The A Priori Rules of Rationality Author(s): Ralph Wedgwood Source: Philosophy and Phenomenological Research, Vol. 59, No. 1, (Mar., 1999), pp. 113-131 Published by: International Phenomenological Society Stable URL: http://www.jstor.org/stable/2653460 Accessed: 28/04/2008 16:39 Your use of the JSTOR archive indicates your acceptance of JSTOR's Terms and Conditions of Use, available at http://www.jstor.org/page/info/about/policies/terms.jsp. JSTOR's Terms and Conditions of Use provides, in part, that unless you have obtained prior permission, you may not download an entire issue of a journal or multiple copies of articles, and you may use content in the JSTOR archive only for your personal, non-commercial use. Please contact the publisher regarding any further use of this work. Publisher contact information may be obtained at http://www.jstor.org/action/showPublisher?publisherCode=ips. Each copy of any part of a JSTOR transmission must contain the same copyright notice that appears on the screen or printed page of such transmission.
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Philosophy and Phenomenological Research Vol. LIX, No. 1, March 1999
The A PrioriRules of Rationality RALPH WEDGWOOD
Massachusetts Institute of Technology
Both these ideas are intuitively plausible: rationalityhas an external aim, such as forming a true belief or good decision; and the rationality of a belief or decision is determined purely by facts about the thinker's internal mental states. Unlike earlier conceptions, the conception of rationality presented here explains why these ideas are both true. Rational beliefs and decisions, it is argued, are those that are formed through the thinker's following 'rules of rationality'. Some rules count as rules of rationality because it is rational to believe-through following other rules-that those rules are reliable. But there must also be certainbasic rules, which are a priori, or 'built into' our basic cognitive capacities. That these rules are a priori is a purely internalmatter;and in following these rules the thinker has done all that could reasonably be expected to achieve the external aim of forming a true belief or good decision.
What is it for a belief or a decision to be rational?Two ideas often spring to mind when one tries to answer this question; intuitively plausible though these ideas are, however, it is not easy to explain how they can both be true. On the one hand, it seems that rationalityis just a matterof some sort of internaljustificationor coherence:one's beliefs should supporteach other, or at least not undermineeach other, and they should be supportedby what one seems to perceive or remember;likewise, one's decisions should be supported by one's beliefs, intentions, and desires. But nothing more is required for rationality.In particular,facts about the externalworld that one knows nothing aboutmake no difference to whetheror not one's beliefs or decisions are rational.Whetheror not one's belief or decision is rationalcannotbe a matter of sheer luck. This point seems to imply an internalist conception of rationality, accordingto which the rationalityof a belief or decision is determined solely by the contents of the thinker's mind, and not by any facts about the external world that could vary while the contents of the thinker's mind remainedunchanged.If rationalityessentially involves following certainrules of rationality,then which rules one should follow, if one's beliefs and decisions are to be rational, must also be determined by the contents of one's mind alone. On the other hand, it seems (to put it roughly and intuitively) that rationality has a certain purpose. We do not just follow rules of rationality because we have a certain fetish for following those rules. We follow these THE A PRIORIRULES OF RATIONALITY I 13
rules, in forming and maintaininga belief or a decision, in orderto achieve a certain aim: specifically, in orderto ensure that our belief is true, or that our decision is a good one. The aim that we pursuein forming and maintaininga belief or a decision seems typically an externalaim: whetheror not a belief is true, or a decision a good decision, is rarelydeterminedsolely by the contents of the thinker'smind. This is highly plausible in the case of true beliefs, and it seems to me equally plausible in the case of good decisions too: my decision to accept a job offer is a good decision if and only if accepting the job offer really is a good thing for me to do, and that does not depend solely on the contents of my mind. So the ultimate purpose of following rules of rationalityseems to be to achieve these externalaims. Intuitively plausible though these two ideas are, no theory of rationality developed so far has adequatelyexplainedwhy both ideas are true.According to some theories, for example, whethera rule or principlecounts as a genuine rule of rationalitydepends on whetherfollowing the rule really is conducive to the relevantexternalaims, such as forming true beliefs or good decisions.' These theories have no problem in explaining why our basic purpose in following rules of rationality is to achieve these external aims; but they are committed to denying the internalistintuition,that whethera rule counts as a genuine rule of rationality depends purely on the contents of the thinker's mind-not on facts about the external world that could vary while the contents of the thinker's mind remainedunchanged. The theories that accept the internalistintuition, on the other hand, have trouble explaining why we should follow their proposedrules of rationality, if we are seriously pursuingthese external aims. For example, Gilbert Harman arguesthatour reasonedrevision of beliefs should be governedby a fundamentalprinciple requiringconservatismand coherence: we should always make the smallest possible change to our beliefs that is compatible with optimizing coherence.2Offhand,however, it is far from clear why we should follow this rule if we are seriously pursuingthe truth.Conservatismmay be a good way to pursue peace of mind, by avoiding radical changes in one's beliefs; and optimizing coherence may be a good way to create aesthetically pleasing patternsamong one's beliefs. But why should we follow this rule if our primaryaim is truth?3
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See, for example, Alvin Goldman, Epistemology and Cognition (Cambridge, Massachusetts: Harvard University Press, 1986), and Robert Nozick, The Nature of Rationality (Princeton,New Jersey:PrincetonUniversity Press, 1993). See Harman,Change in View (Cambridge,Massachusetts:MIT Press, 1986), p. 32. The same question can be raised about other internalisttheories of rationality.For example, R. M. Chisholm gives a series of rules that define when a belief seems intuitively 'evident' to us; see Theory of Knowledge, 2nd edition (Englewood Cliffs, New Jersey: Prentice-Hall, 1977), chapters 1-4. But why should we believe what seems intuitively evident to us if our primarygoal is believing the truth?
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If we accept internalism,it would not help to add here that following these rules actually does typically lead to truth,since that is a fact about the external world that could vary while the contents of the thinker's mind remained unchanged;and accordingto internalismwhat makes a rule a genuine rule of rationalitymust be some fact concerning the contents of the thinker's mind alone.4 It would not be enough just to add that the thinkerbelieves that following these rules typically leads to truth,since a thinkermight believe this about some perfectly crazy rules, which it would make no sense to follow if one is seriously pursuingthe truth.And it would also not help to add that the thinkerrationally believes that following these rules typically leads to truth, since what we are trying to understandis precisely when it is rational for a thinker who is seriously pursuing the truthto hold such a belief. So simply stating that this belief is rational would be circular: it would be assuming what we are trying to explain.5 It is hard to see then how a theory of rationality can explain why both these intuitions are true. Moreover, there is anotherproblem with internalist theories that seems to require a satisfactory solution to this puzzle. It has provedextremelyhardfor internalistconceptionsof rationalityto be anything more than ad hoc assortmentsof rules and principles,with no unifying structure or rationale. The fundamentalpurpose of rationality-holding a true belief, making a good decision, and so on-should be capable of providing this unifying rationale;but internalistshave so far failed to explain how it does so. In this paper, I offer an explanation of how it is possible for rationality both to be a matterof what happensinside the thinker'smind, and to involve the pursuit of external aims, such as true beliefs and good decisions. This explanation points the way to an internalistconception of rationalitythat is not just an ad hoc assortmentof principles, but has an intelligible unifying rationale.
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Many philosophershave thoughtthat it would help to adopt some form of anti-realismor the coherence theory of truth.But it is doubtful whether it does help. This is because, on any plausible version of these views, truthis still an externalistproperty,in the sense that the truthvalue of a belief is not determinedsolely by the thinker'sactual mental states. So the problem arises just as much for these views of truthas for realism, or the correspondence theory of truth. Some philosophersexplain why some rules count as rules of rationalityby arguingthat it is rational for us to believe-by following other rules-that the former rules typically lead to truth. But this strategy cannot be employed for all rules of rationality,on pain of an obvious infinite regress. This is the problemwith the argumentthat Laurence BonJour offers in The Structure of Empirical Knowledge (Cambridge, Massachusetts: Harvard University Press, 1985), pp. 157-88. John L. Pollock raises this problem for all forms of internalism other than his own, in Contemporary Theories of Knowledge (Totowa, New Jersey: Rowman & Littlefield, 1986), pp. 93-96. Ernest Sosa argues convincingly that the problem arises for Pollock's views as well, in Knowledge in Perspective (Cambridge: Cambridge University Press, 1991), pp. 127-30.
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In the first two sections, I suggest an account of what it is to follow rules; a rational belief or decision, I propose, is one that is based on the thinker's following rules of rationality.The central question then becomes: Which, out of all the myriad rules that could be imagined, are the genuine rules of rationality?I argue that answers to this question are subject to the following condition of adequacy: genuine rules of rationalitymust be such that following them is a way for the thinkerto be doing all that can reasonably be expected in orderto achieve the requiredexternalaims-to ensurethat her belief is true or thather decision is a good one. In the third and fourth sections, I propose an internalist account of the rules of rationalitythatmeets this condition of adequacy.Rules of rationality, I argue,are of two kinds. First,there are derivedrules:these are rules which it is rationalfor one to follow solely because it is rationalfor one to believe, as a result of following other rules, that the rules in question are reliable-that is, that they are conducive to the relevant external aims (such as holding a true belief or making a good decision). Second, there are the basic or underivedrules: these are rules which it is rationalfor all rationalbeings to follow, so long as they are capable of doing so. These basic rules of rationality are a priori: their status as genuine rules of rationality does not derive from any empirical evidence that the thinkerhas at her disposal, but purely from the structureof the thinker'scognitive capacitiesthemselves. I propose that these basic a priori rules are the rules that are in a certain way indispensable for all rationalbeings who possess the relevant cognitive capacities. This proposal, I argue, can explain how any thinkerwho follows these basic rules would be genuinely pursuingthe requiredexternalaims, and at the same time doing no less thancan reasonablybe expected of her in order to achieve those aims: that is, it can explain why these basic a priorirules are genuine rules of rationality. 1. Two Features of Rationality: Internalism, and the Pursuit of an External Aim What sorts of things can be rationalor irrational?In this paper, I shall focus exclusively on rationalmental states. But not all mental states can be rational or irrational.There are some types of mental state that do not result from reasoning, and cannot be based on reasons. Experiences, for example, are mental states that we are simply saddled with; they are not based on reasons and do not arise from reasoning. (For example, the stick half immersed in water still looks bent even if you know that it is straight.) Other types of mental states can result from reasoning,or be based on reasons:the paradigm cases of these types of mental state arejudgments,beliefs, and inferences, on the one hand, and intentions and decisions, on the other. It is primarilymental states of this latter kind that can be assessed as rational or irrational.In what follows, I shall refer to mental states of this latterkind as 'attitudes'. 116
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Besides assessing attitudes as rational or irrational, we can also assess them as correct or incorrect,appropriateor inappropriate.If one believes that p, then this belief is appropriateif and only if what one believes is true-that is, if and only if it is truethatp. If one makes a certaininference, or accepts a certain argument,then this inference is appropriateif and only if the argument is truth-preserving.If one decides to 4, then one's decision is appropriate if and only if this is a good decision-that is, if and only if M-ingis a good thing for one to do. A belief is faulty or defective unless it is true; an inference is faulty or defective unless it is truth-preserving;a decision is faulty or defective unless it is a good decision. In general, it is one of the thinker's aims, in forming an attitude, to ensure that the attitudeis appropriatein this sense. For example, one of the aims that the thinkeris pursuingin forming the belief that p is this: that he should form this belief only if it is true thatp.7 Note that I am not claiming that forming a particularbelief-the belief that p, say-is itself an intentional action. Even if forming a belief cannot be an intentional action, the belief will often be based on some sort of reasoning or consideration of reasons; and this reasoningmay well be an intentionalactivity, and if it is, it will be guided by the intentionof forming a true belief on the question. Even when reasoning is not an intentional activity, it typically proceeds just as though it were the intentionalpursuitof the goal of reaching a true belief on the question. In this way, we appearto be active or spontaneouswith respect to our attitudes,while we are merely passive or receptive with respect to our experiences or othermental states. Attitudesare states of the kinds that result from reasoning; and reasoning involves actively aiming to ensure that the resultingattitudesarecorrector appropriate.' In general, rationalityseems to be a matterof the thinker's doing all that can reasonablybe expected of someone in her circumstancesto ensurethather attitudeis appropriate,or achieves its fundamentalaim. A belief is rationalif and only if the thinkerhas done all that can reasonablybe expected to ensure that the belief in question is true. A decision is rational if and only if the agent has done all that can reasonablybe expected to ensure that the decision is a good one. This is not intended as an analysis of rationality (as such it would be unsatisfyingly circular); something closer to an analysis will be developed later. It is intended as an intuitive formulation of an important truthaboutrationality.In effect, we may regardit as a condition of adequacy Compare Christopher Peacocke's remarks about judgment in Thoughts: An Essay on Content (Oxford: Blackwell, 1986), p. 46. Note that I am not saying that our thinking ought to be regulated by the general epistemic goal of maximizing the ratio of true to false beliefs. One has a separategoal for each of one's beliefs: one of the goals that one is pursuing,in holding any given belief, is not to hold that belief unless it is true. (One may of course also be pursuingother goals as well.) Compare Philip Pettit, The CommonMind (New York: Oxford University Press, 1993), chapter 2. THE A PRIORIRULES OF RATIONALITY 1 17
that any analysis of rationalitymust meet: any adequateanalysis, of what it is for an attitudeto be rational,must imply that in forming and maintaining a rationalbelief or decision the thinkerhas done all that could reasonablybe expected to ensurethather belief is true or thather decision is a good one. So rationalityrequiresthatthe thinkershould do all thatcan be reasonably expected in order to ensure that her attitude is appropriate,or achieves its essential aim. It does not requirethather attitudeactuallybe appropriate.She may just be unlucky. She does all that could reasonablybe expected to ensure that her belief is true, but in fact the belief is not true; this need not prevent her belief from being perfectly rational.Whetheror not an attitudeis rational does not depend on luck in this way. Whether or not a thinker has done all thatcan reasonablybe expected dependson how she has respondedto the evidence that was availableto her. It does not depend on facts aboutthe external world that she knew nothing about at the time. Whetheror not an attitudeis appropriateis usually a fact aboutthe externalworld. Whetheror not an attitude is rationaldepends on its relationto the thinker'spoint of view. Imagine two thinkers who go through exactly the same processes of reasoning, on the basis of all the same experiences, intuitions, desires, and apparentmemories, and form all the same attitudes.Then, it is plausible to say, exactly the same attitudesare rationalin each case, even if one thinkeris bedevilled by an evil demon who ensures that many of her attitudes are inappropriate,while the other thinkeris not. This seems to imply that rationality is an internalist standard;that is, the rationalityof an attitudeis determined solely by the contents of the thinker'smind-not by any furtherfacts that could vary while the contents of the thinker'smind remain unchanged.' More precisely, the rationality of an attitude is determined by facts about what mental states the thinker has and lacks, and by these mental states' causal and logical relationsto each other;as I shall put it, it is determinedby 'facts about the thinker'smental states'. When I speak of 'mentalstates' here, I am not including states such as knowing, or seeing, or remembering,that are necessarily correct or appropriate:I am including only types of mental state that can sometimes be incorrector inappropriate,such as beliefs, experiences, apparentmemories,decisions, and so on. Several externalists have admitted that there must be some sense of 'justified' in which two thinkers who have exactly similar mental lives have equally justified beliefs, even if one of them is bedevilled by an evil demon and the other is not. See, for example, Alvin Goldman, Epistemology and Cognition, pp. 107-13, and Ernest Sosa, Knowledge in Perspective, pp. 132-45. This is bound to be an internalistsense of 'justified', since it makes the justifiedness of a belief superveneon the contents of the thinker's mind alone. Indeed, it seems plausible that any sense of 'rationality' or 'justification' in which a belief is rationaljust in case it is 'epistemicallyblameless' must be an internalistsense in this way; and my topic in this paperis rationalityin this sense. Some of these externalistsargue that this internalist sense of 'justified' is in some way less fundamental than, or derivative from, an externalist sense of the term. I cannot assess these arguments here, although I am unconvinced. 118
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It is certainly controversialto claim that these considerations show that rationality is an internalist standardin this sense. Many more arguments could be offered on both sides.10But I shall not say any more to defend the internalist conception of rationality here. For the rest of this paper, I shall simply assume that rationality is an internalist standard. Even those who doubt whetherrationalityis an internaliststandardshould be interestedto see how an internalistconception of rationalitycan be reconciled with the idea that rationalityhas an external aim, such as having a true belief or making a good decision. Rationality as I shall understand it then has the following two basic features: it is an internalist standard,depending solely on facts about the thinker's mental states, and it is a matter of the thinker's doing all that can reasonablybe expected to ensure that her belief is true, that her decision is a good decision, and, in general, that her attitude is appropriaterather than faulty or defective. 2. The Basis for Attitudes: Following Rules It seems that the rationalityof an attitudedepends on the way in which the attitudeis formed and maintained.More specifically, it depends on the basis on which the attitudeis held. The basis of an attitudeconsists of certainfacts about the thinker's mental states that explain the attitude's being currently held: they may include, for example, the thoughtsand reflectionsthat led the thinker to adopt the attitude;but they may also include other facts, such as the continuedabsence of defeatingor countervailingevidence, which account for the attitude'sbeing retained. It may be plausible that not all of the facts about the thinker's mental states that explain an attitude'sbeing held are partof the basis of the attitude. If one can no longer rememberhow one originallycame to hold a certainattitude, then perhaps we should not regard such long-forgotten facts as still forming part of the basis of the attitude.Maybe we should say, for example, that an attitudeis based on certainfacts aboutthe thinker's mental states only if those facts are all currently accessible for the thinker to think about or reflect upon. In this paper,however, I shall remainneutralabout whether we should impose this restriction.The central point is just that the basis of an attitudeconsists of certainfacts about the thinker'smental states that explain the attitude'snow being held. 1(
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One powerful argumentfor internalism is given in Pollock, ContemnporalyTheories of Knowledge,pp. 133-49. Hence an account of what counts as a rationalbasis for an attitudewill imply an account, not only of when it is rational to form the attitude, but also of when one is rationally required to give up the attitude-assuming that one must give up an attitude as soon as one no longer has any rationalbasis for retainingit. Compare Alan Millar, Reasons and Experience (Oxford: ClarendonPress, 1991), chapter2.
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If an attitudeis rational,and if the attitudeis based at least in parton other attitudes, then those other attitudes must themselves also be rational. For example, if my belief thatp is based on my beliefs that q and that r, then my belief that p is rational only if my beliefs that q and that r are also rational. The rationalityof these antecedentattitudeswill likewise depend on the facts about the thinker's mental states on which they are based. Hence, if a rational attitudeis based on any furtherattitudes,then the basis for that rationalattitude must include the bases for all those furtherattitudes.If my rationalbelief that p is based on my beliefs that q and that r, then the basis for my belief that p must include the bases for my beliefs that q and that r. In addition, of course, each of these attitudesmust be held on the right kind of basis: viz., a basis on which it is rational to hold the attitudein question.But what kind of basis is that? One answer to this question starts from the assumption that the thinker forms and maintainsattitudesby following rules. We can analyse the way in which an attitudeis based on certain facts about the thinker's mental states into a (partiallyordered)set of steps, such that there is exactly one step for each attitudeinvolved, revealing what it is that that attitudeis based on. Suppose that my belief that p is based on my beliefs that q and that r, and my belief that q is based on an intuition, while my belief that r is based on an experience. Then the way my belief thatp is based on facts about my mental states involves three attitudes (my beliefs that p, that q, and that r); and accordingly it can be analysed into three steps-the step leading from the intuition to the belief that q, the step from the experience to the belief that r, and the step from the beliefs thatq and that r to the belief thatp. Now a rule is a general form that such a step may have. In general, we may suppose that a rule has two elements: a certain set of mental conditions that one might be in, and a certaintype of change of attitude,which would be made on the basis of those mental conditions by means of one step of that general form. We may call the former conditions the 'input conditions' for the rule, and the latterthe 'output'of the rule. We should allow the outputof a rule to take various forms: not just forming or continuingto hold a certain attitude,but also rejectingor refrainingfrom holding a certainattitude. For example, consider the following rule: If any question arises about the colour of a visually presentedobject, and if the object is presentedin a region of the visual field that has a certain distinctive phenomenalcharacter,and it would be rationalto assume thatone's circumstancesare favourableand actually typical, then judging, on this basis, that the object is green, would be a step that is an instance of the rule in question. Or consider the following rule of logical inference: If an argumentoccurs to one, and that argumentis recognizably an instance of modus ponens-that is, for some propositions A and B, the argument'spremisses are A and 'If A, then B', and its conclusion is B, then accepting the argumentwould be a step that is an instance of this 120
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rule of logical inference.'2 Or, finally, consider the following rule of practical reasoning:If it would be irrationalfor one to believe that one has considered enough alternativeoptions, or if one of the alternativeoptions that one has considered is clearly better,all things considered,than a particularoption, 0ing, then refraining,on this basis, from deciding to 4, would be a step that is an instanceof this rule of practicalreasoning. To follow a rule is more than merely to conform to it; it is certainly not enough if one conforms to the rule by pure chance, for example. This difference, between mere conformity to a rule and genuine rule following, raises large philosophical questions, which I cannot address adequately here. Roughly, however, I propose that to follow a rule is to have a change of attitude, on the basis of a certain step, precisely because the step is an instance of the rule-that is, because it has the generalform in question. In that sense, the thinker's thinking is regulated or guided by these rules: the thinker is exercising her competenceor masteryof the rule. At all events, whateverexactly turnsout to be the best account of rule following, we may assume that it is possible to follow a rule without consciously thinking about the rule, and without having any ability to formulate the rule. The rule is what actually guides or regulates our going on in the way we do; it need not be immediately accessible to consciousness. For example, one may follow this rule for judging objects to be green, without possessing the concept of the phenomenalcharacterof regions of the visual field, or even the concept of a rule, let alone having consciously formulated the rule. Some of the rules that one might follow will be rules of rationality.There are two main ways in which a rule can be a rule of rationality.Some rules are rational requirements, or rules that one rationally ought always to conform to: whenever one is in the input conditions of the rule, then one ought to follow the rule and make the relevantchange in one's attitudes.The rules that I have surveyed so far are plausibly rules of this kind. It is irrationalto consider an argumentthat is recognizably an instance of modus ponens, and not accept the argument;and it is irrationalto decide to pif it would be irrational to believe that one has consideredenough alternatives,or if one has considered some other alternativethat is clearly preferableto 0-ing. But there are other rules which are merely rational permissions rather than rational requirements.If one is not required,by any rule of rationality,to refrainfrom deciding to 0, then one may decide to 0; and in so doing one would be following a rule of rationality.
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Accepting an argument is not the same as accepting the argument's conclusion: it is appropriateto accept any valid argument,even if both the premisses and the conclusion of the argumentare clearly false. THEA PRIORI RULESOFRATIONALITY121
This notion of rules of rationality allows us to define what it is for an attitudeto be rational,in the following way. Roughly, an attitudeis rational if and only if each step, in the way in which the attitude is based on facts about the thinker's mental states, consists of the thinker's following some genuine rule of rationality. But which, of all the myriad possible rules that could be imagined, are the genuine rules of rationality?Which of these rules is it rational to follow in forming and maintainingone's beliefs and intentions? 3. Aiming at Reliability, and A Priori Rules I have arguedthatrationalityinvolves the thinker'sdoing all that can reasonably be expected to ensure that her belief is true, and that her decision is a good decision-in general, that her attitudeis appropriate.If rationalityis a matterof following rules, then a genuine rule of rationalitymust be such that the thinker's following the rule is a way for her to do all that can reasonably be expected to ensure that the attitudeformed by following the rule is appropriate-that the belief formed by following the rule is true, or the decision formed by following the rule a good one. How can a humanthinkerset about ensuringthat her belief or decision is appropriate?Only, it seems, by trying to ensure that the belief or decision is formed and maintained in a reliable way-that is, in such a way that it is unlikely, or could not easily happen, that she would form and maintain a belief in that way unless it were true, or that she would make a decision in that way unless the decision were a good one."3 Note that I am not saying thatrationalityrequiresactualreliability:on the contrary,I am assuming that rationalityis a purely internalistcondition, so that actual reliability, which is an externalist condition, is not requiredfor rationality. I am claiming that rationalityinvolves trying to form and maintain one's attitudesin a reliable way. In effect, activities of rationalattitudeformation and attitude-maintenanceaim at reliability,in much the same way that beliefs aim at the truth and decisions at being good decisions.14A rule can count as a genuine rule of rationality for a given thinker, then, only if following this rule is a way for the thinkerto be doing all that can reasonably be expected to form and maintainher attitudesin a reliablefashion. What does this tell us about which rules count as genuine rules of rationality? Well, there is an obvious sense in which rules themselves can be 13 14
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Compare Bernard Williams, Descartes: The Project of Pure Enquiry (Harmondsworth: PenguinBooks, 1979), pp. 37-47. Reliabilists, like Alvin Goldman,also claim that the concept of reliability is a crucial concept for epistemology, and more generally for the study of rationalityas such. Although they were right to emphasize the importanceof the concept of reliability, they misunderstood the role that it should play: rationalityinvolves aiming at reliability, not necessarily achieving it.
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called reliable or unreliable.We may call a set of rules a reliable set if, and only if, any attitudeformed purely by following rules that belong to that set will be formed in a reliable way; then we may call a particularrule a reliable rule if, and only if, adding thatrule to a reliable set of rules will always yield a reliable set of rules. For example, the rule of presumingthat one's experience is veridical, in the absence of special evidence to the contrary,will be a fairly reliable rule, if one is not a victim of any Cartesianevil demon. A rule that involves accepting instances of modus ponens is reliable in all possible circumstances:if one's beliefs are already reliably formed, then adding this rule cannotpossibly lead to new beliefs that are not reliably formed. Assuming internalism, however, a rule can be reliable without being a rule that it would be rational for one to follow: for example, the rule of believing whatever is asserted in a Papal encyclical might be wonderfully reliable, but it would certainlynot be a rationalrule for me to follow. Moreover, a rule could be a genuine rule of rationality without being a reliable rule. For example, it is rational to follow the rule of presuming that one's experienceis veridical,in the absenceof special evidence to the contrary,even if, thanksto an evil demon, this is an unreliablerule for one to follow. It seems that some rules are actuallyguaranteedto be reliable by the identity of the concepts and attitudes involved. For example, the rules that involve accepting instances of modus ponens, or refusing to accept both a propositionand its negation,are guaranteedto be reliable, purely by the identity of the concepts if and not. (Such rules might be called analytic rules.) But, as we have seen, rules of rationalityare not always reliable. It is rational to follow the rule of presuming one's experience to be veridical, in the absence of special evidence to the contrary,even if an evil demon has ensured that it is an unreliablerule for you to follow; this rule is certainly not guaranteed to be reliable. (As we might put it, it seems to be a synthetic rule of rationality.)So not all rules of rationalityare guaranteedto be reliable in this way. Moreover,the converse also holds: not all rules that are guaranteedto be reliable in this way are genuine rules of rationality.For example, the fact that an inferencefrom Peano's Axioms to Fermat'sLast Theoremis guaranteedto be reliable, by the identity of the concepts involved, does not make it rational for you to make the inferenceif you have no idea thatthe inferenceis valid. Nonetheless, as I have argued, a rule counts as a rule of rationality only because following the rule is a way for the thinker to be doing all that can reasonably be expected to form her attitudes in a reliable fashion. If it is rationalfor a thinkerto follow a given rule, then it must also be rational for her to accept that 'thinkingin that sort of way' (what we theorists might call following the rule) is reliable, if she considered the question. This helps to explain why it would be irrationalfor me to follow the rules of believing whateveris assertedin a Papal encyclical, or of acceptingthe inference from Peano's Axioms to Fermat's Last Theorem: if I considered the question, it THE A PRIORIRULES OF RATIONALITY
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would not be rationalfor me to accept that these are reliable rules for me to follow. Perhaps,then, following a given rule could be a way for a thinkerto try to form her attitudesin a reliable fashion because the thinkerhas some evidence of the rule's reliability. Perhaps this is what makes it rational for a thinker to follow the rule-the fact that the thinker has some positive evidence of the rule's reliability. There certainly seem to be rules of this kind. For example, it is rational for me to form beliefs about the time of day by looking at clocks and watches: if it is rational for me to believe that both hands of a clock are pointing straightup, then (if I have no positive evidence that the clock is not telling the right time) I may believe that it is twelve o'clock, by means of following a familiar rule. I also have some evidence that clocks are generally reliable indicatorsof the time of day. Moreover, it seems that it is only because I have such evidence of the rule's reliabilitythat it is rationalfor me to follow the rule. There is a problemhowever with supposingthat all rules of rationalityare of this kind. What can 'having evidence of the rule's reliability' mean here, other than: being in some mental conditions on the basis of which it would be rational to believe that the rule is reliable? Suppose that that is what it means, and that one has evidence of some rule's reliability. Then one is in some mental conditions on the basis of which it is rationalto believe that the rule is reliable. Ever since section 2, I have been assuming that, if a set of mental conditions counts as a rationalbasis for a belief, that must be because there is some genuine rule of rationalitywhich one could follow in holding the belief on that basis. All such rational connections, without exception, depend on rules of rationality.Since one has a rationalbasis for believing the rule reliable, there must be some rule of rationalitywhich one could follow in holding this belief on that basis. This latterrule must already be a rule of rationality-that is, independentlyof one's having the evidence in question (it is this rule that makes those mental conditions count as evidence in the first place). Hence it cannot always be the case that the only thing that makes a rule a genuine rule of rationality is one's having positive evidence of the rule's reliability. So not every rule of rationalitycounts as such purely because the thinker has positive evidence of the rule's reliability. This appears to support the conclusion that there are certainbasic rules, which are genuine rules of rationality for all rational beings who are capable of following them, independently of any empirical evidence that they may have concerning the rules' reliability. This conclusion might seem to be foundationalistin spirit:assuming that every rule of rationalitycounts as such purely because the thinker has evidence of the rule's reliability sets off a regress; so instead we must postulate basic rules, whose status as genuine rules of rationalityis independentof any 124
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evidence concerningtheir reliability.It is importantto see that this is not traditional foundationalism, however; it is perfectly compatible with most forms of coherentism.Traditionalforms of coherentism actually postulate a basic, fundamentalrule of rational belief-specifically, a rule that requires that one always revise one's beliefs in a way that optimizes coherence. So, in this sense at least, my conclusion is not foundationalist: it is compatible with rejecting the idea of foundationalor basic beliefs-although, of course, it is not compatiblewith rejectingthe idea of basic rules. Perhaps, however, there is an alternativethat I have overlooked. Traditional 'belief coherentism'actuallypostulatesa basic rule of rationality-the rule that requires coherence-which applies to all rational beings independently of any empiricalevidence regardingthe rule's reliability. But perhaps there could be anotherform of coherentism, 'rule coherentism', accordingto which not all rules of rationalitycount as such purely because one has evidence of their reliability, but, equally, no rule counts as a rule of rationality independently of evidence concerning its reliability: instead, every rule is capableof sufferingrationallywarrantedrejectionin the presence of evidence that it is unreliable. Many philosophers are tempted by the view that no rule is immune to being underminedby evidence that it is unreliable.Presumably,anyone who holds this view will also hold that one should rationallyreject and refuse to follow a rule whenever one has evidence showing that the rule is unreliable. In that case, however, this position is incoherent, since it is committed to postulating some rules that are immune to rational rejection. For example, this position entails the following: one should refuse to form beliefs on the basis of experienceif one has evidence showing that one's experienceis unreliable. But this is itself a rule! So this position must accept that this rule is also capable of being rationallyrejected. Suppose that this rule is rationally rejected: the old practice of refusing to form beliefs on the basis of experience, whenever one has evidence showing one's experience to be unreliable, is now irrational.So it could now still be rationalto follow the rule of forming beliefs on the basis of experience, even if one had evidence showing that one's experience was unreliable.But that contradictsthe assumptionthat one should reject a rule whenever one has evidence showing that it is unreliable. So it is in fact incoherentto claim that all rules are capable of being rationally underminedin this way.'5
15
Indeed, all internalistaccounts of rationalityare committed to the existence of basic rules of rationality.Any account of rationalitymust make some claim about the natureof rationality in general; if it is a non-trivialinternalistaccount, this claim will imply some general restrictionson the mental conditions in which it is rational to hold certain attitudes; and these general restrictionsare in effect rules, which it will be necessarily rational for all thinkerswho are capable of doing so to follow. THE A PRIORIRULES OF RATIONALITY 125
I conclude then that there are some basic rules, which are genuine rules of rationalityfor everyone who has the capacities necessaryfor following them, regardlessof the empiricalevidence that is at their disposal. This implies that these rules are in a clear sense a priori. These rules are rationalrules to follow, not because of any empirical evidence that the thinker has at her disposal, nor because of any mental states that are only contingentlyenjoyed by thinkerswho possess the relevantcognitive capacities, but purely because of some connection between those rules and the structureof the relevant cognitive capacities: in some way, these rules are simply 'built into' the structure of those cognitive capacitiesthemselves. I am relying here on a broadly Kantianconception of the a priori. This is how Kantfirstintroducesthe centralquestionof the Critiqueof Pure Reason: But even though all our cognition begins with experience, it does not follow that it all arises out of experience. For it may well be that even our empirical cognition is composed both out of what we receive through impressions and out of what our own cognitive faculty (sensory impressions serving merely as the occasion) supplies out of itself.16
This suggests the following way of characterizingthe a priori:the a priori is what our relevantcognitive capacities "supplyout of themselves".Ourcognitive capacities supply a rule out of themselves, we may suppose, just in case anyone who has those capacities must have a mastery of the rule, or at least be in a position to acquire such mastery, simply through exercising those capacities, without relying on informationthat is not necessarily available to everyone who possesses those capacities. In the case of a basic rule of rationality, I have argued, it is rational for all thinkers who possess the relevant cognitive capacities to follow the rule. Presumably, if it is rational for a thinker to follow a rule, then she must at least be in a position to acquire a mastery of the rule (if she does not possess such mastery already).So, in the case of basic rules of rationality,all thinkerswho possess the relevant cognitive capacities must at least be in a position to acquire a mastery of those rules, regardlessof the empiricalevidence at theirdisposal. In this sense then, all the basic rules of rationality are a priori: they are rules that our cognitive capacities supply out of themselves, ratherthan rules that it is rationalfor us to follow because of additionalmental states that we have happenedto have, over and above those that are necessarily enjoyed by everyone who possesses the cognitive capacities in question. But this only makes it harderto understandhow these rules can be genuinerules of rationality, given that any rule of rationalitymust be such that following the rule is a way of genuinely trying to form and maintainone's attitudesin a reliable fashion. Why should following a priorirules, which are 'built into' our cog-
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nitive capacities, be a way of trying to pursue the truth,or of trying to form good decisions aboutwhatto do? 4. Which Are the Basic A Priori Rules? We need to be assuredthen thatthese a priorirules really are genuine rules of rationality-that is, that following these rules really is a way for the thinker to do all that can reasonablybe expected in order to form and maintain her attitudes in a reliable fashion. According to the conception that I have proposed, a priorirules are the rules that the relevantcognitive capacities supply out of themselves. But which are the relevant capacities? (Clearly, not all cognitive capacities are relevant here: my capacity to hum Mozart arias is presumablynot relevant, for example.) And how do these capacities supply the rules out of themselves-that is, how do they 'put us in a position' to acquirea masteryof the rules? First, we should note that, although all basic rules of rationality are a priori, not all a priorirules are basic: there are some a priorirules which it is rationalto follow only because one has a priorigroundsfor believing them to be reliable;these are derivative,non-basic a priorirules. For any of the basic a priori rules of rationality,the relevant cognitive capacities must supply us with a masteryof the rule in a more direct way: we can achieve such mastery without having first to follow some other rule in order to appreciatethe evidence for the rule's reliability;exercising those capacitiesdirectly supplies us with a masteryof the rule. How could cognitive capacities 'directly' supply us with a rule in this way? I propose the following. Consider a thinkerwho is exercising the relevant capacities, is in the input conditions of a rule, and considers making the change in attitude that is the output to the rule. Let us assume that no perturbingfactorsaffect the thinker'smental function:for example, she does not suffer any sudden fit of narcolepsy,but remainsmentally alert and attentive. Now suppose that it is necessarily the case, simply in virtue of her exercising the capacities in question, that the thinker will be immediately inclined to follow the rule in such circumstances. Perhaps it is sometimes possible to resist this inclination-perhaps the thinker is brow-beaten by an authority figure into a total lack of confidence in her own judgment, or perhaps her inclination is swamped by powerful countervailing emotions. But, let us suppose, any thinker who is exercising these capacities in these circumstances must at least have this immediate inclination to follow the rule. In that case, the capacities in question would supply the rule directly out of themselves; and if these are examples of the 'relevant' cognitive capacities, then this rule would be a basic a priorirule. Which then are the relevant cognitive capacities? I propose that the relevant capacities, which supply basic a priori rules out of themselves, are the capacities that we must have even to ask the questions that we are considerTHE A PRIORIRULES OF RATIONALITY
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ing. Take any rationalbeing, of finite information-processingpowers, who is capable of even asking the question, 'Is it the case thatp?' or 'Should I ? or not?' To be capable of asking this question, the thinker must have various capacities: she must possess all the concepts that occur in the question, and she must also have certainmore general capacities, such as the capacities for self-conscious reflection,and formingjudgments or decisions on the basis of reasons. A rule counts as a basic a priori rule if, and only if, it is necessary that any thinkerwho has these capacities will be immediatelyinclined to follow the rule, when she is in the input conditions of the rule, exercising those capacities, and consideringwhetherto make the change of attitudethat is the output of the rule. Establishing that a rule is a priori, then, would involve arguing that the rule is 'built into' some such cognitive capacity; and that would require a full-blown philosophical psychology of the capacity in question-a task that exceeds the scope of this paper. Here I shall only argue for conditional claims, of the form: if it is essential to possessing cognitive capacity C that one has an immediate inclination to follow rule R, then rule R is a priori. I shall give three examples. In the first two, the capacity in question is the capacity of grasping a certain concept (first the concept green, and then the concept if...); in the thirdexample, the capacity is not just graspinga certain concept, but the more general capacity for making decisions on the basis of reasons. First then, consider the rule for judging things to be green that we discussed earlier: following this rule involves judging an object to be green when it is presentedin a region of the visual field that has a certainphenomenal character,and it would not be irrationalto suppose that one's circumstances are favourableand actuallytypical. Suppose thatany thinkerswho are exercising their grasp of the concept green must be immediately inclined to follow this rule, whenever they are in the input conditions of the rule (they are having an experience of the relevant kind, and so on), and they consider whether the object is green. In that case, this rule would be a basic a priori rule. Second, consider the rule that involves accepting instances of modus ponens. Suppose that anyone who is exercising their grasp of the concept if.... must be immediately inclined to follow this rule whenever a recognizable instance of modus ponens occurs to them. Then this rule of logical inference would also be an a priorirule. Finally, considerthe rule of practical reasoningconsideredabove-the rule thatinvolves refrainingfrom decidingto 4 when it would be irrationalto believe that one has consideredenough alternatives, or when one of the alternatives that one has considered is clearly better, all things considered,than 0-ing. Suppose that anyone who is exercising their capacityfor reasoneddecision-makingmust be immediatelyinclined to follow this rule, when they are in the input conditions of the rule, and
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considering whether to ?. In that case, this rule would be an a priori rule of practicalreasoning. Different assumptionsaboutthe natureof the relevantcognitive capacities would support different accounts of the basic a priori rules of rationality. Some philosophersdoubt that there are rules built into our grasp of particular concepts, but accept that there are certain rules built into our more general capacities for the reasoned formation and revision of belief. For example, suppose that anyone exercising their capacity for reasoned belief-revision must be immediately inclined to revise their beliefs in a certain way, whenever they consider revising their beliefs in that way, and that revision would in fact optimize coherence among their beliefs. In that case, the rule that requirescoherencewould be an a priorirule of belief-revision.The framework proposed in this paper is not in competitionwith traditionalcoherentism:on the contrary,it could help to supply the necessary explanation,which coherentists have so far failed to provide, of why the coherence rule is a genuine rule of rationality. According to this proposal then, the basic a priori rules that apply to a given thinker are rules that the thinkermust be immediately inclined to follow if she is to be capable of asking herself the questions that she is actually capable of asking. The capacity for asking those questions presupposes the capacity for certain types of mental states and processes, which in turn implies this sort of masteryof the rules. But are these basic a priorirules genuine rules of rationality?In following these a priori rules, is the thinker really doing all that can be reasonably expected to form and maintainher attitudesin a reliable fashion? I shall now argue that she is. First, in following these basic a priorirules, the thinkeris aiming to form and maintainher attitudesin a reliablefashion. So long as these rules are not positively self-undermining, then, on any plausible view, these rules will themselves lead to the conclusion that they are reliable rules. Whenever one forms a belief by following a rule, the rules will also yield the conclusion that this belief is true. If one possesses adequatepowers of introspection,one is in a position to see that one has formed this belief through following the rule. If one possesses adequatememory, one will rememberearlieroccasions when one followed the rule and thereby(as one believes) formeda truebelief. But then a simple inductionleads to the conclusion that this rule is generally reliable. A parallelpoint holds for rules of practicalreasoning.Very roughly, the basic rule of practicalreasoning allows one to decide to ? when the rules for rational belief allow one to believe that M-ingis a good thing to do. So this rule is obviously reliable: adding this rule to a reliable set of rules (includingreliable rules for belief) will always yield a reliable set of rules. In this way, the belief that these rules are reliable is effectively implicit in the practiceof following the rules. THE A PRIORIRULES OF RATIONALITY
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This first point is clearly not enough, however, since it holds of many perfectly ridiculous sets of rules, as well as of the basic a priorirules that we are considering. We also need to show that in following these basic a priori rules, the thinkeris not only trying to form and maintainher beliefs in a reliable way, but is also doing all that can reasonablybe expectedof her in order to achieve this end. So what is it reasonable to expect of a thinker who is pursuingthis end? It seems to me that the only demand that it is reasonable to expect the thinkerto meet is that she minimize the possible sources of error,by restricting the numberof rules that she treatsas basic, in some principledway. Once the thinkeralreadyhas some rules which it is rationalfor her to follow, then she can use those rules to form beliefs about which furtherrules are reliable; and there can be no objection to her following those furtherrules. The only reasonabledemandconcernsthe rulesthatthe thinkertreatsas basic. It would be obviously unreasonableto demand that the thinker treat no rule as basic. For that is equivalentto demandingthat she follow no rules at all; and if all rationalattitudesare based on following rules, then it is metaphysically necessary that all rationalthinkersfollow at least some rules (for how could there be a rationalthinkerwho had no rationalattitudesat all?). So the only reasonable demand is that the thinkerrestrict herself to treating as basic some small but non-empty set of rules, which can be singled out in a way. principled,non-arbitrary It seems to me that there is no more restricted set of rules that can be singled out, in a non-arbitraryway, as rules that it makes sense for the thinkerto treatas basic, than the rules that are built into the cognitive capacities requiredin orderto ask the questions that she is capable of considering. The thinkercannotbe faultedfor having these capacities(indeed, if any of the thinker's capacities make her a rational being, these capacities are surely among them); and it is metaphysicallynecessarythat having those capacities involves being immediatelyinclined to follow these rules when the opportunity arises. The thinkerhas to startby treatingsome rules as basic; and where else should she startthan with the rules that have this sort of necessary grip on her? It would be arbitraryand unreasonableto demand that she should limit herself to any other, more restrictedset of rules. So in following these rules she is doing all that can reasonablybe expected of her, in orderto form and maintainher attitudesin a reliable way. I conclude that it is indeed rational for her to follow these basic a priorirules. In claiming that we are necessarily inclined to follow these basic rules, I am not appealing to the Humean idea that "Nature ... has determinedus to The necessity of being inclined to follow these judge as well as to breathe"."7 17
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rules is a metaphysical necessity for all thinkerscapable of asking the relevant questions, not simply a naturalnecessity for members of our biological kind. It is not that we must be excused our following these rules, as an inevitable foible of our nature.Rather, we are fully warrantedin following these rules; for in following them, we are pursuingthe aim of having a true belief, or making a good decision, in the only way available for anyone who can even ask the questionsthatwe are considering. It must be conceded that this conception of rationalityremains programmatic in a crucial respect. According to this conception, there are two kinds of rules of rationality:there are derivative, non-basic rules, which it is rational for the thinkerto follow only because it is rationalfor her to believe (by means of following other rules) that the rules in question are reliable; and there are basic rules, which it is rationalfor the thinkerto follow because it is necessary that any thinkercapable of asking the questions that the thinker is actually capable of asking will be inclined to follow the rules when the opportunityarises. I am still a long way from having shown that every rule that is plausibly a rule of rationalitybelongs to one of these two kinds. That formidabletask must be left for anotheroccasion. My chief aim here has just been to show how this conception of rules of rationalitycan resolve the tension that we noted at the outset-between the two intuitions that rationality is a purely internaliststandard,and that it has an external aim, such as holding a true belief or makinga good decision.'
Ancestors of this paperwere presentedto the Philosophy Departmentsof the Universities of Edinburghand of Glasgow, and at Achilles and the Tortoise, a conference on Norms and Reasoning held at the University of Glasgow. For helpful comments on those and other ancestors of the paper, I am grateful to George Bealer, Alex Byrne, Mark Crimmins, GarrettCullity, Berys Gaut, Alvin Goldman, Ned Hall, Gilbert Harman,Leonard Katz, Penelope Maddy, Elizabeth Telfer, Judith Jarvis Thomson, Timothy Williamson, Nick Zangwill, and two anonymous referees.
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