Presentation on theme: "Truth as the aim of epistemic justification"— Presentation transcript:
1Truth as the aim of epistemic justification Asbjørn Steglich-Petersen Department of Philosophy University of Aarhus
2‘Believing aims at truth’ Many philosophers have been attracted to the idea that beliefs ‘aim’ at truth.Some understand this in normative terms, as expressing a fundamental norm of correctness for belief, e.g. that believing P is correct (if and) only if P is true.Others (me included) understand it in teleological terms, as the claim that when a person believes that P, she has the aim of believing P truly (or has some sub-intentional surrogate of such an aim).The teleological account entails a criterion of success: believing P is successful (with respect to the truth-aim) if and only if P is true.However: the problem I wish to discuss is relevant for both normativists and teleologists about the truth aim.
3Truth and guidanceMost defenders of the truth aim recognize that truth cannot be the only relevant consideration when evaluating belief.The problem is that the truth of a proposition, in itself, offers little guidance for someone wishing to form a belief about it.It seems that the mere truth of a proposition doesn’t make it the case that I ought to believe it, nor does its falsity make it the case that I ought to disbelieve it.The additional relevant consideration is often expressed in terms of epistemic justification, or a requirement that beliefs are adequately backed by epistemic reasons.
4The truth aim and justification The mere fact that truth cannot be the only relevant consideration raises several issues:If truth doesn’t determine when a belief is justified, what does?If beliefs can be evaluated both in terms of truth and justification, what is the relation between those kinds of evaluation? It would be odd if they are completely distinct.If epistemic justification determines what a person ought to believe in any given situation, is there any reason to hold on to evaluation in terms of truth? Is the truth aim then obsolete?
5A simple accountMany have been attracted to a simple account of the relationship between justification and the truth-aim, which answers all of the above worries:The point of the requirement that we only believe what we are justified in believing is to advance the ultimate aim of believing the truth about the relevant propositions. We seek justification for our beliefs in order to believe the truth.Apart from being strikingly simple, this account has what many regard as the virtue of assimilating the normativity of epistemic justification to instrumental normativity, which many find relatively unproblematic. This is so especially in the context of a teleological understanding of the truth aim.
6A problemAs a number of philosophers have pointed out, however, there is a basic problem with the simple account: it is forced to denying the possibility of justified false beliefs.There are a number of arguments for this claim floating in the literature. I shall focus on Stephen Maitzen (1995) and Richard Fumerton (2001; 2002).A similar argument (citing Fumerton 2001) has recently been invoked by Kathrin Glüer and Åsa Wikforss (2009: ), as a part of an attack on the idea of beliefs aiming at truth.
7Maitzen’s argument Maitzen starts with a simple argument: Suppose for reductio that the point of justification is to advance the aim of believing only truths.It follows that beliefs are justified if they advance that aim, and unjustified if they don’t.But only true beliefs will advance the truth aim.So beliefs are justified only if they are true, which, according to Maitzen is an absurdity. So, the point of justification cannot be to advance the aim of believing only truths
8Maitzen’s argumentThe obvious response to this simple argument is that the justification of a belief doesn’t depend on whether the belief itself furthers the truth aim, but whether the methods by which it was formed tends to further the truth aim.But according to Maitzen, this response results in a dilemma: either the justifying methods will be inconsistent with the ultimate aim of truth, or they will disallow justified true beliefs.The dilemma is a version of the well-known dilemma for rule- utilitarianism: either the rules will be inconsistent with the basic aim of maximizing utility, or the rules will effectively recommend the same as, and thus collapse into act-utilitarianism.There is a further similarity between these two dilemmas: many have been attracted to rule-utilitarianism because it seems to provide guidance, as opposed to the act-based version. Analogously, the justification norm is needed because the truth norm cannot guide.
9Fumerton’s argument Fumerton’s argument is even simpler: Suppose for reductio that justification gets its point from advancing the aim of believing what is true with respect to some specific proposition P.The only way of advancing the aim of believing what is true with respect to P is to believe P when P is true.So if the point of justification is to advance that aim, whatever the exact content of the justification norm might be, it cannot allow justified false beliefs.But that is absurd, so the supposition fails.Further, identifying justification what what one is justified in believing will advance the aim of believing what is true with respect to some proposition would be circular.
10In a nutshellIf the aim of justifying one’s beliefs is to end up believing the truth, success in justifying a belief must entail that the belief is true.But it is possible for a false belief to be justified; it is possible for a belief to be successfully justified but not true.So the aim of justifying one’s beliefs cannot be that of ending up believing the truth.
11My strategyIn the following I shall defend the simple account of justification as an instrument to believing the truth, by arguing that we can reject a crucial premise: that there cannot be justified false beliefs (at least in the relevant sense of ‘justification’).I first define the sense of ‘justification’ that is relevant to our purposes.The then consider three popular intuitions in favor of the possibility of justified false beliefs, and find them wanting.Finally, I sketch an alternative account of justification that does not allow justified false beliefs, and show how the account is less unpalatable that commonly supposed.
12‘Justification’The sense of ‘justification’ relevant to our purposes, is the sense which addresses the problem that truth by itself doesn’t provide guidance. This can be understood in terms of reasons.In asking whether some fact could justify S in believing P, I shall focus on whether that fact could act as an adequate epistemic reason for which S believes that P.A type of fact justifies S in believing P, in this sense, if mentioning that a fact of that type obtains would be an adequate, i.e. sufficient, answer on S’s behalf to the question ‘what gives you epistemic reason to believe that P?’Call this the ‘reasons constraint’ on the relevant sense of justification.Although this may seem like not much of a constraint, some notions of justification fails to satisfy it.With this in mind, we can go on to consider the three popular intuitions.
13ProbabilismThe first popular intuition in favor of the possibility of justified false beliefs is what I call ‘Probabilism’:Probabilism: when the evidential probability for S that P is sufficiently high, but not necessarily 1, S has justification for believing that P.The thesis does not amount to a definition of justification, but is a mere sufficiency claim. We needn’t consider an analogous necessity claim.The thesis concerns propositional justification rather than doxastic justification.The thesis is silent on the access S must have to the antecedent condition in order for it to justify the belief. I shall leave this issue for now, but in the meantime note that it makes sense to ask: ‘Suppose that R is the case, and S has adequate access to R, would R then be an adequate reason for S to ϕ?’. My criticism of Probabilism grants the relevant access, and concerns this latter question only.
14ProbabilismProbabilism allows justified false beliefs, since it is possible for a proposition to have an arbitrarily high evidential probability short of 1, and yet be false.Lotteries provide an especially vivid example where this is the case: it has seemed plausible to many that if S holds a single ticket in a large fair lottery, and knows this, S has justification for believing that she will loose, despite the slight but real possibility that she won’t.My argument against probabilism has two components: I first argue that probabilism is committed to allowing an irrational or even paradoxical practice of belief formation (what I call ‘doxastic risk’), and later argue that the appeal of probabilism can be accounted for in other ways.
15Doxastic riskAn action is taken under risk whenever the agent has mere probabilistic knowledge of the states of nature relevant to the success of the action (standard decision theoretic definition).The states of nature relevant to the success of forming a belief, are the states in nature in which the proposition believed is true and false, respectively.This yields the following definition of doxastic risk:Doxastic risk: when S forms a belief that P while having mere probabilistic knowledge that doing so will result in believing P truly, S forms the belief under risk.
16Doxastic risk is paradoxical When action is performed under risk, or at least perceived risk, the agent performs the action in the hope that a particular outcome will ensue. She doesn’t believe that it will ensue, since if she did, she wouldn’t regard the action as risky.This means that there is something paradoxical about the notion of doxastic risk, since in this case, the risky ‘action’ is exactly a belief that the success condition for the action will ensue, which contradicts the idea that it was performed under risk.One cannot consistently regard oneself as taking a risk in some particular act if one knows that taking the act will entail not regarding the action as risky.
17Doxastic risk is paradoxical Might this paradoxical situation be resolved by observing that ‘under risk’ refers to the agent’s doxastic situation prior to completing the act?For example, bringing an umbrella on a walk might be risky in the sense that I, prior to and during portions of the walk, am unsure that it will rain. This risk is compatible with me coming to believe that it rains, if it indeed starts to rain.Analogously, perhaps all it takes for a belief that P to be risky, is that it was formed while the agent was unsure whether P. This is compatible with no longer being unsure whether P once the belief that P is formed.But in contrast to the umbrella-case, such a change in doxastic state would either be unfounded, founded upon the very doxastic state it is a revision of, or founded on new evidence. But neither of these options are very attractive for the Probabilist.
18Doxastic risk is irrational It seems, in fact, that forming a belief under doxastic risk will always result in rationally incompatible beliefs:Suppose that S finds that the probability of P upon her evidence is .6 (call this her ‘evidential belief’), and suppose for the sake of argument that .6 is the Probabilist threshold of evidential probability for justified belief.Since one can form a belief in response to an evidential belief only if one doesn’t thereby revise the evidential belief, Probabilism then recommends that S both believes that evidential probability that P is .6 and believes that P. These seem like rationally incompatible beliefs.The obvious response is to raise the threshold to some value higher than .6, but short of 1. But there does not seem to be any value short of one, which would make the evidential belief and the outright belief rationally compatible.
19Doxastic risk is irrational It may be objected that since P, and the proposition that the probability of P upon a person’s evidence is some value short of 1, can both be true at once, that person can believe both propositions without contradiction, and thus without irrationality.But the fact that two propositions can be true at once does not make the pair of those propositions available for rational belief. Moorean absurdities (‘P and I do not believe that P’) provide examples of this.
20Doxastic risk is irrational Still, some may insist that judging belief in such pairs of propositions irrational begs the question against Probabilism. But consider the role of such pairs in rationalizing action:Suppose that S has to decide whether to ϕ where the success of ϕ-ing is P-dependent.Suppose that S believes both that P and that the probability of P upon her total evidence is .9.It is not difficult to imagine situations in which she should ϕ in response to the one belief, but not in response to the other, thus leaving the agent with conflicting recommendations.
21Doxastic risk is irrational It is no help for the Probabilist to claim that the evidential belief is relevant to the rationality of action only via rationalizing an outright belief, since in the context of an action, the rationality of which depends on the exact probability that it will be successful, it should strike us as especially implausible to let an evidential probability short of 1 justify an outright belief.Nor is it a help to point to decision theoretic rules taking probability intervals or fuzzy probability regions as inputs, since by hypothesis, no such intervals or fuzzy probabilities exist in the case at hand.So it seems that Probabilism is committed to an irrational practice of belief formation.
22Credence probabilismThe obvious Probabilist reply to the above difficulties is to retreat to a principle concerning the justification of degrees of credence:Credence probabilism: when the evidential probability for S that P is D, S has justification for adopting credence in P to degree D.But this doesn’t in itself say anything about the justification of outright belief. To that end we need a bridge principle connecting justified credence to justified belief.One such popular principle is the Lockean Thesis:The Lockean Thesis: Outright belief that P = Any degree of credence above threshold T.These two principles jointly imply that when the evidential probability for S that P is above a certain threshold short of 1, S will be justified in an outright belief that P. But since this belief is ‘really’ just a degree of credence, it does not count as ‘risky’ in the problematic sense.
23Credence probabilismHowever, the combination of credence probabilism and the Lockean Thesis gives rise to new problems.Consider the following plausible thesis about the justification of assertion:The belief-assertion principle: when S is epistemically justified in believing P, S is epistemically justified in asserting P.If this is correct, Credence probabilism and the Lockean Thesis entail that when the evidential probability for S that P is above a certain threshold short of 1, S is justified in asserting that P. But that seems false (cf. Williamson 2000: 246).So either Credence probabilism or the Lockean Thesis have to go, but giving up either will block Credence probabilism as a response to the problem of doxastic risk.In sum: Probabilism does not look very promising…
24ReliabilismThe second main intuition in favor of the possibility of justified false beliefs, we can call Reliabilism:Reliabilism: when S has formed her belief that P according to methods that reliably (but not invariably) result in true beliefs, S is justified in believing P.Note that for ease of expression, Reliabilism is formulated as a principle about doxastic rather than propositional justification.Note also that although Reliabilist theories are not usually designed to satisfy the reasons constraint, but instead define conditions under which a belief can be justified even in the absence of any explicit reasoning on behalf of the believer, it seems that something could satisfy those latter conditions only if they could also satisfy the reasons constraint.Not all Reliabilist theories of justification allow justified false beliefs (Armstrong 1973 and Williamson 2000 don’t), but most do. The following discussion concern only those that do.
25ReliabilismThere are at least two broad ways one might interpret the notion of reliability involved.The most common interpretation is in terms of the relative frequency with which beliefs formed in accordance with the relevant methods are true.On this interpretation, Reliabilism is just a special case of Probabilism, since the method justifies believing P in virtue of the fact that by forming the belief in accordance with the method, the agent raises the chance of ending up with a true belief to a certain level (short of 1).My response to this kind of Reliabilism will thus be the same as my response to Probabilism.
26ReliabilismThe second possible interpretation understand ‘reliable method’ in terms of what normally happens when a belief is formed in accordance with it, where ‘normally’ expresses something else than mere likelihood.When what is normal fails to occur, some explanation of this is required, whereas this is not necessarily the case when what was likely fails to occur. Hence:Reliabilism Normal: when S has formed her belief that P according to methods that are such that, were the belief to be false, this would require an explanation, S is justified in believing P.Smith (forthcoming) gives a compelling illustration of the difference between what is normal, and what is likely.However: it seems an odd reason to believe a proposition that it is formed in accordance with a method that is such that it would require an explanation if the belief turned out false. But in order to substantiate this claim, I must first consider the last of the three intuitions in favor of justified false beliefs.
27BlamelessnessThe third main intuition in favor of the possibility of justified false beliefs, I call Blamelessness:Blamelessness: when the epistemic situation of S is such that S couldn’t be blamed for believing P even if P is false, S has justification for believing P.The possibility of justified false beliefs does not follow immediately from this intuition, but when coupled with the commonplace observation that we frequently are blameless for false beliefs, it does.Vivid examples include skeptical scenarios, but it is easy to imagine more everyday cases. For example, one can be mislead by testimony that one has no reason to distrust.
28BlamelessnessThere can be no doubt that we can be blameless for believing a falsehood, but it should also be clear that Blamelessness doesn’t satisfy the reasons constraint, and thus fails to pick out conditions under which a belief is justified in the defined sense.Prima facie, the fact that one would be blameless for believing P is a not an adequate reason for S to take up a belief that P. This prima facie judgment can be backed up in the following way:Note first that for any norm N, we can distinguish between the conditions under which an agent conforms to N, and the conditions under which the agent is blameless for failing to conform to N. There is a real difference: when trying to conform to a norm, we do not (merely) try to satisfy the conditions for being blameless if we fail to conform.Given this distinction, if Blamelessness is a genuine norm that we ought to conform to when forming beliefs, there must be a set of conditions under which we are blameless for failing to conform to Blamelessness. But that is absurd: there is no set of conditions under which we are blameless for failing to be blameless in forming a belief. So Blamelessness should not guide us when forming beliefs.
29Reliabilism againI noted above that it seems an odd reason to believe a proposition, that it is formed in accordance with a method that is such that it would require an explanation if the belief turned out false. We can now locate the source of this oddness.Observe first that in order for S to be blameless for believing a falsehood, there must be an excusing explanation for that belief.The fact that the proposition was likely given S’s evidence is not sufficient for this, since unlikely events may be statistically on a par with their alternatives.On the other hand, it seems that if S formed her belief according to methods that are such that, were the belief to be false, this would require an explanation, such an explanation would also suffice to excuse S from blame.
30Reliabilism againThis suggests the following bold hypothesis: the antecedent conditions of Reliabilism Normal and Blamelessness are identical, since the explanations required for justifying a false belief are the same.Since what the norms recommend is also identical, the norms would just be two ways of expressing the same thought, and any argument against the one norm would also be an argument against the other. So if Blamelessness shouldn’t guide belief formation, Reliabilism Normal shouldn’t either.This does not entail that it is uninteresting to ask whether a person was blameless in her false belief. It is frequently of great importance, for example when deciding whether a person acted in good faith. There may even be a sense of ‘justification’ that would be the proper label for this condition.But if what we are interested in is the norm that ought to guide us when forming beliefs, Blamelessness, and hence Reliabilism Normal, is not it.
31A (too?) radical solution The problem for the simple account of justification as truth aiming, raised by Maitzen and Fumerton, presupposed that there can be justified false beliefs.I have argued that some of the most common intuitions in favor of this possibility fail, at least when it comes to the relevant sense of ‘justification’.I must now argue than an account of justification on which justification entails truth is less unpalatable as it has seemed to many.
32A (too?) radical solution The principle I must defend is what I call Implication:Implication: S has justification for believing P (if and) only if the truth of P is implied by S’s evidence.Read as a biconditional, Implication simply identifies propositional justification for believing P with P being implied by one’s evidence.But for our purposes, it might suffice to establish the weaker claim that it is necessary for having propositional justification for believing P, that P is implied by one’s evidence.If the biconditional is true, Implication certainly satisfies the reasons constraint: the fact that P is implied by S’s evidence would be adequate as a reason for S to believe that P (given the proper access – more on this later). But in what follows, I shall focus on defending the weaker necessity claim against three key objections.If evidence is factual (which I shall assume), both versions entail that a belief can be justified only if it is true.
33The demandingness objection I shall consider three objections to the proposed account. The first, I call the ‘demandingness objection’:Many will have the intuition that there could be less demanding conditions sufficing as adequate reason to believe some proposition. Will the present proposal not have the result that most of the beliefs that we commonly regard as justified won’t be?There are (at least) three mitigating considerations worth pointing to in response.
34The demandingness objection The first mitigating considerations is that in many cases where we wish to form a belief about P, but P is not implied by our evidence, a proposition about the evidential probability that P is implied by the evidence, providing justification for believing that probabilistic proposition instead.This is not always the case. There are cases in which the fact that the evidential probability for S that P is D will not be implied by S’s total evidence, since even if E is S’s total evidence, E does not imply that S’s total evidence includes E or that E includes S’s total evidence (thanks to Tim Williamson for this point).But in cases where the agent has access to those latter facts, the probabilistic proposition is implied by the evidence.So even if we are never justified in believing a falsehood, we often have justification for believing a proposition to be very likely, which nevertheless turns out false.
35The demandingness objection This suggests the possibility that those who have found it plausible that we can be justified in believing a falsehood, have done so because of confusing being justified in believing a proposition, and being justified in believing that proposition to be very likely. This would explain the allure of Probabilism.This theory is supported by the fact that the psychological reaction (e.g. surprise) upon discovering that a proposition is false, is likely to be very similar, given the two kinds of prior attitude, even if the probabilistic belief is not strictly speaking falsified by the falsity of the proposition believed to be likely.What is more justified beliefs concerning such likelihoods are sufficient as grounds for rational action. They can play the same role in decision theory as rational degrees of credence.
36The demandingness objection The second mitigating consideration is that in cases where we lack epistemic justification for believing some proposition, we may nevertheless be justified in accepting that proposition for some restricted range of purposes, where this justification will involve a combination of epistemic and non-epistemic factors (Cohen 1992).There may be cases, for instance, where the computing costs of relying on probabilistic beliefs in deciding what to do exceeds the potential benefits of doing so, it which case it is reasonable to instead rely on acceptances of the truth of some simple non- probabilistic proposition.This suggests the possibility that we may sometimes confuse what we regard as justification for believing P, with what is really just justification for accepting P.
37The demandingness objection The last mitigating consideration is that Implication says nothing about the conditions under which one can be held blameless for believing a false proposition.Plausibly, one condition for being blameless is that one made an honest attempt at forming a justified, and thus true belief. As suggested above, another condition might be that an explanation would be required to make sense of how the belief could be false given the evidence available to the believer.No doubt, there are many more complex and important things to be said about these conditions, and there is no harm done in continuing to use the term ‘justification’ to speak of them, as long as one keeps in mind that those conditions cannot act as antecedent conditions in a norm that guides agents when forming beliefs.But the feeling that Implication is too demanding may just come down to confusing justification in the sense defined with the conditions for being blameless for one’s beliefs.
38The guidance objection The second objection I shall consider concerns the ability of the proposed justification norm to guide belief formation.The point of supplementing the truth norm with a justification norm was that the truth of a proposition in itself offers little guidance in whether to believe it. Even if my toaster is on back in Aarhus, I have no reason to believe that it is.But since I have assumed evidence to be factual, and it also is a factual question whether some proposition is implied by one’s evidence, does the proposed norm of justification really provide more guidance than the simple truth norm?But on any account of evidence, the propositions acting as evidence, and the implications of these propositions, are the kinds of truths that we can be assumed to have some degree of access to. This doesn’t mean, of course, that evaluating one’s evidence in order to apply the justification norm is cognitively effortless or trivial. But that doesn’t mean we cannot be guided by the justification norm, or that we can be guided by it only by relying on some more ‘basic’ norm with yet more transparent antecedent conditions (cf. Williamson 1998: 102).
39Unjustified true beliefs? The final objection stems from the possibility of unjustified true beliefs.The initial problem was that if the aim of justification is to end up believing the truth, there cannot be justified false beliefs (beliefs that are successful vis-à-vis the aim of justification, but not successful vis-à-vis truth). I have argued that we can accept that implication.But there might be a parallel argument: if the aim of justification is to end up believing the truth, there cannot be unjustified true beliefs (beliefs that are successful vis-à-vis truth, but not successful vis-à-vis justification).That would be an unacceptable result: clearly one can have true but unjustified beliefs! (Thanks to Tim Williamson for raising this issue).This problem resembles the ‘Swamping Problem’: if the purpose of justification is to ensure true beliefs, we cannot explain why an unjustified true belief is less valuable than a justified true belief, since the value we wanted to promote by justifying the belief already obtains.
40Unjustified true beliefs? Although I cannot deal with this problem in full here, a first response might be this: while successfully justifying a belief requires that the belief is true, this is not all it takes for justifying a belief. Truth is necessary, but not sufficient for justification.This fact is already part of the offered account: truth is necessary but not sufficient for a proposition to be implied by one’s evidence. The fact that there can be true but unjustified beliefs does not threaten that truth is one of several criterions of success for justification.But this might spoil what I called ‘the simple account’, according to which the point of justifying one’s beliefs is to end up believing the truth. It may entail that there are several aims of justification, e.g. believing the truth and believing what is implied by one’s evidence.That might be OK: it wouldn’t beg the question against Maitzen and Fumerton, whose arguments could just as well be taken as arguments against truth being one of several aims of justification.But we might doubt that the proposed account really is committed to several aims. After all, does ϕ-ing in order achieve aim A entail that one aims both at ϕ-ing and achieving A?
41Conclusion I have argued for two main claims: That three popular intuitions in favor of the possibility of justified false beliefs fail, at least as far as the relevant sense of ‘justification’ is concerned.That an account of justification which requires that the truth of the justified proposition is implied by the agent’s evidence is less unpalatable than commonly supposed.