Evidence and Access

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EVIDENCE AND ACCESS Clayton Littlejohn In this paper, I want to discuss a problem that arises when you try to combine an attractive account of what constitutes evidence with an independently plausible account of the kind of access we have to our evidence. According to E = K, our evidence consists of what we know. According to the principle of armchair access, if a proposition is part of our evidence we ought to be able to know that this proposition is part of our evidence ‘from the armchair’. C
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   1  EVIDENCE AND ACCESS  Clayton LittlejohnIn this paper, I want to discuss a problem that arises when you try tocombine an attractive account of what constitutes evidence with anindependently plausible account of the kind of access we have to ourevidence. According to E = K, our evidence consists of what we know.According to the principle of armchair access, if a proposition is part of our evidence we ought to be able to know that this proposition is part of our evidence ‘from the armchair’. Combined, these claims entail thatwe can have armchair knowledge of the external world. Because itseems that the principle of armchair access is supported by a widelyshared intuition about epistemic rationality, it seems we ought toembrace an internalist conception of evidence. I shall argue that thisresponse is mistaken. Because externalism about evidence canaccommodate the relevant intuitions about epistemic rationality, theprinciple of armchair access is unmotivated. We also have independentreasons for preferring externalism about evidence to the principle of armchair access.0 INTRODUCTION  I want to discuss a problem that arises once we try to accommodate two independently plausible claimsabout evidence. The first is a claim about what our evidence consists of. It is the claim that evidenceconsists of knowledge:(E = K) S’s evidence includes  p iff S knows  p . 1  The second is a claim about the kind of access we have to our evidence. It is the claim that we have‘armchair access’ to our evidence:(AA) If S’s evidence includes  p , it is possible for S to know from thearmchair that  p is part of S’s evidence. 2    1 Williamson (2000) defends this view. Brewer (1999), Hyman (1999, 2006), Maher (1996), McDowell(1988), and Unger (1975) face essentially the same difficulty that Williamson faces insofar as their views canaccommodate AA only if it is possible to have armchair access to contingent matters of fact. 2 An anonymous referee asked whether armchair knowledge and apriori knowledge amounted to the samething. That is hard to say. If you think that apriori knowledge does not include introspective knowledge,these notions do not come to the same thing. Armchair knowledge might include apriori knowledge (e.g.,knowledge of moral truths or mathematical truths that is had by reflection or intution), but it would alsoinclude introspective knowledge of one’s own mental life. Silins (2005) defends the principle of armchairaccess as it is stated here. Audi (1993: 344), Ginet (1990), as well as Conee and Feldman (2004: 47) seemto endorse the principle as well. Just to be clear, it is not obvious that if S has armchair knowledge that  p ispart of her evidence she must have armchair knowledge that  p is the case. Perhaps S can have armchairknowledge that the proposition that she has hands is part of her evidence even if she does not know that shehas hands.   2  To say that S knows something from the armchair is to say that it can be known in a way that does notdepend constitutively upon experience. It is to say, in other words, that if   p is part of S’s evidence, it should be possible for S to know that  p is part of S’s evidence on the basis of introspection or reflection. Theprinciple is  prima facie plausible because it often seems that when we make non-culpable mistakes about howthings are in the external world, the mistakes do not derive from prior mistakes about what our evidenceconsisted of. Upon learning that we were mistaken, we tend to think that our evidence misled us and notthat we were misled about what our evidence was. That is, we often think that when we make mistakesabout how things are in the external world, we discover that there was something we were right about (e.g.,what reasons we had for making the mistaken inference) and that what we were right about had to concernsome subject matter other than what we were mistaken about (e.g., considerations that pertained to us andhow things seem to us rather than how things are outside of us).To see what the problem is, let’s suppose for the sake of this discussion that the sceptic is wrong.Suppose that it is possible to know contingent propositions about the external world such as the propositionthat I have hands. Given this supposition and E = K, it follows that:(E1) My evidence includes the proposition that I have hands.It follows from AA that:(E2) It is possible for me to know that (E1) is true from thearmchair.If E = K can be known from the armchair, it follows from this further assumption, AA, (E1), and (E2) that:(E3) It is possible for me to know that I have hands from thearmchair.But, that seems absurd. It seems absurd to think that I could know from the armchair that I have hands. 3  Our problem is at least superficially similar to the problem that McKinsey raised for externalismabout thought content. 4 If the contents of our thoughts depended upon contingent matters of fact externalto us (e.g., the presence of water), how could we consistently say that we have privileged access to our  3 Neta and Pritchard (2007) seem prepared to bite this bullet. 4 For discussion, see McKinsey (1991). While this is controversial, I believe that McKinsey’sepistemological objections to thought content externalism rest on a mistake about the commitments of thought content externalism. If Putnam is right, we might know apriori that ‘water’ thoughts are wide butnot that our ‘water’ thoughts depend upon the existence of water. (Our ‘water’ thoughts would have beenwide in a dry world.) So, there is nothing we know apriori that allows us to knowingly deduce from thearmchair that water exists if we know from the armchair that we are thinking that water is wet and knowfrom the armchair that such thoughts have wide content. And, I doubt that knowing whether a thought isworld-dependent in the way our ‘water’ thoughts happen to be but ‘unicorn’ thoughts happen not to be isnecessary for knowing what we are thinking. I do not believe that critics of externalism about evidence havemade any analogous mistakes about the commitments of evidential externalism, but I need not take a standon that matter in this paper.   3  thoughts and insist that we cannot have privileged access to those aspects of the external world that gotowards determining what the contents of our thoughts are? If our evidence depended upon contingentmatters of fact external to us, how could we consistently say that we have a kind of privileged access to ourevidence if we do not have a similarly privileged access to those aspects of the external world that gotowards determining what our evidence consists of? Here, I shall defend an incompatibilist response.Perhaps we cannot reconcile externalist conceptions of evidence with the principle of armchair access. Weshould reject the principle of armchair access and recognize that externalism about evidence canaccommodate the considerations taken to motivate the principle of armchair access.In §1, I shall explain some of the motivation behind the principle of armchair access and externalistapproaches to evidence that appear to be at odds with this principle. In this section, we shall see whysomeone might think that the principle of armchair access is needed to make sense of a widely held intuitionabout epistemic rationality. In turn, we shall see why someone might think that externalism about evidenceought to be rejected on the grounds that it clashes with our intuitions about epistemic rationality. In §2, Ishall explain why we ought to give up the principle of armchair access. Not only is there a good case to bemade for externalism about evidence, the principle of armchair access appears to generate some scepticalheadaches. It is not obvious that the principle of armchair access is incompatible with the anti-sceptical viewthat we can have knowledge of the external world, but we shall see that it is incompatible with the anti-sceptical view that we can have non-inferential knowledge of the external world. In §3, I shall explain howto reconcile an externalist approach to evidence with the considerations having to do with epistemicrationality often taken to motivate an internalist approach to evidence and the principle of armchair access.1 EVIDENTIAL EXTERNALISM AND ARMCHAIR ACCESS  In this section, I want to explain why someone might think that our evidence is limited to that which we canknow belongs to our evidence from the armchair and explain why others think that our evidence consists of propositions that do not satisfy this access requirement. Before we get to that, some preliminary remarksabout the notion of evidence at issue are in order.First, we typically think of evidence as being evidence   for  some particular claim, belief, orhypothesis. It might seem strange to some to think of a subject’s evidence as being coextensive with whatthe subject knows since it is not obvious that in knowing  p it is necessary that  p is evidence   for  some furthermatter. 5 Since evidence is always evidence   for  something or other, doesn’t this show that there’s somedifference between pieces of evidence and items of knowledge? It might be useful to distinguish the  5 An anonymous referee for this journal expressed the concern that E = K commits us to an overly inclusiveconception of evidence, but I should hope that E = K is consistent with (a) any plausible view about when  p  can count as a subject’s evidence for q and (b) the insistence that nothing can be evidence simplicter  unless it isevidence   for  something or other.   4  propositions that are a subject’s evidence   for  believing some particular proposition and the subject’s evidence simpliciter  . To understand this talk of evidence simpliciter  (i.e., talk about evidence that does not mention anypropositions the piece of evidence is evidence for), I find the following analogy useful. 6 We can say thatsomeone has such and such piece of evidence without specifying what that is evidence for much in the sameway that we can list the ingredients in someone’s kitchen without saying what those ingredients areingredients for. This should not be taken to support the dubious idea that there could be ingredients simpliciter  that are not ingredients for anything at all and we similarly should be able to talk about what is inan individual’s stock or fund of evidence without being taken to support the bizarre idea that there arepropositions that are evidence simpliciter  that is not evidence   for  anything. According to E = K, nothing getsto be part of that fund of evidence unless the subject knows that the proposition is true and nothing beyondknowledge is necessary for getting a proposition into that fund. It seems we can consistently add that noneof these propositions are evidence simpliciter  unless they are evidence   for  something or other. I cannot thinkof a case in which there is a proposition I know that could not serve as evidence for something I mightconsider believing. When I say that  p is part of a subject’s evidence without specifying what proposition(s)that proposition is evidence   for  , it is like saying that someone is a brother or aunt without saying to whomthis person is a brother or an aunt.Second, some authors find it helpful to distinguish between objective and subjective conceptions of evidence. On an objective conception of evidence such as Achinstein’s conception of veridical evidence, itcannot be that  p is evidence for S’s belief that q unless  p is true. 7 I see nothing wrong with acknowledgingthat we do use this concept of evidence while acknowledging that we also use something along the lines of Achinstein’s subjective conception of evidence on which it can be the case that  p is S’s evidence for q even if   p is false (unbeknownst to S). Once we distinguish objective from subjective conceptions of evidence, thequestion arises as to which concept of evidence is at issue. One might worry that unless we fix on somesingle notion, there is the possibility that both sides to this debate will be talking past one another. Yes,someone might say, you should not combine E = K with AA because the former has to do with an objectivenotion of evidence whereas the latter has to do with a subjective notion. It is not surprising that if youignore this fact and try to combine the two you’ll run into trouble, but don’t we solve the ‘problem’ westarted with once we disambiguate?I don’t think that we can solve (or dissolve) our problem so easily. First, think about the dialecticalsituation. Those who defend AA often taken it upon themselves to argue that the incompatibility betweenAA and E = K is reason to reject E = K. I doubt that either party to this dispute could have thought that E =K was ever intended as an account of the subjective conception of evidence. Those who defend AA  6 Hyman (2006: 892). 7 See Achinstein (1984).
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