformation rules ingeneral; the othersare indeterminate. Among the valid sen-tences some are analytic, namely thosewhich are valid on the basis of the L-rulesalone; the others are P-valid. In thesame way some of the contravalid sen-tences are contradictory, the others P-contravalid. The sentences which areneither analytic nor contradictory aresynthetic. The three L-terms, namelyII analytic," ((synthetic II and (I con:ra-dictory," are very often used in the logicalanalysis of any scientific theory. Lateron we shall consider some examples.

L-consequence(L-valid) analyt ic(L-contravalid)

cont t 'adict01 'YL-determinate(L-indeterminate)

synthet ic

P-consequenceP-validP-contravalid

5455


29/51

of f o rmal investigation, namely by thehelp of the formal, syntactical termHsentence" defined by the formationrules of the language. Secondly it maybe asked what sense a given sentence has.This question can be answered by the helpof the formal, syntactical term Hcontent"as just defined.The content of a sentence represel1ts_.... . .--... .. _ --._-".. II "its sense, so far as the word senseI s intended to designate something ofa purely logical character. Sometimesby Hsense" is meant the kind of thoug~tsand images that are connected withthe given sentence. But in this casethe question is a psychological one andhas to be examined by the experimentalmethod of psychology. In logical analysiswe are not concerned with such questions.All questions of sensell:a~~g ( ; L ? ~ch~.allylogical character can be dealt with by theformal method of syntax.. Sometimes two e1!.t~~~_~~f quite unlikewording nevertheless have the ~e sense,as asserting the same state. We will callsuch sentences ~qy: i j_Q~l~n~. The formaldefinition is obvious: jwo sentencesar~called equi1?o~~p.!f t.~~y_hav.e" t h ~ . _ s~lTle.content, in other words if they are

57

6. Content.If we wish to characterize the purport

of a given sentence, its contents, itsassertive p~wer, so to speak, we have toregard the class of those sentences whichare consequences of the given sentence.Among these consequences we may leaveaside the valid sentences, because theyare consequences of every sentence. Wedefine therefore as follows: the class ofthe non-valid consequences "~f a givensentence is called the content of this sen-tence.The method which we are using hereand which we call tqgical syntax is charac-

terized by limiting itself to terms definedin a strictly formal way. One might per-haps be inclined to think that it is a defectof this formal method not to be able todeal with questions of sense. But in factthis method is able to do that, at leastin a certain respect. Concerning a givenseries of signs, for instance a series ofwords in a word-language, there are twoquestions of sense. The first is, whetherthat series of words has a sense or not.If here Hsense" means "theoreticalsense," II assertive sense," then such aquestion can be answered within the range

56

\1\iffiLii!


30/51

consequences of each other. Similarly JWoexpressions which are not themselvessentences, but occur in sentences, mayhave the sa,~e sense, the same meaning,in spite of a quite different wording.This relation, which we will designate bythe term Hsynonymous, ncan also be definedin a formal manner: two expressions arecalled mutually synonymous, if the con-.t~nt of any sentence containing" one o fthem. is not changed if we replace 'thatexpression by the other. Thus, for instance,the expressions (5 + 2' and (4 + 3'are synonymous, because the content ofa sentence will not be changed if we replacein this sentence ( 5 + 2' by ( 4 + 3' ortnce versa.

instance the following form: "Such andsuch a sentence contained in a certaintheory is synthetic, but a certain othersentence is merely analytic," or: If Thisparticular word of such a theory is synony-mous, but not L-synonymous, with thatand that combination of words," and soon.If sentences of this simple form con-

taining well-defined syntactical terms aregiven, it is easy to see that they aresyntactical sentences. But thereareothersentences which seem to be of quite adifferent kind and nevertheless really. aresyntactical, This fact is very important,especially in dealing with philosophicalsentences. I have already mentionedmy opinion, which will be explained inthe next chapter, that philosophical sen-ienc~~belo!?:g_._! 9 . _ . ._~YE!?- ! ' It must beconfessed that this opinion seems not toagree with obvious facts, for philosophicalsentences-even after the elimination ofmetaphysics-seem to concern not onlythe form of linguistic expressions but also,and perhaps mainly, quite other objects,such as the structure of space and time,the relation between cause and effect, therelation between things and their qualities,

7. Pse'udo-Object-Sentences.The above are some examples of syn-

tactical terms, all based upon the termt. consequence" which is the principalterm of syntax. !l_: !~ -ta.sk__L~Yr.l_~axisto state such definitions as those of thegiven examples and to analyze given sen-tences, proofs, theories, and the like, bythe help of such syntactical terms. Theresults of such an analysis are then for-mulated as syntactical sentences having for

58

II

59


31/51

the difference and the real relationsbetween the physical and the psychical,the character of numbers and numericalfunctions, the necessity, contingency, pos-sibility or impossibility of conditions, andthe like. We shall have to show laterthat philosophical sentences _of such kinds?nly seem by their deceptive appearanceto concern the objects mentioned, butthat they really concern linguistic forms.... ' . '. . . . . . . . . -"'-For the present, however, we shall notenter into the consideration of such philo-sophical sentences, but will try to explainin general under what conditions a sentencehas such a deceptive f6ffi1:-"" """"For this purpose we will distinguishthree kinds of sentences. About syntacticalsentences I have just spoken; they concernthe form of linguistic expressions. Wi ththese are to be contrasted those sentenceswhich concern not linguistic expressionsbut extra-linguistic objects; they maybe called rea l ob jec t- sen tences . There is alsoa third, an intermediate kind of sentence.Sentences of this kind are, so to speak,,~phibious, being like object-sentencesas to their form, but like syntacticalsentences as to their contents. Theymay be called s eu do - o bje ct - s en te nc es .

60.-

o. . . . .

.!:l. . . . . ..oC'l

."0ef/). . . . .

.C I5-61

..o"< t '


32/51

Let us look at the examples tabulated onthe opposite page. (la) UThe rose isred" is a real object-sentence which con-cerns the rose as object. (Ic) " The word, rose' is a thing-word" is a syntacticalsentence; its object is not the thing rosebut the word' rose,' a linguistic expression.Finally (lb) "The rose is a thing" is anexample of a pseudo-object-sentence. Thissentence has the same grammatical subjectas the sentence Ia and thus appears, likeit, to concern the thing, rose, but there isa fundamental difference between the twosentences. The sentence la is synthetic;it really asserts some quality of the rose.But from the sentence Ib we cannot learnany quality of the rose, neither as to itscolour, nor size, nor form, nor anything~lse. This sentence Ibis analytic; wecan ascertain its truth without observingany rose, by only considering to whatsyntactical kind the word I rose' belongs,namely that it is a thing-word. Thus wesee that the sentence 1b asserts the same... __._ ...-_~ _ I

the quality of being a thing. The generaldefinition will be: a syntactical quality Q2is called parallel to the quality Ql if it isthe case that when, and onlywhen, anobjectpossesses the quality Ql does a designationof this object possess the quality Q2' Andthe criterion of a pseudo-object-sentencecan now be stated as follows (if we regardonly sentences of the simplest form) : sucha sentence attributes to an object (say a)a quality Ql to which a parallel syntacticalquality Q2can be found. Such a sentence, Ql(a) , can then be translated into thesyntactical sentence I Q2(' a ')' whichattributes the quality Q2 to a designationof that object.This brings out more clearly the dif-

ference between the sentences la and lb.While to the quality of being a thing thereis a parallel syntactical quality, namelythat of being a thing-designation, to thequality of being red there is no parallelsyntactical qua.lity-. the designations ofred things have no common characteristicsyntactical quality. For instance, fromthe designation ((my pencil" alone weare not able to decide whether it is a desig-nation of a red thing or not; we shouldhave to look at the designated object

as 1c, because always and only when acertain object is a thing is its designatingword a thing-word.We may call the quality ofbeing a thing-

designation a parallel syntactical quality to62 63

, I


33/51

itself, namely my pencil. Therefore thesentence " The rose is red " is not a pseudo-object-sentence, but a real object sentence.

,,.

examples. Take the sentence: HThefirst chapter treats of metaphysics." Thissentence belongs to the material mode;the corresponding sentence of the formalmode is: itThe first chapter contains theword' metaphysics '." To take a morestriking example, suppose we have ageographical book about Africa and wemake the statement: HThis book treatsof Africa." Then this sentence (3b)belongs to the material mode; the corres-ponding sentence of the formal mode is :II This book contains the word I Africa ' "(3c). The sentence 3b is in its formanalogous to the sentence" Mr. A visitedAfrica" (3a); but there is a principaldifference between the two sentences.The sentence 3a asserts something aboutAfrica. The sentence 3b-being analogous- seems to assert something about Africa,but really d oes n ot. It is not a quality ofAfrica to be treated of in that book,because one might know everything aboutAfrica and nevertheless nothing about thatbook. I t is only a quality of the wordI Africa' to be contained in the book.On the other hand, it is really a qualityof Africa to be visited by Mr. A. Herewe see the deceptive character of the

"

8. The Mater ial and the F orm al M odesof S Peec h.

All .sentenceaof empirical __cience, allsentences asserting facts, whether they~are general or individual, ~re real object-~entence~. All sentences of logical analy-sis on the other hand, and-as we shallsee in the next chapter-of philosophy,belong to the second or to the third kind.Thus in our further considerations, thesetwo kinds of sentences are chiefly con-sidered. They differ, as we have seen,not so much in their purport or contents asin their formulation. In the mode ofspeech applied in pseudo-object-sentencesthere are used words which designateobjects or matter, while the words usedin syntactical sentences obviously concernfonn. For this reason we shall call thepseudo-object-sentences also sentences ofthe t!!_Cle_riaZod e o f speech , while we shallassign the syntactical sentences to theform al m ode o f speech .The difference between these two modes

of speech may be made clearer by a few

I:I,,IIi I~Ii. I

!

64 65 r.


34/51

As an example of a somewhat differentkind let us examine sentence 4b: HTheevening-star and the morning-star areidentical," or rt are the same thing."This sentence is in its form analogous tosentence 4a: HThe evening-star and theearth are about equal in size"; but 4bis in fact a pseudo-object sentence whichis to be translated into the following syn-tactical sentence (4c): II The words, evening-star' and Imorning-star' aresynonymous." The sentence 4a assertsthat there is a certain relation betweentwo certain objects. The sentence 4bse ems to do the same, but it is obviousthat it really does not. There cannot betw o objects concerned here, because thetwo names designate only one object)namely a particular planet. But not eventhis object is concerned in the sentence4b, for it is easy to see that it does notassert any quality whatever of that planet.It asserts only something about the twodesignations, namely that they designatethe same thing, or, expressed in syn-tactical terms, that they are synonymous.

66

Here we find again that deceptive charac-ter of the material mode as to the subject-matter of its sentences. Most of the sen-

- ___~_ p tences of phi losophy deceive u~ jI_lt}:lis~aY!__~ ~ ~ ~ ~ ~ ~ e - : ~ - ~ _ s _ - - ~ ~ _ - - ~ h - a : i ree, most ofthem are formulated in the material mode~(speech:

material mode; the sentences of this mode.;~~mto'concern something which they infact do not concern.'-.

6 '7

of speech. We have seen how they can


35/51

68

be translated into the formal mode ofspeech, that is, into sentences manifestlybelonging to syntax. These considerationswill be of special importance for such~entences as eXPI~~_r.esults _ _Qi_lQg!g_~~~~X~~s, because those sentences are, aswill be shown, very often, and perhapsfor the most part, ~~t.:es_~edinjhe mi!teIj~~~_ o~~~s:p.. The!!se of_this_.materi.~Jmode often leads to confusion and idle.P~~


36/51

formal mode as: "The word f friendship ,is not a quality-designation but a relation-designation." By this translation itbecomes clear that it is the word' friend-ship' which is here concerned, and notfriendship itself, as is falsely suggested bythe form of the original sentence. To takeanother example, this time arising out ofthe logical analysis of the notion of number,the sentence f f 7 is not a thing but anumber," is merely the expression in thematerial mode of the formal sentence," The sign' 7' is not a thing-sign but anumerical sign."Hence it is apparent that if we wish toavoid the dangerous material mode, wemust avoid the word (thing' and useinstead the parallel syntactical term, thing-designation' ; analogously, insteadof the word' number' we have to use theterm' numerical designation,' instead of, quality,' , quality-designation,' instead of relation,' 'relation-designation,' insteadof ( event,' , event-designation,' instead off space,' t spatial designation' or ' spatialco-ordinates,' instead of f time,' 'time-designation' or 'time-co-ordinates,' andso on. It will be easily seen withoutfurther examples that in this way .~~IlY

70

results of 1_~gi.~~._~_~y._!~_11!m._o~tn .!.a~_tto be syntactical,In the last chapter we showed that the

sentence "This book treats of Africa,"was a sentence of the material mode,capable of being translated into the formalstatement, " This book contains the word( Africa '." Similarly, to the materialmode belong all those sentences whichassert that a certain sentence or treatiseor theory or science d ea ls w ith such andsuch objects, or descr ibes or asserts suchand such facts or states or events; or thata certain word or expression designates orsigni f ies or mean s such and such an object.Among such sentences dealing with thepurport, meaning, or signification of some-thing, especially important are those whichexpress the result of the comparison oftwo theses or two theories or the like,and assert that both have the same pur-port or meaning, or that both express thesame facts or states. For the translationof such sentences into the formal modewe make use of the syntactical term, equipollent' as defined above, andthe assertion becomes: IfThose theses,theories, etc. are equipollent." Analogous-ly. sentences such as " These expressions

71


37/51

have the same signification" or If designate the same object" are translated(according to our definition of the term, synonymous') into the form : If Theseexpressions are s yn on ym o us .'~y this_!I1et~odof translation into the for-mal mode we free logical analysis from all-referelice to the extra-linguistic objects-themselves, and we are then concernedmerely with the fonn of linguistic expres-sions. I t is perhaps hardly necessary toemphasize the fact that this conclusionapplies only to lo g ic a l a n aly sis , and thatthere is no question of eliminating referenceto objects themselves from objec t - sc i ences .On the contrary, these sciences are reallyconcerned with objects themselves, withthings, not merely with thing-designations.

2. Modal i t i e s .Now let us consider some terms of a

quite different kind, the so-called M o da l-ities, namely, possibility, impossibility,necessity and contingency. These ideashave at all times greatly exercised theminds of philosophers. Recently the logicof modalities has been treated with greaterexactitude by means of the construction ofaxiomatic systems in which the modalities

72

are given as principal concepts. But wefind that the authors of these systemsdiscuss certain questions (for instance thatof the true meaning of possibility) forwhich there is given neither an unam-biguous answer nor a method of resolution.In my opinion this is a symptom that inthese systems the logical character of themodalities is not conceived with completeclarity.!1od~lity sentences are in fact veiled

syntactical sentences, namely sentencesof the material mode of speech. Towhat do we usually apply modalities,for instance, possibility or impossibility?We apply them to conditions, states,events, and such like-to take an example,if That A is older than B, and B is olderthan A, is an impossible state." Thissentence can be translated from thematerial into the formal mode in the fol-lowing way: 'The sentence' A is olderthan B, and B is older than A' is con-tradictory." That the term I impossible'belongs in fact to the material mode, maybe easily shown by the criterion previouslyexplained: ~Eossib~_~_!~._~q~_~i~l._.!~~~}~~_._.!.~~~eis a parallel syntacticalqu a l i ty, n a m e l y - c o n t i a d l c t o n i i e s s - ~ - b e c a u s e- ~~------. ._ .. ~.~-.. - .. " . . . . - . . . , , . . , . . - ~-- _. - ~ _,.- .. ..,..-- .~.. . . _ _ - ..~--. . . .

73 n


38/51

always and only when a st~te.~~,~p~_~sibIS,is the sentence which describes this state~ n t r a d lc lo r y , ' a s ,' forInstance: ..~--theexample' given.Sometimes, however, the idea of im-

possibility has the sense not of logical,but of phys i cal or real impossibility. Inthis latter case the parallel syntacticalterm is not ' contradictory Ibut the corres-ponding general term,. namely f contra-valid.' Take for instance the sentence,((The state of a particular solid iron ballswimming on the water is physically im-possible." The translation is: "Thesentence' This solid iron ball is swimmingon the water' is contravalid." Here thesentence is in fact P-contravalid, that is,incompatible with the system of physicallaws.The other modality-terms belong like-

wise to the material mode. As possibilityis the opposite of impossibility, obviouslythe parallel syntactical term to I logicallypossible' is I non-contradictory,' and theparallel syntactical term to f physicallypossible' is f non-contravalid.' Analo-gously, we translate f logically necessary'into I analytic,' and ' physically necessary ,into 'valid.' For instance, instead of

,,

74

saying in the material mode: If That aniron ball is heavier than a wooden ballof equal size, is physically necessary," wesay in the formal mode: (i The sentencef An iron ball is heavier than a woodenball of equal size J is valid." In this casethe sentence is P-valid, that is, logicallydeducible from the system of physicallaws. Finally we have the modality term, contingent' (in the sense of f neithernecessary nor impossible '). We translate'logically contingent' into I synthetic,'and I physically contingent' into I indeter-minate.'Modalityterms

Parallel syntactical termsL-terms General terms

log. or phys.impossible contradictory contravalid

log. or phys.possible non-contradictory non-contravalid

log. or phys.necessary analytic validlog. or phys.contingent synthetic indeterminate

3. Relativity in Regard to Language.Now it may be asked why I repeatedly

propose to translate sentences which areformulated in the material mode of speech

7:;

are class-expressions of the second order " ;


39/51

into the formal mode. I do this for thepurpose of showing that such sentencesbelong to the field of syntax. By theapplication of the material mode thischaracter of the sentences is disguised;we are deceived-as we have seen-as totheir real subject-matter. But there arestill greater disadvantages of the material-~--~... - _ ... _ - - - - - _ . - - _ -~ 9 4 _ ~ _ . " _ " " Itjnvolves the danger of gettin_giIl~ouseless philosophical "-cQi~IiQveisi~s.To take a case in point, in the different

systems of modern arithmetic dealt withlogically, numbers are given differentstatus. For instance in the system ofWhitehead and Russell numbers aretreated as classes of classes, while in thesystems of Peano and of Hilbert they aretaken as primitive objects. Suppose twophilosophers get into a dispute, one ofthem asserting: ' , Numbers are classesof classes," and the other: "No, numbersare primitive objects, independent elem-ents." They may philosophize withoutend about the question what numbersreally are, but in this way they will nevercome to an agreement. Now let themboth translate their theses into the formalmode. Then the first philosopher makesthe assertion: "N umerica1 expressions

and the other says: "Numerical expres-sions are not class-expressions, but elemen-taryexpressions."In this form, however, the two sen-

tences are not yet quite complete. Theyare syntactical sentences concerning cer-tain linguistic expressions. But a syn-tactical sentence must refer to one orseveral specific language-systems; it isincomplete unless it contains such areference. If the language-system ofPeano is called Lv and that of Russell L2,the two sentences may be completed asfollows: "In Ll numerical expressionsare elementary expressions," and: "InL 2 numerical expressions are class ex-pressions of the second order." Now theseassertions are compatible with each otherand both are true; the controversy hasceased to exist.Very often st~I.:il~p'!!~~osghic~!g0!:ltro-

versies arise through such an incomplete-Eess--o~--t"~s~~._""hTs-"'i~~om"pieteness"isconcealed by the usual formulation ill the~a t e r l a i - m o d e : " - - - - W h e u " - " 1 : r a . n s i a t e < I " into. .. . - ._ -_ ._ . .. .. .. . .- -- < .. .- -- ~- . .. .. .. ~ . -. ~. -- -- .- . ..the formal mode, the want of referenceto language is noticed at once. Then byadding such a reference the theses are

76 77


40/51

made complete, and thereby the con-troversy becomes clear and exact. Eventhen it will sometimes still be difficultto decide which side is right; but some-times it is as simple as in the examplejust considered, and the dispute obviouslyvanishes. The relativity of all philosophicaltheses in regard to language, that is, theneed of reference to one or several, par-ticular language-systems, is a very essen-tial point to keep in mind. It is on accountof the general use of the material mode ofspeech that this relativity is nearly alwaysleft unnoticed.

4. Pseudo-questions.In the example mentioned the theses

are only incomplete; they can easily betranslated into the formal mode and com-pleted, and thus they become precise. Inother cases, however,. the use of thematerial mode leads to metaphysicalpseudo-theses which cannot be so easilycorrected. I do not mean that the sen-tences of the material mode are themselvesnecessarily pseudo-theses or without sense,but only that they often mislead usinto stating other sentences or questionswhich are so. For instance, in the

material mode we speak about numbersinstead of numerical expressions. Thatis not in itself bad or incorrect, but itleads us into the temptation to raisequestions as to the real essence ofnumbers,such as the philosophical questions whethernumbers are real objects or ideal objects,whether they are extramental or intra-mental, whether they are objects-in-them-selves or merely intentional objects ofthinking, and the like. I do not knowhow such questions could be translatedinto the formal mode or into any otherunambiguous and clear mode; and Idoubt whether the philosophers themselveswho are dealing with' them are able togive us any such precise formulation.Therefore it seems to me that thesequestions are metaphysical pseudo-ques-tions.If we use the formal mode of speech,

we are not speaking about numbers, butabout numerical expressions. We canthen raise many questions concerning thesyntactical character of the numericalexpressions in a certain system or indifferent systems, but we do not arriveat pseudo-questions of the kind men-tioned. Against these we are protected

798


41/51

automatically, so to speak, by the useof the formal mode.What are the practical consequences of

these considerations as to the formulationof philosophical theses? There is no needto eliminate completely the material modeof speech. This mode is usual and perhapssometimes suitable. But it must behandled with special caution. In alldecisive points of discussion it is advisableto replace the material by the formalmode; and in using the formal mode,reference to the language-system mustnot be neglected. It is not necessary thatthe thesis should refer to a language-system already put forward; it n1aysometimes be desired to formulate a thesison the basis of a so far unknown language-system, which is to be characterized byjust this thesis. In such a case the thesisis not an assertion, but a proposal orproject, in other words a part of thedefinition of the designed language-system.If one partner in a philosophical dis-

cussion cannot or will not give a trans-lation of his thesis into the formal mode,or if he will not state to which language-system his thesis refers, then the otherwill be well-advised to refuse the debate,

because the thesis of his opponent isincomplete, and discussion would lead tonothing but empty wrangling.One frequent cause of dispute amongst

philosophers is the question what thingsreally are. The representative of aPositivistic school asserts: "A thing is acomplex of sense-data;" his Realisticadversary replies: II No, a thing is acomplex of physical matter;" and anendless and futile argument is thus begun.Yet both are right after all; the con-troversy has arisen only on account of theunfortunate use of the material mode.Let us translate the two theses into theformal mode. That of the Positivistbecomes: HEvery sentence containing athing-designation is equipollent with aclass of sentences which contain no thing-designations , but sense-data -designations,"which is true; the transformation intosense-data-sentences has often been shownin epistemology. That of the Realist takesthe form: ((Every sentence containinga thing-designation is equipollent with asentence containing no thing-designation,but space-time-co-ordinates and physicalfunctions," which is obviously also true.In this case we do not even need to refer

. I,


42/51

to two different language-systems in orderto make the two theses compatible withone another. They are right in relationto our general language. Each of themasserts the possibility of a certain trans-formation of thing-sentences. As bothkinds of transformation are found feasible,there is no inconsistency. In the originalformulation in the material mode thetheses seemed to be incompatible, becausethey seemed to concern the essence ofthings, both of them having the form:" A thing is such and such."

5. E pistem o lo gy.So far we have considered several

examples of philosophical questions, andwe have seen that we can translate thesequestions from the commonly used materialmode of speech into the formal mode. Bythe possibility of this translation it isshown that they belong to syntax. Nowthe questionarises whether the .same con-sideration likewise applies to all otherproblems and theses of philosophy, (where, philosophy,' a s explained before, is under-stood to include neither metaphysics norpsychology). It is my contention that itdoes. Let us glance at the principal parts

82

of philosophy in order to exarnme thisassertion.Epis temology or theory of knowledge in

its usual form contains both psychologicaland logical questions. The psychologicalquestions here concern the procedure ofknowledge, that is, the mental events bywhich we come to know something. Ifwe surrender these questions to thepsychologist for his empirical investigation,there remains the logical analysis of know-Iecige:-~imore precisely, the logical analy-sis of the examination and verification of'assertions, because knowledge consists ofpositively verified assertions. Epistemo-logical questions of this kind can certainlybe expressed in the formal mode, becauseepistemological analysis, the question ofthe verification of a given sentence, hasto refer-as we found in the first chapter-to those observation sentences which arededucible from the sentence in question.Thus ! ? ~ " , . ! ? t { i ~ ~ ! ~ ; ! _ l & t Y . i , . _ 2 i _ y ~ r , i f i . s ~ g 9 . ni s . . . t~.~,~.~!!~~f#fE.L.g,JJ1\lY2.!~~9.!.,.t~g~~..r~n~::formation rules which determine thededl!ctlO~'~i'~;er~at1on>-selrte~~;;~H~~~e' epistem_o!ogy. ; "aite~-'''-'~li~i~~-ti~~'~ ;r" its"~ " . . . . . ~ -. .~..metaphysical and psychological elements- is a par t o f syn tax.. .

6. Natural Philosophy. If in natpmJ philosophy we deal, fQ[_


43/51

It may seem, perhaps, more importantto give our attention to some of thespecial divisions of philosophy, than todiscuss the general questions of epistemo-logy. What is called Natural Philosophyis, in particular, attracting more and moreinterest at the present time. What is thesubject-matter of this part of philosophy?Is its task the philosophical investigationof nature? The answer is, No; there canbe no such thing as a philosophical investi-gation of nature, because whatever canbe said about nature, that is about anyevents in time and space and about theirconnections, has to be said by the scientiston the basis of empirical investigation.There remains nothing for the philosopherto say in this field. Metaphysicians do,indeed, venture to make a lot ofstatementsabout nature, but such metaphysics is,as we have seen, not theory, but ratherpoetry. Il:te object ofscientifically treated~_a.t_ur


44/51

of space and time are syntactical questions,that is, questions about the structure ofthe language, and especially the structureof the formation and transformation rulesconcerning space- and time-co-ordinates.In addition to the problems of spaceand time, contemporary natural philo-

sophy is especially concerned with theproblems of causa~.~ty. These problems~.~~..~Y!ltClctica1problems concerning ~~~syntactical structure of the system of. . . . ,. _ -- -'_' _ . - .- .. -.. . . ,.phY~icall':l:ws,as for instance the questionwhether fundamental physical laws havethe type of deterministic laws or that ofmerely statistical laws. This logical ques-tion is the core of the whole problem ofDeterminism, which is nearly always ex-pressed in the material mode, and is inaddition often mixed up with metaphysicalpseudo-problems. Consequently its char-acter as a syntactical problem has notbeen recognized.The objection may perhaps be raisedat this point that the form of physicallaws depends upon the experimental re-sults of physical investigations, and thatit is not determined by a merely the-oretical syntactical consideration. This

in mind the fact that the empirical resultsat which physicists arrive by way oftheir laboratory experiments by no meansdictate their choice between the determin-istic and the statistical form of laws. Theform in which a law is to be stated has tobe decided by an act of volition. Thisdecision, it is true, depends upon theempirical results, but not logically, onlypractically. The results ofthe experimentsshow merely that one mode of formulationwould be more suitable than another,that is, more suitable with regard to thewhole system of physics. However closethe practical connection between theempirical results and the form of physicallaws may be, the question concerning theform of these laws is in every case a syn-tactical question, that is, a question whichhas to be formulated in syntactical terms.It is, to be sure, a syntactical question

concerning a language-system which hasnot yet been stated, but is still a matterofdiscussion. And in this discussion aboutthe future form of physical language andespecially the form offundamental physicallaws, physicists as well as logicians haveto take part. A satisfactory solution can

86 87

only be found if both points of view, the ar~_th~__q u estio ns ...as.-tQ _Jh ~__ch._~I.~.


45/51

empirical view of physics and the formalone of syntax, are taken into consideration.This applies not only to the specialproblem of causality and determinism,but generally to all problems of naturalphilosophy, to all questions of the logicalanalysis of empirical science. All suchquestions are syntactical problems, butin their treatment the results of empiricalinvestigation have also to be taken intoconsideration.

88

the terms contained therein, the characteroftnesentences, -~nd'~b~;~'-alithe tr~n;-f o r m a tiori--oi'-tr~~i~ti~~-~~i~~-~~~n~~~-ti~g{haflariguage' . \ y f t . ! i ~ i ~ ~ . :.-~~t! i~i~=~E~.~l~languages.ithat is, with the other part-;ysteiris'~of- the whole language of science.Of these languages the physical, or thatin which we speak about physical thingsin every-day life or in physics, is of thegreatest importance. In our discussionsin the Vienna Circle we have arrived at

.. .... t ....... ~ .. ,_ . __ ----the opinion that this physical languagei . s , . ,!~.~.~.~~}~~.l1g~~_~..g_~.~~1[~~gfe;-tliarit is a universal language comprehendingthe contents of all other scientific lan-guages. In other words, ~.:y~.ry.~~~.tenceof any branch of scientific languageiis.. ---.,._--_ .. _ . . .. . ;. ... ,. _. _ _ . _ . _ ... --_ .. . ,. -. ,. . . . --.~ . . . . . . . . . ..equipollent to so~e. sentence of thep!iysic;~il-l~iUage, and can therefore betranslated into the physical language with-out changing its content. Dr. N eurath,who has greatly stimulated the considera-tions which lead to this thesis, has pro-posed to call it the thesis of physicalism.For purposes of elucidation, let us take

the following psychological statement: " Atten o'clock Mr. A was angry." The equi-pollent sentence of the physical language

89

7. What Physicalism Asserts.As there is no philosophy of nature,but only a philosophy of natural science,

so there is no special philosophy of lifeor philosophy of the organic world, butonly a philosophy of biology; no philo-sophy of mind, or philosophy of thepsychic world, but only a philosophy ofpsychology; and finally, no philosophyof history or philosophy of society, butonly a philosophy of historical and socialsciences; always remembering that thephilosophy of a science is the syntacticalanalysis of the language of that science.The principal problems concerning such

a language of a certain region of science-. . .

is: II At ten o'clock Mr. A was in a certain the only assumption is tha t it is valid. J t


46/51

bodily condition which is characterizedby the acceleration of breathing and pul-sation, by the tension of certain muscles,by the tendency to certain violent be-haviour, and so on." Let us express thequality of being angry by the symbol, Q1,' the above described physical qualityof a body by I Q 2 " and the time of ten0'clock by I t1.' Then we may write thetwo sentences symbolically in the followingway:

(Psychologi

carnap - philosophy and logical syntax

Documents