In this paper I examine Williamson’s (2000) claim that all evidence is propositional. I propose to reject this claim. I give two objections to two premises of Williamson’s argument. The first is a critique of Williamson’s claim that we choose between hypotheses on the basis of our evidence. The second objection is that Williamson’s claim that evidence is an explanandum of an hypothesis leads to counter-intuitive consequences and thus is not central to what evidence is, at least on an ordinary understanding

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“09logins”2013/9/2page 347✐✐✐✐✐✐✐✐Logique & Analyse 223 (2013), 347–354ON WILLIAMSON’S ACCOUNT OF PROPOSITIONAL EVIDENCE∗ARTURS LOGINSAbstractIn this paper I examine Williamson’s (2000) claim that all evidenceis propositional. I propose two objections to key premises of Willi-amson’s argument. The first is a critique of Williamson’s claim thatwe choose between hypotheses on the basis of our evidence. Thesecond objection is that Williamson’s claim that evidence is an ex-planandum of a hypothesis leads to counter-intuitive consequences.1. IntroductionIn his influential book Knowledge and its limits Timothy Williamson (2000)has claimed that all evidence one possesses is propositional. This, in turn,is a necessary premise for the argument to the conclusion that all and onlyevidence is knowledge (E=K).1The focus of this paper is to raise objections to Williamson’s propositionalaccount of evidence. I claim that even if, on my account, the E=K equationcan be maintained, it nevertheless grounds a more permissive account ofwhat evidence is.I propose to re-examine Williamson’s argument, offering some critical re-marks and objections. In section 2, I present Williamson’s argument forthe propositional nature of evidence. In section 3, I provide two argumentsagainst two premises of Williamson’s argument, namely the claim that evi-dence enables us to choose between hypotheses and, secondly, the claim thatit is central for evidence to be an explanandum of an explanation. I show thatthis claim has some serious problems because of ambiguity in what is meantby explanation. I show that Williamson’s account has some very counter-intuitive consequences.∗The research leading to this paper was supported by the Swiss National Science Foun-dation (SNSF) grant number 100015 131794. I would like to thank Brian Ball, Pascal Engel,Davide Fassio, Matthew Kennedy, Kevin Mulligan for their comments and discussions. Ear-lier materials from this paper were presented at VAF IV conference in Leuven January 2010and in Phileas Talks in Geneva December 2009.1 Since for Williamson (2000) there is only propositional knowledge.“09logins”2013/9/2page 348✐✐✐✐✐✐✐✐348 ARTURS LOGINS2. Williamson on propositional evidenceThe point of departure for Williamson’s (2000) argument for the proposi-tionality of evidence is the claim that what evidence does is enabling us tochoose between competing hypotheses. Williamson (2000) claims (premise1) that “we often choose between hypotheses by asking which of them bestexplains our evidence” (p. 194). This choice that we are making betweencompeting hypotheses is determined by Inferences to the Best Explanations(IBE) whereby which hypothesis we choose is the one that best explains theevidence. Williamson claims here that we are (often) using IBEs to providean explanation for some evidence.2 From this follows (premise 2), namelyevidence is what a hypothesis explains3 (p. 195).The next step of the argument is the claim (premise 3) that if a hypothesisexplains an item, then this item must be of a propositional kind, whilst nextpremise (premise 4) states that an item which is explained by a hypothesisis propositional (p. 195). From this follows (the conclusion) that evidence ispropositional.For the argument to work Williamson needs to show that the premises ofthe argument are true. Especially central premises — premises 2 and 3 —should be motivated. Premise 2 contains an assumption that evidence is anexplanandum of a hypothesis (Evidence as Explanandum of an Hypothesis(EE)) and premise 3 contains an assumption that what a hypothesis explainsis (necessarily) propositional (Propositionality of Explanandum (PE)).According to Williamson’s argumentation the assumption (EE), as thecontent of the premise 2, is grounded, because it is implied by premise 1.He argued for premise 1 by observing that it is in our usual, ordinary prac-tice to choose between hypotheses on the basis of evidence (by the Inferenceto the Best Explanation). The fact that IBE is providing explanations showsthat it is crucial for evidence to be an explanandum of a hypothesis.With regards to premise 3 (or the (PE) assumption) Williamson arguesfor it by showing that it can’t be the case that there is something which isa kind of thing which a hypothesis explains, but which at the same time isnot propositional. This is shown, according to Williamson by considering“that-clauses”. The main idea is that the kind of thing which a hypothesis2 Notice that Williamson’s argument is itself an implicit IBE — the assumption that it isa central function of evidence to serve in the IBE is (an attempt to) the best explanation ofour ordinary, regular use of evidence. But Williamson himself affirms that IBE is not alwaysacceptable, as when he claims that “[e]ven if inference to the best explanation is not legitimatein all theoretical contexts. . . ” (p. 194). One could doubt whether this highly theoretical caseis a case where IBE is acceptable.3 This holds because it is an exemplification of this schema: (ii) is implied from (i) where— (i) x is explained by a hypothesis through an IBE and (ii) x is explained by a hypothesis.“09logins”2013/9/2page 349✐✐✐✐✐✐✐✐ON WILLIAMSON’S ACCOUNT OF PROPOSITIONAL EVIDENCE 349explains must have a structure which respects “that-clause” structure, other-wise it will not be possible to explain it properly. Williamson argues that asingle word does not give an explanation (is not a proper explanation) sinceexplanation must be structured by “that-clauses” (p. 195). And it is never thecase, according to Williamson that something that is the kind of thing whichhypotheses explain doesn’t have a structure expressed by ‘that’ clause.4To sum up, this is the structure of Williamson’s argument (PropE):(1) (EE) is grounded in our usual epistemic practice (evidence is whatserves in our Inferences to the Best Explanation (IBE)).(2) Thus, by inference to the best explanation of (1), (EE): x constitutesevidence iff x is explanandum of a hypothesis (is what a hypothesisexplains).(3) (PE): x is explained by a hypothesis only if x is propositional.(4) (PE) is grounded in our language use — viz. the use of “that clauses”plus the assumption that “that clauses” enable us to give sufficientlyspecified explanations (i.e. an unspecified x (= without a “thatclause”) is a source of infinity of propositions and cannot constitutean explanation)(5) By (EE) and (PE) follows the conclusion: if x is evidence, then x ispropositional.A more accurate restatement of Williamson’s argument should mention afurther aspect of Williamson’s position:(EVIDENCE) x is S’s evidence iff (i) x serves the central function ofevidence AND (ii) x is grasped/accessed by S.Where (i) is explained as follows:(CEF) x serves the central function of evidence iff x is an explanandum ofa hypothesis by IBE.In my previous formulations I presented (EE) in terms of what necessaryand sufficient conditions an item should satisfy to be counted as evidence.That is not completely exact. Instead I should have presented (EE) in terms4 There are two ways one could object to the (PE) claim. First, one could argue againstthe argument from the use of “that-clauses”, one way to do so would be to affirm that expla-nations without the use of the “that-clause” are genuine, not ill-formed explanations (Pryor(2007) considers one such tactic. Turri (2009) objects to positions which assume that proposi-tions can be epistemic reasons). A second objection might reject Williamson’s presuppositionthat facts are propositions (among classical proponents of the view that facts are not propo-sitions are Russell, Wittgenstein, Husserl). Thus x (a fact) can be explained without being aproposition itself.“09logins”2013/9/2page 350✐✐✐✐✐✐✐✐350 ARTURS LOGINSof necessary and sufficient conditions5 for an item playing the central evi-dential function. For reasons of simplicity, I assume the “short-cut”.6I propose now to turn to a critical examination of Williamson’s argument.3. Against Evidence as ExplanandumIn this section I raise an argument against the (PropE) argument. I reject the(EE) claim. I argue for this by giving two arguments — first I argue thatPremise 1 rests on a false presupposition, namely the idea that we are choos-ing between hypotheses (with regards to our evidence). Second, I claim thatthere is a more profound problem — the central function of evidence is notto be an explanandum of a hypothesis, but rather to explain (or cause) ahypothesis (belief).Before I continue, I propose, to be clear, recalling what it actually is weare talking about when we are talking about hypotheses here — we are infact talking about the content of our beliefs. Our ordinary epistemic practiceconcerns beliefs and their content. It is more natural to speak about thecontent of our doxastic attitudes and not hypotheses.Not choosing between hypothesesI propose that there is a serious problem with Williamson’s use of «choos-ing» between hypotheses as a central aspect of what evidence makes possible(premise 1). In our usual practice most of the time we don’t choose betweenhypotheses or propositions as potential contents of beliefs (or other doxas-tic states). To be able to choose between various entities implies that thereare those various entities, and that I have a kind of access to them (when Iam choosing between two kinds of apples in a supermarket I have a kind ofaccess to them, I see them, I can touch them, they are just there in front ofme, etc.). In case of potential contents of beliefs it is not clear what it wouldmean for there to be various accessed potential contents of beliefs betweenwhich I should choose: What is my access to them (if I don’t have an accessto them, how can I potentially choose between them)? Do I possess them(prior to acquisition of evidence)? Do I acquire them on the basis of evi-dence? If I don’t acquire them on the basis of evidence, then on the basis of5 Williamson doesn’t give his characterisation in terms of conditions, I use it in orderto simplify argumentation, I think that this use doesn’t change anything substantial for hisargument.6 I assume that this “short-cut” is not problematic for our purposes, as I leave to one sidethe question of grasping/accessing of evidence.“09logins”2013/9/2page 351✐✐✐✐✐✐✐✐ON WILLIAMSON’S ACCOUNT OF PROPOSITIONAL EVIDENCE 351what do I acquire them?7 If I do not hold them how can I choose betweenthem?.8 It seems natural to assume that I should at least grasp propositionsbetween which I am supposed to choose one (and that prior to choosing, oth-erwise my arrival to it is not a result of choice but an accidental guess). Andit seems also natural to assume that at least in some circumstances (most ofordinary situations where we discover things) we don’t possess contents ofour potential beliefs (= hypotheses), we don’t even grasp them.Therefore I claim that we don’t choose between hypotheses – potentialcontents of beliefs on the basis of evidence, because we don’t possess thesecontents before we come to know the evidence, and often even we couldnever possess or grasp those contents without the relevant evidence. Andeven if we come to believe all the relevant alternatives after acquiring knowl-edge of some piece of evidence, it doesn’t seem plausible that we wouldchoose between them. To choose between hypotheses (contents of beliefs)would mean that we are evaluating them, comparing them and then pickingout one which is the most appropriate (whatever it would mean). But thatdoesn’t seem to be the way in which we react to evidence. We acquire apiece of evidence, say a piece of strange information and posterior to it weformulate some surprising ideas which we are able to grasp only thanks tothe new evidence.Thus I conclude that it is not the case that we are undergoing IBE’s whenwe are faced with some evidence. Often we do not even consider otherpropositions but only the one which we form in the face of evidence. Instead,it seems that, given some background information in place, when we haveevidence e, we simply infer by default some other proposition p. Usually,having evidence does not imply choosing between hypotheses. Thus I rejectpremise 1 of the argument. And if premise 1 doesn’t hold then it createsproblems for the rest of the argument — premise 2 is no longer justified.However one could maintain that even if we should reject premise 1, onecould hold that it is central for a piece of evidence to be an explanandum ofa hypothesis. I now turn to this central claim.7 This causes a dilemma for Williamson: either these beliefs are already possessed, whichseems extremely implausible — how can we possess (psychologically) beliefs which explainsome evidence, before we come to know that evidence? Or on the other hand, we acquirethese beliefs. But then on the basis of what do we acquire them? It is rather common tospeak about epistemic reasons, on the basis of which our beliefs are acquired. But given thesimilarity between epistemic reasons and evidence, Williamson can’t motivate acquisition ofbeliefs on the basis of epistemic reasons because this would reverse his point of view.8 Another problem is that there are often cases where there are no competing hypotheses,but only one hypothesis.“09logins”2013/9/2page 352✐✐✐✐✐✐✐✐352 ARTURS LOGINSNot an explanandumMy second objection to Williamson’s argument concerns his key claim thatevidence is what a hypothesis explains. There are cases, I claim, where wehave evidence e in support of a proposition p, but p does not explain e for us.Consider the following case.9 Long time ago, Chevalier X had a love af-fair with a maid. That love affair made him mad. One day, in an excessof jealousy, he killed the maid when he saw her flirting with another man.Moved by grief, he had erected a tower of a specific height so that its shadowwould cover the spot where he first proclaimed his love to the maid every af-ternoon. Now, many years after the murder, Chevalier X tries to find onceagain the place where he proclaimed his love to the maid for the first time.He arrives near the tower in an afternoon and sees the shadow of the towercovering the precise spot. It seems that there is a a piece of evidence e thatChevalier possesses: “The shadow of the tower covers exactly this precisespot of the land”, and it seems that this piece of evidence e is evidence insupport of a proposition p, for him: “I’ve proclaimed my love to the maidfor the first time exactly here”. However, it doesn’t seem right to say that pexplains e for Chevalier X. The mere proposition p is not the explanation ofe. There is no direct and simple explanatory link between e and p. Hence,there are cases (I believe that the Chevalier case is not an isolated phenome-non) where someone can possess evidence in favour of a proposition withoutthat that proposition explains the piece of evidence.Now, the obvious reply that one could make against this objection, is toclaim that although p is not the explanation of e, it is nevertheless a partof the explanation of e. In order to possess the full explanation of e otherpropositions are also needed, such as “I had erected a tower of a specificheight”, “A n-meters high tower will produce a shadow of m-meters”, “Ihad intention to mark the spot with a shadow from a tower”, etc. Only awhole set of such propositions constitutes the explanation of e. However,importantly, e is what is (in part) explained by p.This reply is unsatisfactory, however. There are two problems with it.First, there seem to be no non ad-hoc (or non pragmatic10 ) way of distin-guishing p from other propositions among the full explanation of e. But this9 Adapted from van Fraassen 1980.10 One could follow van Fraassen 1980 and endorse the claim that explanations are prag-matically determined. And then, accept that what evidence is, after all, is also determinedin part by pragmatic factors (in virtue of its being an explanandum). This move is not avail-able to Williamson, however. Since he explicitly (Williamson 2005) denies that pragmaticalfactors determine knowledge possession. And according to Williamson, the set of knownpropositions by a subject S just is the set of evidence that S possesses. Hence, if Williamsonallowed that evidence is pragmatically determined, then he also had to allow that knowledgeis pragmatically determined.“09logins”2013/9/2page 353✐✐✐✐✐✐✐✐ON WILLIAMSON’S ACCOUNT OF PROPOSITIONAL EVIDENCE 353is problematic, since p seems to enjoy a special status with regards to e. Itseems that e is evidence for p, for Chevalier, it is not evidence for someother proposition for him, such as p′: “A n-meters high tower will producea shadow of m-meters”, or if it is, then only secondarily. One cannot, forinstance, appeal to probabilities, in order to explain this special status of pwith regards to e, since, p′ conditional on e does not seem to be less prob-able with regards to unconditional p′, than is p conditional on e comparedto unconditional p. Hence, it seems there is no way to account, within thisframework, for the fact that e is evidence for p, rather than for p′, for Cheva-lier (or that, primarily, e is evidence for p and not for other propositions, forChevalier). Second problem is even more radical one. On pain of having anad hoc approach, everything within the full causal history of e, going backto the Big Bang, should be included as a part of the full explanation of e. Butwe surely don’t want to define evidence e as what is explained by the fullcausal history of e, going back to the Big Bang. But then, if we don’t havetheoretically satisfactory way to identify a particular partial explanation andwe don’t want the whole set of the full explanation to be what explains apiece of evidence e, then we have to conclude that evidence is not what isexplained by a hypothesis.On the contrary, it is natural to think that evidence just is what enables usto form a belief, or to make inferences. There is a sense in which a beliefor positioning a hypothesis is a response to evidence. Sherlock Holmes,for example, gathers evidence before forming a hypothesis. And when asufficient amount of evidence is gathered he forms a hypothesis. Evidenceis what enables him to state an explanatory hypothesis.Thus I conclude that (EE) does not state the central function of evidence.Evidence is not essentially an explanandum for a hypothesis.If (EE) doesn’t hold then the (PropE) argument doesn’t hold. (EE) is false.Thus the (PropE) argument doesn’t hold. It doesn’t show that all evidence isnecessarily propositional.ConclusionI have considered Williamson’s argument for the claim that all evidence ispropositional. I have claimed that his argument doesn’t hold, because twoof its premises are not true. I have not claimed, however, that there is non-propositional evidence. There might be other good arguments in favour ofthe propositionality of evidence. This larger question is left for another in-vestigation.University of Geneva, Episteme, SwitzerlandE-mail: Arturs.Logins@unige.ch“09logins”2013/9/2page 354✐✐✐✐✐✐✐✐354 ARTURS LOGINSREFERENCESPryor, James (2007). ‘Reasons and That-clauses’, Philosophical Issues,vol. 17.Turri, John (2009). ‘The Ontology of Epistemic Reasons’, Noûs, 43.Van Fraassen, Bas C. (1980). The Scientific Image. Oxford University Press.Williamson, Timothy (2000). Knowledge and its Limits, New York, OxfordUniversity Press.Williamson, Timothy (2005). Contextualism, subject-sensitive invariantismand knowledge of knowledge. Philosophical Quarterly 55 (219):213–235.

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