a naturalistic a priori

GEORGES REY

A NATURALISTIC A PRIORI1

(Accepted 8 August 1997)

It is widely believed that the possibility ofa priori knowledge isincompatible with a naturalistic epistemology, or an epistemologythat treats human knowledge as entirely explicable as a phenomenonin the physical world. Quine (1953, 1960, 1969) is best known foradvocating this view, Fodor and LePore (1991) have risen to defendit, and in Michael Devitt’s recentComing to Our Senses(1996), ithas achieved a practically definitional status. There he identifies thenaturalism that he endorses as the view that:

there is only one way of knowing, the empirical way that is the basis of science(whatever way that may be). So I rejecta priori knowledge. (p. 2)

Of course, he isn’t offering a gratuitous stipulation. He gives tworeasons for thinking of naturalism in this way:

First, with the recognition of the holistic nature of confirmation, we lack a strongmotivation for thinking that mathematics and logic are immune from empiricalrevision; and

Second, the idea ofa priori knowledge is deeply obscure, as the historyof failed attempts to explain it shows. (p. 2)

He repeats and develops these two points in his §2.2 (pp. 46–54),criticizing in passing an earlier paper of mine (Rey, 1993) thatattempted to show the contrary.

In that earlier paper, I defended the possibility of analytica prioriknowledge against both Quine’s and Fodor and LePore’s attacks. Iclaimed that whether or not there isa priori knowledge is an empir-ical issue not settled by the familiar, but insubstantial observationsabout “revisability” and “confirmation holism” that are frequentlyinvoked against it. For all that any of the critics have said, it maywell turn out to be an empirical, and entirely naturalistic fact thatwe humans possessa priori knowledge in a number of areas.

Philosophical Studies92: 25–43, 1998.© 1998Kluwer Academic Publishers. Printed in the Netherlands.

26 GEORGES REY

In this paper, I want to address the above two reasons of Devitt’sfor rejecting a naturalistica priori. I shall reiterate the main pointsI set out in my earlier article, but also try to make clearer than Imay have there just how a reliabilist theory of knowledge offers acrucial alternative to the more traditional conceptions that botherDevitt (the present paper however will not presuppose any of thisearlier material). In §I below I shall reply to the first of Devitt’sreasons, showing that, widely accepted appearances to the contrary,Quine’s suggestions about “confirmation holism” have by no meansremoved all of the motivation for positinga priori knowledge. In§II I shall set out once again my positive account, adding in §IIIsome suggestions about how it might be extended to account foranalytic a prioriknowledge, or knowledge based upon a knowledgeof meaning alone.

I. REVISABILITY AND CONFIRMATION HOLISM

Quine’s (1953, 1956, 1970/78) picture of knowledge should be quitefamiliar: our beliefs about the world form a seamless web, any singlestrand of which may be modified to preserve certain overall proper-ties of the web that are compatible with the experiential periphery.The traditional claims of logic, mathematics and philosophy are nodifferent in kind from beliefs about theoretical physics, biology oreven just commonsense claims about the everyday world, any oneof which can be revised in the light of experience.

Why is this picture so intuitively appealing, almost entrancing?I submit that it’s in part because it’s kept so comfortably out offocus, sustained by three claims whose appeal also depends upontheir being kept at a blurry distance as well. The three claims are:2

(1) revisability: any belief can be reasonably revised in the light ofexperience;

(2) isotropy: any belief is potentially relevant to the confirmation ofany other belief; and

(3) globality: the plausibility of a belief should be assessed in thelight of the plausibility of thewholeof one’s beliefs;

Revisabilityis plausible in view of what I call “banal fallibal-ism”: people could be wrong about most anything; they can make

A NATURALISTIC A PRIORI 27

errors in reasoning, rely on experts that mislead them, or just reasonthemselves into strange corners. Indeed, there seems to be no claimthat someone bright and imaginative enough couldn’t render plau-sible with enough revision of the rest of his belief system. Witnessthe often well thought-out delusions of brilliant paranoids, and orthe preposterous claims that have been advanced by one or anotherphilosopher.

Isotropyis a kind of safe generalization of revisability: since thereseem to be endless ways in which one’s beliefs could be adjusted soas to justify the revision of any particular one of them, any beliefis (or, anyway, ought to be regarded as) potentially relevant to theconfirmation or disconfirmation of any other. At any rate, given thatchains of reasoning seem to be extendable in any number of direc-tions, it would be rash to set limits to any such potential connections.If the peculiar additive properties of mercury (adding one drop toanother yielding still one drop) were sufficiently pervasive in nature,perhaps someone might reasonably wonder whether 1 + 1 was reallyequal to 2. In fact, of course, bizarre results in quantum physics haveled people reasonably to consider revising elementary logic.

Before turning to the third, and most important claim aboutholism, globality, it is extremely important to observe that, contraryto much received opinion,these first two claims have absolutelynothing to do with the a priori! Claims to thea priori need havenothing to do with ways one might revise and justify any of one’sbeliefs in the light of experience. Thea priori doesn’t concern thenature of empirical knowledge at all, but rather whether one mightalsobe able to justifysomeclaimsnon-empirically, “independentlyof experience.” This is, after all, how the standard definition of thea priori reads. Plato, Leibniz, Kant never to my knowledge talk ofunrevisability, much less of non-isotropy: they know only too wellhow people (in what they might have regarded as the darkness ofthe experiential cave) might be rationally misled in any number ofways. Talk of unrevisability (and/or non-isotropy) as a criterion ofthea priori is a quite recent, Positivistic, specifically behavioristicway of talking – it’s supposed to afford an easy “operational” testof the distinction. But we all know better than to base philosophyon operational tests. In general, they tend to suffer from what I call“superficialism,” an insistence on surface criteria that can conceal

28 GEORGES REY

important distinctions that a deeper analysis might reveal.3 What-ever else may be true of thea priori, this association of it withunrevisability and non-isotropy really should be dropped. To repeat:thea priori is an issuenot about how beliefs could reasonably ebband flow with experience, but simply about oneparticular sort ofjustificationthat appears to be available in logic and mathematics.

Of course, someone might point out that some revisions may bedue merely to recognizing errors in reasoning, whereas others – theones that really concerned Quine – may have to do with the actualevidential bearing of experience upon the truth of a claim (see e.g.Field 1996). However, it is not clear that this is a distinction onwhich an opponent of thea priori can uncritically rely. For thedistinction between matters of empirical evidence and matters ofreason alone is precisely what the Quinian sceptic about thea prioriis challenging. If this distinction is to be available to distinguishdifferent sorts of revision, why shouldn’t it be available to distin-guish “knowledge based upon experience” from “knowledge basedon reason alone”?

It is important to note here that, also contrary to common opin-ion, traditional philosophers needn’t be particularly fazed by thefamiliar revisions ofa priori claims occasioned by empirical sci-ence. They can regard the proposed revisions of, e.g. Einsteinregarding space, or quantum physicists regarding logic, as involv-ing simply the exhibition of some furthera priori possibilities thatprevious philosophers had missed, rather in the way that Gettier(1963) thought of certain counterexamples to traditional philosophi-cal analyses of ‘knowledge’. After all, what is essential to the defeatof e.g. Kant’s claim about thea priority of Eulidean geometry is notthat actual space turns out to be Riemannian, but that itcould be(note that, at least in the case of the geometry of space, it was notEinstein, but puremathematicianslike Riemann and Lobatchevskythat began to refute Kant on his owna priori ground). Indeed, adefender of thea priori can quite plausibly argue that the revisionof any claim about a pure (non-indexical4) necessarytruth couldnever really depend upon anyone’s actual sensory experience, since,at best, all that such experience can provide of relevance to that truthis the presentation of the actual as simply one among the manypos-sibleworlds that the pure necessary truth concerns. A pure necessary


truth is not a claim about anythingidiosyncraticto the specific worldwe experience; so how could its justificationdependin any essentialway upon the character that world happens to present to us?

Of course, the issue of the general nature of justificationis pre-cisely what is addressed by the third claim associated with holism,globality. But here, too, a banal claim is easily confused with some-thing more controversial. The banality is that one should in principlekeep track of the plausibility of the whole of one’s beliefs: oneshould take account of the consequences of one’s beliefs upon otherbeliefs and the overall plausibility and coherence of one’s storyof the world as a whole. Who could deny it? Certainly none ofthose traditional philosophers – who tended to be a lot more self-conscious than most of us about the whole of their beliefs. Sowhy didn’t they give up on thea priori for this reason? Obviouslybecause they thought that, reflecting on the whole of their under-standing of the world, the most plausible story was that people hada priori knowledge of logic, mathematics and much of philosophy.And they had theories of how this was possible. What divides themfrom Quine and Devitt is not globalityper se, but whether globalityis theonly method of justification. But before we address that dif-ference, we need to get clearer, if we can, about just what the issuesare.

It is true, as Devitt (1996, pp. 50–4) emphasizes, that traditionaltheories ofa priori knowledge were far from satisfactory. Appealsto some special faculty ofa priori intuition capable of unproblem-atically apprehending clear and distinct ideas, or forms in Plato’sheaven, do seem little better than theological claims about the deliv-erances of revelation. And Positivistic appeals to truth by conventionwere a scandal, as Quine (1956) brilliantly showed.5

However, in fairness, one ought to go a little easy here. The prob-lem of our knowledge of mathematics and kindred areas in one ofthe central and most difficult problems in the history of Westernphilosophy. Come to think of it, so is the problem of knowledgegenerally.No one yet has an adequate theory of our knowledge ofmuch of anything! Certainly none of us should be under any illusionthat Quine’s “confirmation holism” amounts to any such theory. Atits best, it amounts to five vague “virtues of hypotheses” – simplic-ity, generality, modesty, conservativism, falsifiability – that Quine

30 GEORGES REY

and Ullian (1970/78) set forth in a freshman text on reasoning.6 AsQuine, himself, admits: “I treated it mainly at that level becauseI have been little to say of it that was not pretty much commonknowledge” (1986, p. 493).

It is easy to underestimate the extent of our ignorance in thisregard. Despite acknowledging our lack yet of an adequate accountof either the metaphysics of mathematics or an epistemology ofeven empirical knowledge, Devitt thinks Quine has shown that “themotivation to seek ana priori way of knowing is removed,” since:

what we do have is an intuitively clear and appealing general idea. It starts fromthe metaphysical assumption that it is the worldly fact that p that makes the beliefthat p true. The empiricist idea then is that experiences of the sort produced bythat fact are essentially involved in the justification of the belief. (p. 50)

But this is a strange line of thought. In the first place, it may well betrue thatempiricismhoped that an account ofempiricalknowledgewould proceed causally from the external world – but what doesthis have to do particularly withnaturalism, or with confirmationholism? One would have thought – Quine certainly seems to think– that the vague holistic virtues like simplicity, etc., enter the pic-ture precisely when causation from external stimuli alone peter out.It may well be that the curvature of space/time lies in a chain ofcauses at the other end of which occurs Einstein’s general theory ofrelativity, but I wouldn’t describe this as an “intuitively clear andappealing” answer to how Einstein’s knowledge was possible. Nordoes saying that it was the “simplest,” most “conservative,” most“falsifiable,” etc. hypothesis make things really much clearer. Ein-stein’s theory – or present quantum theory – is simpler and moreconservative only to averysophisticated palate.

But, however obscure a causal-cum-Quinian account ofempiri-cal knowledge remains, why on earth think it helps with logic ormathematics? How does Devitt hope to solve the epistemic prob-lems here by a causal theory of knowledge without,by his ownadmission, any account of the metaphysics of mathematical facts,and so,a fortitori, of how possibly they could be causally effica-cious? How do the “events” of unmarrieds being unmarried, or theinfinitude of the primes (if “events” are what they are) enter intocausal relations at all? In any case, while there might be some peoplewho arrive at logical truths by causal interaction with the empirical


facts engendered by them, notoriously, this is not the way most of usdo. Nor does it really seem that, à la Quine, we just sort of “roundout” our theory of nature with them, rather in the way that we roundthings out by believing material objects persist unobserved.

Moreover, of course, there is the further fact, striking to every-one who has thought about the matter, that truths of logic andmathematics seemnecessary, the denials of at least the basic onesunintelligible. That is, unlike the supposition of persisting materialobjects, we have trouble even making any realsenseof the denialsof basic logic and math, and it isthis– not pragmatic considerationsof simplicity and rounding things out – that really seems to be thesource of our belief in them. How does Quine’s holism, or a causaltheory of knowledge, help us understand this crucial feature? Oris thenecessityof a necessary truthalso somehow acauseof ourbelieving it?

Traditional accounts of our knowledge of logic and mathematicshave indeed been obscure. But no one should be under any illusionthat Quine’s account is really any better. At best, it avoids obscu-rity only by so distancing the issues that all the crucial details arelost. Or, worse, he tries to spell out his epistemology in terms of atheory of conditioned responses. Here, vagueness is reduced onlyby the introduction of empirical falsehoods and patent explanatoryfailures.7

But my quarrel here is not merely with the vagueness and inad-equacy of Quine’s account. Let him who has not been vague inepistemology cast the first stone. My real quarrel is with the moreserious illusion that “the motivation to seek ana priori way ofknowing is removed” by Quine’s account: that Quine has providedenough to show that there is noa priori knowledge at all. Surely hehas shown no such thing. The vagueness alone of Quine’s accountleaves the issue still wide open. Who knows whether in spelling outthe various virtues of “simplicity,” “generality”, etc. and in explain-ing people’s grasp of logic and mathematics, all rational assessmentsof theories may not operate under various constraints that will afforda basis fora priori claims?8

Of course, Quine did make itappearthat the issue was closed.People entranced by his holistic picture of confirmation seldom note

32 GEORGES REY

that, slipped into his famous statement of it, is an absolutely crucialword: ‘only”:

Our statements confront the tribunal of experienceonly as a corporate body.(1953, p. 38, italics mine)

It is on this single word that the whole of Quine’s supposed refuta-tion of the a priori depends: it is only the word ‘only’ that changesa banal claim about global assessment into a claim that there is nomore local way of knowing. For, as I have already indicated, it isopen to all those traditionala prioristicphilosophers to concede thatall our beliefs are revisable, isotropic and globally assessable,allthe while insisting that there are (and perhaps even must be) alsoentirely local, a priori justificatory means!

But what on earth entitles Quine to his ‘only’? How could anyoneclaim for so patently vague and inadequate an account of holisticconfirmation that it was also theonly such account? To make atimely comparison, it is as though someone were to say, “I knowhow to solve the Balkan problem: everyone ought to sit down andtalk things out (after all, most anyone might have something usefulto say); and we should decide on the best (simplest, most conser-vative, etc.) policy overall.” Well, perhaps that would beoneway.But hopefully it is not theonly way. One would certainly want avery powerful argument to establish that it was. Lacking one, we dobetter to explore more local conciliatory, and confirmatory, means.

II. TOWARDS A NATURALISTIC A PRIORI

Could there be a plausible positive account of thea priori? In myearlier paper, I tried to set out such an account, but Devitt foundit insufficiently positive.9 At the risk of repeating what I wrote inthat earlier paper, but to make the positive character of the proposalperfectly clear, let me go over its main points.

Needless to say, by ‘naturalism’ I don’t mean what Devitt claimsto mean, viz. an account that denies that there is such knowledge.The naturalism that I assume is Quine’s own,10 where, in particular,a “naturalized epistemology” is

a chapter of psychology and hence of natural science. It studies a natural phenom-enon, viz., a physical human subject. This human subject is accorded a certain


experimentally controlled input – certain patterns of irradiation in assorted fre-quencies, for instance – and in the fullness of time the subject delivers as output adescription of the three-dimensional world and its history. (1969, pp. 82–3)

Now, I don’t join Quine in his peculiarly behavioristic reading ofthis chapter of natural science. But I do join him in thinking thatepistemology may be part of an empirical psychology. Whether ornot there is anya priori knowledge at all, specificallyepistemologyis not be pursued in the purelya priori fashion that is typical ofmuch traditional discussion.11 It is to be heavily informed by empir-ical theories of methods of belief fixation, and – many, I think, areinclined to add – by a sensitivity to the actualreliability of variousmethods for the kinds of problems that human cognition must solve.

Indeed, a naturalistic epistemology invites a “reliabilist” accountof knowledge, along the lines that have been developed by a numberof writers since Quine (e.g. Goldman, 1967; Dretske, 1971; Nozick,1981). To a first approximation, someone knows that p iff p is true,and her belief that p has been produced by reliable processes: at leastin the relevant circumstances, the processes are such that a persontends to believe that p on their basis iff p is true. I don’t want to pre-tend that this account is awholelot better off than the Quine/Devittaccount, or any other accounts of knowledge. But insofar as it hasmany things to be said for it, and is plausibly naturalistic (in Quine’ssense), it seems to me worthwhile to show how it can accomodatethea priori.

Briefly, and as merely the beginning of a proposal: suppose thatas a matter of contingent fact our brains are so organized that wehave a little sub-system that is capable of grinding out the theoremsof first-order logic. For simplicity, suppose it is a non-axiomaticsystem of natural deduction, relying entirely on the operation ofstandard rules likemodus ponens, universal generalization, condi-tionalization, etc., so that theorems may be identified as lines of aproof with null premise numbers. And suppose that someone, Ellen,was caused to believe, say:

(R) Nothing bites all and only those things that don’t bite them-selves

purely as a result of the operation of this system.Now, why shouldn’t this belief of Ellen’s count asa priori knowl-

edge? Note, first, that it would seem to meet the usual definition

34 GEORGES REY

of a priori knowledge. It would bea priori because it would bea belief whose justification did not depend upon experience: anysuch assumptions that might have been made in the course of theproof were made only “for the sake of the argument,” and were“discharged” in the usual way, e.g. by conditionalization, yieldingclaims with null premises. And it would beknowledgebecause eachof the rules she used were surely justified if anything is. As sound-ness proofs of first-order logic show, they are, indeed,absolutelyreliable in this sense:it is impossible for them to produce a false-hood as a theorem. If empiricial knowledge can be the result of aprocess that reliably – i.e. non-accidentally – issues in true beliefsin relevant circumstances, why couldn’ta priori knowledge be theresult of a process that reliably issues in true beliefs inall possiblecircumstances?

Devitt complains that in this account I have:

failed to show that the output [of my logic sub-system] is knowledge rather than,in the relevant sense, “a mere accident.” It is not sufficient to say, as he does, thatthe sub-system isunaffected by any sensory input. . . [this] does nothing to showthat the outputis justified. (p. 51, fn 2)

Now, the whole point of appealing to the operation of a sub-systemoperating according to logical rules was to establish that beliefssuch as Ellen’sweren’t “merely accidental.” However, in furtherdiscussion, Devitt and Hartry Field have convinced me that I needto say something more: while it’s true that Ellen’s following rulesof logic might make her absolutely reliable, still one might feel thatthis reliability alone doesn’t establish the right kind ofconnectionbetween her resulting beliefs and their objects. After all, perhapsshe is simply a remarkably luckyguesserabout logical truths, andone has trouble ruling out such a possibility in this case, since coun-terfactuals involving the negations of logical truths (“Well, were (R)not a logical truth, she would still believe it”) are, to put it mildly,difficult to evaluate. Or perhaps she is also born blindly believingsuch necessary truths as that water is H2O and salt NaCl; surelythese latter beliefs would hardly count as knowledge, much lessapriori .

But, of course, the relation I am imagining between Ellen’s logicsub-system and the actual truths of logic isnotaccidental. Althougha full account of why this is so would require settling a number of


difficult issues about the metaphysics of logic that (to put it mildlyyet again) are beyond my present ambitions, here’s one story thatshould be naturalistic enough for at least the likes of Quine andDevitt. Take a language to be a recursively specified set of typesentences that exist whether or not anyone has ever produced atoken of them, and imagine that, along familiar Tarksian lines, wedefine what it is for them to be true-in-that-language. I presumethat such sentences consist of sequences of operators (connectives,quanitifers) and referential devices (predicates, variables). The logi-cal truths are those sentences that are true by virtue of the pattern ofoperators alone, independently of the assignments to the referentialdevices: i.e. they are true “merely by virtue of their logico-syntacticform.” Put another way: whatexplainsthe truth of the logical truths,whatmakesthem true, are just those patterns.12

Staying at the level of psychological explanation, by virtue ofwhat properties does she come to have such a belief? If the logicalsub-system operates along the lines of a system of natural deduc-tion as I have stipulated, then it would appear to bethe very samelogico-syntactic propertiesthat make the sentences true. After all,the rules of natural deduction are designed to be sensitive only tothe logico-syntactic form of the sentences on which they operate. Ifa mechanical system realizes those rules, it does so by virtue of therebeing causal transitions between tokens of the sentence types thatare brought about by virtue of the physical properties that realize therelevant logico-syntactic properties.13 Consequently, Ellen’s logicsystem does not issue in truths by accident: indeed, it is sensitiveto – it “tracks” – precisely the kinds of properties and facts thatare wholly responsible for the truth of the sentences it produces.Needless to say, this wouldn’t be true if Ellen were merely a luckyguesser; and such a story is not available for “empirical necessities”such as that water is H2O, or salt NaCl.

Of course, the system might not operate as it is supposed to,i.e. as it does under appropriate psychological idealization. Due todrugs or drink or mere absentmindedness, Ellen’s brain might failto note an undischarged premise, or misapply a rule. But that is noreason to think Ellen’s belief isn’ta priori in a normal case. It’s notthat the sub-system itself isalwaysreliable, making Elleninfalli-ble about such things; rather, it’s reliable,ceteris paribus, making

36 GEORGES REY

her absolutely reliable under the appropriate idealization of the sys-tem, when nothing interferes.14 (Note this is not question-begging:a system of inductive logic might also be described in this idealizedway, without, however, it being absolutely reliable even then; and,of course, its theoremswouldpresumably depend upon experientialpremises).

Someone might worry (perhaps this is Devitt’s worry) that inorder for Ellen to be justified in believing R by application of therules of logic, she must have available to herself the justification ofthose rules, and, if Quine is right, they would be justified only on thebasis of their general coherence with experience. If so, then it wouldseem her justification for believing R would be empirical after all.

But this would miss the heart of the reliabilist move. The relia-bilist wants to supplement the traditional conception of justificationin terms of introspectible first principles by a conception of justifi-cation being established by processes that are in fact reliable. Thereliabilist epistemology is, if you like, grounded in metaphysics, notin some special Cartesian epistemology.15 Consequently, a personmay be fully justified in believing something as a result of usingcertain reliable rules, without having any idea about how to establishthat the rules are in fact reliable; they may be reliable without her(or anyone) knowing they are. This is, of course, connected to thereliabilist’s denial of the “KK principle”: a person may know that pwithout knowing that she knows. Indeed, someone mightthink sheknows that p, even think that p follows from self-evident principles,but, lacking a reliable backing, she might not know p at all, neitherempirically nora priori.

The position in which a knower is left is, on my account, a lit-tle like the position of Lewis Carroll’s (1895/1995) tortoise, whowonders whether a logical principle is true, and insists therefore onwriting it down as a further premise in an argument. Of course, itis interesting to wonder what justifies logical rules, and what onewould say to a doubter of them. But none of this implies that thetortoise and the rest of us aren’t fully justified in drawing a conclu-sion by logical rules without any such premise.Modus ponensisvalid (if it is), and therefore absolutely reliable, quite independentlyof whether anyone has shown it to be.


III. MEANING

How might my account be extended to provide for the analyticapriori? It’s not hard to see at least one strategy that would be com-patible with many traditional conceptions of meaning.16 To followup a proposal of my earlier paper,17 having a concept might involvehaving a file associated with a symbol. In the file are various slotsfor different kinds of information associated with the concept andits extension: common beliefs about things of that sort, rememberedexemplars, derivative prototypes. Arguably, a crucial slot for theidentityof the concept, a constitutive condition of its being the con-cept it is, is one that provides a rule for determining the extensionof the concept in all possible circumstances. Call such rules, M-rules. They are a little like Carnap’s “meaning postulates.” However,unlike Carnap, I see their role as determined not by conventionalchoice, but by psychological fact: they play the right role in aperson’s psychology, distinguishing semantic from mere epistemicvariation in belief revision.

Of course, showing that there is a distinctive role for suchM-rules, as opposed to other contents of a file, is no easy matter.Levine (1993, pp. 122–126) rightly complains of the lack of a satis-factory account in this regard in my earlier account. However, boththere and here I am not concerned to show that such M-rules dopossess such a distinctive role, but only that,werethey to play suchroles, they could afford a basis for analytica priori knowledge in away that need pose no threat to a naturalized epistemology.

Indeed, suppose that someone’s belief were a causal consequenceof M-rules being processed by the aforementioned logic sub-system.Suppose for example, that the M-rule for the concept of the number,[1], specified that 1 the successor of 0, and, for [2], that 2 was thesuccessor of 1. Applying a little logic (with identity), a person pos-sessed of those concepts might conclude that 2 was the successor ofthe successor of 0. Now, she would appear to be doing this withoutrelying on any empirical premises: the M-rules and a little logicwould be enough. But, most importantly, she would have arrived atthis belief by a process that was alsoabsolutely reliable: by means ofthis process,ceteris paribus, she couldn’t possibly go wrong. Afterall, ex hypothesi, if according to the M-rules she deployed, beingthe successor of 0 really is constitutive of being 1, and being the

38 GEORGES REY

successor 1 is constitutive of being 2, then her belief is necessarilytrue; and it was arrived at, again, by a process of logic that is itselfabsolutely reliable and non-accidentally related to the conditionsthat explain how such claims are true. We may even assume thatthey are fully perspicuous to her, that she, herself, finds them (inPeacocke’s (1992) phrase) “primitively compelling,” necessary, andperhaps evena priori. So why shouldn’t the beliefs that result fromthe processing of such M-rules by her logic sub-system also countasa priori knowledge?

Of course, again, from the fact that Ellen’s beliefs might be pro-duced in this way, it doesn’t follow that she herself wouldknowthat they are, or know that the beliefs produced in this way areapriori . She may not have a clue about even what the rules are thatgovern her reasoning (although she may nonetheless find certainparticular transitions compelling and apparentlya priori). They maybe as hidden from her as the rules of a Chomskyian grammar arefrom Chomsky, or the “philosophical analyses” sought by traditionalphilosophers have been to them. As Devitt quite rightly stresses,there doesn’t seem to be any “direct route” to such semantic orphilosophical knowledge of the sort that those he calls “Cartesians”seem to suppose (1996, p. 28). In terms of a reliablist account, thereseem not to be reliable introspective mechanisms by which we mightconsciously access either the synactic or semantic rules of our nat-ural language, or the M-rules that govern our concepts. They maybe, in Stich’s (1978) phrase, even “sub-doxastic.”

Notice that, if M-rules are as sub-doxastic or otherwise as inac-cessable as I suppose, this would allow their presence to be perfectlycompatible with the Quinian revisability that is too often directedagainst them. Unaware of those rules, we may offend against themin all manner of ways in our ordinary and philosophical thought,sometimes explicitly denying the very M-rule that is nonethelesscontrolling our thought (just as Chomsky might happen to reject inprint the very grammar of his own idiolect). And it could even befully rational to do so: just as Chomsky might have excellent, evenif misleading evidence against what turns out to be the very grammarof his own idiolect, so might someone have excellent reason to rejectthe very M-rules that control his concepts.


Indeed, someone might even knowa priori that p but still berationally misled to revise it on the basis of experience. I mightcorrectly make a calculation on the basis of logic and arithmeticM-rules, but have so little confidence in my abilities that I am easilypersuaded on inductive grounds that someone else’s computationis better (she’s usually quite reliable, but not in this case). Thus,contrary to Levine (1993) and many others, it’s simply not true that“in order for the belief that bachelors are unmarried to count asapriori , it must beirrational ever to deny it” (Levine, 1993, p. 124).Again, the analytic a priori has nothing to do with unrevisabilityof belief: something can be a piece ofanalytic a priori knowledgeand be revisable; and, conversely, something can be unrevisable andnot remotely analytic ora priori (for example, the existence of theearth for more than 10 minutes). On my account, thea priori has todo with nothing so shallow as what one happens to believe, but onwhat deeper processes and principles could justify a belief.18

In its rejection of these KK principles and of a Cartesian episte-mology, there is no doubt that my account of thea priori deviatesslightly from the traditional conception. Maybe some will regardwhat I offer as therefore no sort ofa priori knowledge at all. I don’twant to quibble over the term. It is enough for my purposes thatit is possible for there to exist a king of knowledge that fits thestrict traditional definition, accounts for the special epistemologyof, e.g. logic and mathematics, and is compatible with a naturalizedepistemology of the sort proposed by Quine.

Besides rejecting KKism and the Cartesian conception of theapriori , another way in which my account deviates from traditionalones is in having no ambitions to ground necessity somehow inaprioricity, or to otherwise epistemologize metaphysics. My relia-bilist account ofa prioricity obviously presupposes and so couldnot explain necessity (which I doubt one could hope to “explain”anyway). Indeed, it is no part of my claim even to explain thetruthof certain claims by appeal to meaning, whateverthat would cometo. It’s enough for me that certain claims areknowable a prioribyvirtue of their meaning and the reliability of logic alone.

Lastly, my account also abandons the ambition to ground theanalytic itself in thea priori. Levine (1993) seems to have misunder-stood my earlier position on this point, claiming, in his exposition

40 GEORGES REY

of it, that “once we have a working notion of thea priori, it is pos-sible to introduce a notion of the analytic in terms of it” (p. 118).That might well be true, if one had a way of defining the analytica priori without appealing, as I have, to M-rules. I am presum-ing (perhaps precariously) that it’s the M-rules that will receivesome independent specification in terms of their role in a person’spsychology.

Let me end by supplementing Quine’s picture with my own: sup-pose we muddle about à la Quine in the middle of things trying toframe an adequate theory of everything – that is, we begin as epis-temic holists, for lack of anything clearer. But then we notice thatcertain necessary truths emerge from our best theory, and that, more-over, people have extraordinarily reliable sub-systems that issue inmany of these necessary truths. Some of these are due to the factthat, according to the best empirical psychology, certain transitionsin thought are meaning constitutive: they are expressive of rulesthat govern the use of the concepts. We didn’t know introspectivelywhat those rules are, but our holistically justified, empirical pychol-ogy tell us. Once it does, we discover that there are therefore otherways to justify some assertions than by the holism we initially em-ployed. We thus arrive, perhaps with some irony, at a defense ofthe verya priori knowledge Quine and Devitt abjure, but by usingthe very empirical means that they favor. We throw away Quine’sconfirmation holism after climbing up it.

NOTES

1 This paper grew out of a reply to Devitt’s (1996) criticisms of my (1993), whichwas presented in a conference on Devitt’s book at the University of Maribor,Slovenia, in June 1996, and which (in a form focusing exclusively on Devitt) willappear in the proceedings of that conference inActa Analytica. I want to thankthe organizers of the conference, Dunja Tihomorovic and Nenad Miscevic, aswell as many of the participants in it – particularly Joe Levine, Barry Loewer, andMichael Devitt himself – for their reactions and suggestions. Further discussion ofthe topic took place at the D. C. Williams Conference on “Naturalism, Analyticityand theA Priori,” at the University of Maryland at College Park in April 1997,at which Hartry Field made particularly useful remarks. I am also grateful toJohn O’Leary Hawthorne for his invitation to include this paper in the presentcollection, and for his very useful advice on an earlier draft. As usual, I am alsoindebted to Karen Neander for perceptive comments.


2 The last two were usefully distinguished by Fodor 1983, whose terminology Iadopt.3 I discuss and criticize “superficialism” in different connections not only in my(1993), but also in my (1995, 1996a). See Dennett (1995) for a defense of theview in psychology, which I further criticize in Rey (1996); and Peacocke (1996)for a defense of it in semantics, which I will address below.4 That is, putting to one side the complex cases afforded by proper names andnatural kind terms, where, arguably, necessary truths generated by experience(e.g. water is H2O) depend upon some sort of indexical character of those terms, acharacter not obviously present in more traditional cases of arithmetic and logic.5 In Rey (1993:§II), I defend Quine’s attack on convention as the source of theapriori . Required reading for anyone tempted by “truth by convention” is particu-larly Quine’s (1954/1976:§IV) masterly diagnosis of four of its confused sources.6 The virtues are sketched more briefly in Quine (1955/1976, p. 247).7 I examine his account in detail in Rey (1993, §V). See also standard texts oncontemporary psychology (e.g. Gleitman, 1986), or my Rey (1997, ch. 4) forsummaries of the overwhelming empirical case against scientific (or “radical”)behaviorism generally.8 Another motivation which there is not space to explore here is afforded by thecommitments of semantic molecularism, or the view that the meaning or contentof a symbol depends upon its inferential connections with other symbols, in a waythat Devitt (1996, ch. 3) himself endorses. As Levine (1993, forthcoming) pointsout,paceDevitt (1996, pp. 33–6), such a view seems committed to the possibilityof a priori knowledge. I’ll touch on this issue lightly in §III below.9 Devitt (1996) writes:

We need to describe a process for justifying a belief that does not give experiencethe [causal] role indicated earlier and that we have some reason for thinking isactual. We need some idea of whata priori knowledgeis, not just what it isnot.(1996, pp. 50–1)

I find this a little bewildering. In my earlier paper, precisely what I took myself tobe doing was sketching at least the possibility of a positive naturalistic account ofa priori knowledge. Perhaps what I write here will make the positive character ofmy proposal clearer.10 In support of his interpretation, Devitt has called my attention to Quine’s useof the term to signal “the recognition that it is within science itself, and not insome prior philosophy, that reality is to be identified and described” (Quine, 1981,p. 21), as well as the “abandonment of the goal of a first philosophy. It sees naturalscience as an inquiry into reality, fallible and corrigible but not answerable to anysuperscientific tribunal, and not in need of any justification beyond observationand the hypothetico-deductive method” (Quine, 1981, p. 72). Depending uponwhat’s included in the “hypothetical-deductive method,” however, this secondsuggestion raises a quite different issue of whether empirical science as a wholecan be justified by some means external to it. Although this has been the locus ofmuch of the discussion of “naturalized epistemology” (see e.g. Kornblith, 1985),

42 GEORGES REY

esp. his introduction and contribution, and that of Stroud), this is not an issue inthe present paper. One could believe in thea priori without supposing it can curewooden legs.11 One complication: since I think it is an empirical question whether we haveanya priori knowledge at all, it becomes an empirical question for me whetherwe have anya priori knowledge of epistemology, itself. On the one hand, I don’twant to insista priori that wedo– here I take myself to agree with Quine – but onthe other I don’t want to insist that wedon’t; in which case, one then could be ledby implementing a naturalized epistemology ultimately to abandon it. It wouldn’tbe the first time one kicked away a ladder after climbing up it (a metaphor towhich I’ll return in my conclusion).12 Joseph Levine expressed a similar view at the Maryland conference. I amgrateful him and to Brian Loar for discussion of this issue, although I gatherneither of them is inclined to endorse unequivocally the uses to which I am puttingit.13 I put aside as irrelevant to our present purposes familiar problems about macro-causation, and the “overdetermination” of psychological states by mental andlogical, in addition to the usual physical properties.14 For a defense of this understanding ofceteris paribusclauses see Pietroski andRey (1995).15 I would have thought that this strategy would find a receptive ear in someone,like Devitt, who eschews “Cartesianism,” and proclaims from the start, “Meta-physics first!” (1996, p. 6).16 I don’t mean to suggest that the strategy I’m proposing is unique; but it wouldappear certainly to be compatible with Devitt’s (1996, ch. 3) own semantic mole-cularism.17 Along the lines of many other recent writers: e.g. Bach (1987), Recanati (1993)(who credits both Grice and Perry), and Devitt (1996) himself.18 Peacocke (1996), in reply to my complaints that his “primitive compulsions”are also too superficial, claims that they need to be so, in order for them to play therole of sanctioning certain explicit reasonings. However, in Peacocke (forthcom-ing) he stresses the role of “implicit conceptions,” or definitional representationsof a concept that may not be consciously available to the user of that concept.

REFERENCES

Bach, K. (1987):Thought and Reference, Oxford, UK: Oxford University Press.Bealer, G. (1982): ‘The Philosophical Limits of Scientific Essentialism’, in J.

Tomberlin (ed.),Philosophical Perspectives I, Metaphysics, 1987, Atascadero:Ridgeview.

Carroll, L. (1895/1995): ‘What the Tortoise Said to Achilles’,Mind 104 (#416):691–693 (originally published 1895).

Devitt, M. (1996):Coming to Our Senses, Cambridge, UK: Cambridge UniversityPress.


Dretske, F. (1971): ‘Conclusive Reason’,Australasian Journal of Philosophy49:1–22.

Field, H. (1996): ‘TheA Prioricity of Logic’, Proceedings of the AristotelianSociety96: 359–379.

Fodor, J. and LePore, E. (1991):Holism: a Shopper’s Guide, Oxford: Blackwell.Gleitman, H. (1995):Psychology, New York: W.W. Norton & Co., 4th ed.Goldman, A. (1967): ‘A Causal Theory of Knowledge’,Journal of Philosophy64.Kornblith, H. (1985):Naturalizing Epistemology, Cambridge: MIT Press.Levine, J. (1993): ‘Intentional Chemistry’,Holism: A Consumer Update, Grazer

Philosophische Studien46: 103–134.Nozick, R. (1981):Philosophical Explanations, Cambridge, MA: Harvard Uni-

versity Press.Peacocke, C. (1992):A Study of Concepts, Cambridge, MA: MIT Press.Peacocke, C. (1996): ‘Can Possession Conditions Individuate Concepts?’,Philos-

ophy and Phenomenological ResearchLVI (2): 433–460.Peacocke, C. (forthcoming): ‘Implicit Conceptions’.Pietroski, P. and Rey, G. (1995): ‘When Other Things Aren’t Equal: Saving

Ceteris Paribus’,British Journal for the Philosophy of Science46: 81–110.Quine, W. (1953): ‘Two Dogmas of Empiricism’,From a Logical Point of View

and Other Essays, New York: Harper and Row.Quine, W. (1954/1976): ‘Carnap and Logical Truth’,Ways of Paradox, 2nd ed.,

Cambridge: Harvard University Press, pp. 107–132.Quine, W. (1955/1976): ‘Posits and Reality’,Ways of Paradox, 2nd ed., Cam-

bridge: Harvard University Press, pp. 246–254.Quine, W. (1981):Theories and Things, Cambridge: Harvard University Press.Quine, W. (1986): ‘Reply to Vullemin’, in L. Hahn and P. Schilpp (eds.),The

Philosophy of W.V. Quine, LaSalle, IL: Open Court.Quine, W. and Ullian, J. (1970/78):Web of Belief, New York: Random House.Recanati, F. (1993):Direct Reference: From Language to Thought, Oxford:

Blackwell’s.Rey, G. (1993): ‘The Unavailability of What We Mean I: a Reply to Quine and

Fodor and LePore’,Grazer Philosopher Studien46: 61–101.Rey, G. (1996): ‘Resisting Primitive Compulsions’,Philosophy and Phenomeno-

logical Research, LVI (2): 419–424.Rey, G. (1997):Contemporary Philosophy of Mind: a Contentiously Classical

Approach, Oxford: Blackwell’s.

University of MarylandCollege Park, MD20742U.S.A.

a naturalistic a priori

Documents