The Unthinkable, Might It Be? A basic intuition about epistemic possibility is the following: It might be that p iff it is open whether p. The standard way of cashing out this intuition is: It might be that p iff it is reconcilable with one's informational state that p. However, there are certain examples which point to a lacuna in this conception. They indicate that epistemic possibility is restricted to what one can conceive as an alternative, what one can have a cognitive attitude to. A basic intuition about epistemic possibility is the following one: (Open) It might be that p iff it is open whether P. There is a standard way of cashing out this intuition: (Ignorance) It might be for S that P iff S does not know that ~P. Many sophisticated accounts of epistemic possibility take their inspiration from (Ignorance), for instance Keith DeRose's: S's assertion, 'It is possible that Pind' is true if and only if (i): No member of the relevant community knows that P is false, and (ii) There is no relevant way by which members of the relevant community can come to know that P is false, where both the issue of who is and who is not a member of the relevant community and what is and what is not a relevant way of coming to know are very flexible matters that vary according to the context of the utterance of the epistemic modal statement...(DeRose 1999, 398) 2 Roughly, it might be respectively is epistemically possible that P iff the relevant community does not possess a significant way of settling that P is false. Further sophisticated attempts of explicating the epistemic 'might' also draw on (Ignorance). The lay of the land: Epistemic modals quantify over possibilities compatible with what is known-more generally, those possibilities compatible with the evidence available or the information at hand in a context. (von Fintel and Gillies 2008, 78, cf. Yalcin 2007)1 In my view, an example forwarded by Michael Huemer testifies to a blindspot in this approach. (Open) can be understood by what one is not in a position to exclude. But it can also be understood in a more positive manner: what one can have an attitude towards, what one is in a position to consider as an alternative. In order to consider something as an alternative, one must be in a position to have a cognitive attitude towards it. In order for something to be open for someone, one must be in a position to consider it without being in a position to rule it out. Only the thinkable is epistemically possible. If this reading of (Open) is taken seriously, the main thrust of the standard analysis can be reconciled with Huemer's counterexamples. Huemer's crucial examples are these: Rigel 7: 1 There are heretics: Benjamin Schnieder advocates expressivism concerning epistemic modals (Schnieder 2010). 3 Rigel 7 is the seventh planet in the Rigel star system. Sam, however, knows nothing of Rigel and consequently has no thoughts about Rigel or any of its planets. Sam looks at his couch in normal conditions and sees nothing on it. Mary (who happens to know of Rigel 7) says: 'For all Sam knows, Rigel 7 might be on the couch'. Unconscious Sam: Sam is currently unconscious. Mary says: 'It is epistemically possible for Sam that he is now conscious. In fact, it is epistemically impossible for him that he is unconscious'.(Huemer 2007, 121-122) Note that Huemer has Mary give a verdict about what is epistemically possible for Sam. In doing so, Huemer circumvents the difficulties with an epistemic possibility tout court that is not an epistemic possibility for someone which a good deal of recent literature focuses on: ...all the trouble starts with simple, unmodified must/might claims. No speaker will feel pressured to retract a statement like (38) 'As far as I know for the moment, George might be in Boston.' ... If the context does not make it clear which interpretation is intended, it isn't clear what precisely the value of the modal base is. We would like to offer the metaphor of 'a cloud of admissible contexts' with respect to which the sentence might be interpreted. (von Fintel and Gillies 2008, 96) While 'might' tout court seems sensitive to circumstances of utterance and assessment, 'for all S knows' is bound to a certain subject S at a certain time point and her state of information. I will join Huemer in limiting my perspective. One caveat will emerge later. Sometimes even 'for all S knows'-claims might be in a certain way assessor-relative. 4 Huemer takes his examples to be irreconcilable with (Ignorance). Since I have encountered people who deem (Ignorance) to withstand Huemer's counterexamples, I feel uneasy in how far the latter provide good evidence against (Ignorance). Hence I want to claim that there are two alternatives. We can either retain (Ignorance) and bluntly reject Huemer's alleged counterevidence. So after all, the unthinkable might be. Or we accept that Huemer uncovers that there is something wrong with (Ignorance). The considerations to follow are confined to the latter alternative. I agree with Huemer. However, I disagree about the diagnoses of the Unconscious Sam and the Rigel 7 case. My preferred diagnosis is that the unthinkable is not epistemically possible. I want to launch a definition of epistemic possibility which conforms to this constraint. I now want to criticize Huemer's own handling of his examples. He claims that only the following gerrymandered analysis can accommodate them: D8 P is epistemically possible for S=It is not the case that P is epistemically impossible for S. P is epistemically impossible for S = a. P is false; b. S has justification for ~P adequate for dismissing P; and c. S's justification for ~P is Gettier-proof.(Huemer 2007, 135) I follow Huemer in replacing knowledge that ~P as a criterion by something like being in a position to rule out P or having evidence sufficient for ruling out P. But I want to remain deliberately vague on that. In the case of Unconscious Sam, Huemer calls bizarre what Mary says. Here is why: 5 In Unconscious Sam, Sam lacks justification for the claim that he is conscious, because (among other things) he does not presently have any evidence such that, if he were to consider whether it supports the claim that he is conscious, it would be obvious to him that it does.(Huemer 2007, 135) Huemer's point must be this: Mary maintains it to be epistemically impossible for Sam that he is unconscious. Yet according to D8, it is not epistemically impossible that Sam is unconscious. For neither is it false that he is unconscious, nor does he have evidence that he is conscious. Hence it is possible that he is unconscious. Now the same holds for Sam being conscious. According to Huemer's definition, it is epistemically possible that Sam is conscious. For Sam does not have evidence that he is unconscious. Yet there is another explanation why what Mary says sounds bizarre: It is wrong that Sam's being conscious is epistemically possible for unconscious Sam. Consider Mary's claims separately: It is epistemically possible for unconscious Sam that he be conscious. It is epistemically impossible for unconscious Sam that he be unconscious. If there is any claim that sounds bizarre to me, it is the former. But Huemer rules out the latter and not the former. In contrast, I want to rule out the former. More precisely, I claim that it is neither possible for Sam that he is conscious nor that he is unconscious. Let me elaborate my intuition: Being conscious or not being conscious fail to be epistemic possibilities for unconscious Sam as he is not in a position to have a cognitive attitude towards either of these alternatives. For since he is unconscious, he neither can form an occurrent thought about them, nor does he have a suitable dispositional attitude like belief or 6 knowledge towards them.2 To be sure, there may well be epistemic possibilities for Sam while he is unconscious. For surely P may be possible for unconscious Sam if he rationally believes or at least if he knows that P. Knowledge and belief are dispositional. Hence unconscious Sam can have beliefs and knowledge. But whereas Sam may be claimed to know that 2+2=4 while unconscious, he cannot be claimed to believe that he is conscious or that he is unconscious: the former because the belief that he is conscious he forms while he is conscious is restricted to the time span of being conscious; the latter because he never forms the belief that he is unconscious in a rational way. Huemer's main evidence against (Ignorance) is the Rigel 7 case: Huemer claims that it is not possible for Sam that Rigel 7 is on the couch as Sam has evidence to the contrary. (Ignorance) mishandles this case in yielding the following analysis: Since Sam does not have a belief about Rigel 7, he does not know that Rigel 7 is not on the couch. Hence it is possible that Rigel 7 is on the couch (cf. Huemer 2007, 124-5). The example calls for a more differentiated treatment. Sam has visual evidence that Rigel 7 is not on the couch. But Sam has no idea what 'Rigel 7' stands for. What if Rigel 7 is a dust particle? Sam does not have visual evidence that there is no dust particle on the couch. We must modify Huemer's example somewhat in order to consider two alternatives: 1.1) Sam has evidence (as much as knowledge requires) that nothing is on the couch, including dust particles, atoms and so on. 1.2) He does not have such evidence. 2 One may interpret being in a position to form a thought as a dispositional attitude, too. Nevertheless, I am confident that my proposal could be modified such as to cope with this view. 7 There is a further distinction to be made. Huemer does not take into account the eventuality that Sam has Rigel 7 thoughts by virtue of deferring to his fellows' use of 'Rigel 7'. 2.1) Sam is not in a position to have Rigel 7 thoughts. 2.2) Sam is in a position to have Rigel 7 thoughts as he can defer to his fellows' use of 'Rigel 7'. To Huemer, distinction 2 does not make a difference. If (1.1), it is epistemically impossible for Sam that Rigel 7 is on the couch as he has evidence to the contrary (see my schema below). In contrast, it is epistemically possible for Sam that Rigel 7 is not on the couch. If (1.2) is assumed, it is as well epistemically possible that Rigel 7 is on the couch as that Rigel 7 is not. For Sam does not have evidence which allows to rule out one of these alternatives. In my view, distinction 2 does make a difference. Given (2.1), I deem it neither epistemically possible for Sam that Rigel 7 is on the couch nor that Rigel 7 is not, the reason being that Sam lacks the conceptual resources to form either thought. Given (2.2), I concur with Huemer's results. Alternative (2.2) allows an explanation why Mary's verdict does not sound as bad as Huemer supposes. When we consider Mary's verdict, we tend to see Sam as deferring to Mary's use of language. For instance, when Mary asks him whether he can exclude that Rigel 7 is on the couch, it is quite natural for him to reply (given (1.2)): 'Rigel 7 might well be on the couch, for all I know, because I do not know what that means.' In the first part of his statement, Sam defers to Mary's use of language. He presupposes for Gricean reasons that 'Rigel 7 is on the couch' is a well-formed assertoric sentence the meaning of which is known to Mary. In a similar vein, we take Mary as presupposing that 8 Sam defers to her language use when she deems it epistemically possible for him that Rigel 7 is on the couch. The upshot of my discussing Rigel 7 is the following: I agree with Huemer that given (1.1) and (2.1), (Ignorance) yields the wrong result. It is not epistemically possible for Sam that Rigel 7 is on the couch (and pace Huemer it is not possible either that Rigel 7 is not). Hence (Ignorance) must be modified. I disagree with (Ignorance) and Huemer in holding that given (1.2) and (2.1), it is impossible for Sam that Rigel 7 is on the couch. Hence I also reject Huemer's analysis. There is a more intriguing alternative explanation of our tendency to bring in Mary's possession of Rigel 7-thoughts: One lesson of current debate is that 'might' is very vague. We may resolve this vagueness in many ways. Some of them bring in the perspective of the assessor. Consider the following example: Pascal and Mordecai are playing Mastermind. After some rounds where Mordecai gives Pascal hints about the solution, Pascal says (15) There might be two reds. Mordecai, knowing the solution, has a range of possible responses: (16) a. That's right. There might be. b. That's right. There are. c. That's wrong. There can't be. d. That's wrong. There aren't. (von Fintel and Gillies 2008, 83) 9 To go into more detail: Assume that there are two reds. Then Mordecai has alternatives (16a) – (16b).3 In order to endorse (16b), he must take into account what he knows. Assume that there aren't two reds. Then Mordecai has alternatives (16a), (b), (c). In order to endorse (16 a), he must take the epistemic stance of Pascal. In order to endorse (16c) or (d), he must take into account what he knows. This shows how extremely flexible 'might' is regarding the epistemic outlook from which it is evaluated. 'Might as far as Pascal knows' is less flexible. But I suppose that even in this case, there is a certain assessor-relativity. Even if Sam does not defer to Mary's use of language, Mary may. Perhaps assessor-relativity comes into play when Mary (not Sam) assesses what is epistemically possible for Sam.4 She just uses her linguistic and conceptual competence to determine what can be thought of and combines it with Sam's epistemic outlook. Given (1.1), it is epistemically impossible for Sam that Rigel 7 is on the couch. Given (1.2), it is possible. But she may as well stick to Sam's conceptual and linguistic resources and maintain that Rigel 7 being on the couch is not epistemically possible for Sam even if he has no evidence to the contrary given (1.2). Yet it would be absurd if Mary brought in her epistemic outlook in the Unconscious Sam case. Hence in assessing 'possible for' the assessor can only bring in her linguistic and conceptual competence, not her epistemic outlook. Here is a schema of the results regarding the claim is that it might be that P (To Sam, Rigel 7 might be on the couch): Given 2.1 (Sam is not in a position to have Rigel 7 – thoughts) 3 Since (16a) is weaker than what Mordecai could say, Gricean reasons might require him to take Pascal's epistemic stance when professing it. 4 On varieties of relativism cf. McFarlane (2003), Egan (2007), Weatherson (2009, 339-342). 10 1.1 (evidence that ∼P) 1.2 (no evidence) (Ignorance) true true Huemer false true My proposal false false My proposal modulo assessor relativity false true Given 2.2 (Sam is in a position to have Rigel 7 thoughts) (Ignorance) true true Huemer false true My proposal false true My proposal modulo assessor relativity - - Let us disregard assessor-relativity for a moment. In order to accommodate the intuitions I have presented, I propose the following analysis for an assessor A and a subject S: (Attitude): To A, it is epistemically possible for S at t that P iff a) S cannot rule out P and b) S is in a position at t to have a cognitive attitude towards P. S is in a position at t to have a cognitive attitude towards P if (i) S has some dispositional propositional attitude towards P at t like knowing or believing that P which one can have while being unconscious, or 11 (ii) a P-thought is readily available to S at t in the way thoughts are available to normal conscious thinking subjects possessing the conceptual resources to have a P-thought. Since this analysis allows to explain what is special about Huemer's crucial examples Unconscious Sam and Rigel 7, it is supported by them (provided one finds them compelling). A further advantage is that it allows to deal with an intuitive uncertainty. I feel uncertain how to deal with thoughts one cannot entertain as one is not in a position to entertain them. On the one hand, at first glance what one cannot rule out seems epistemically possible. But on the other hand I reckon epistemic possibilities to be thought options available to the epistemic subject. The epistemic subject should be in a position to take them into account as this is the pragmatic import of epistemic possibilities. (Attitude) allows to explain this uncertainty: On the one hand, there is the criterion (a) that one cannot rule out P. However, this criterion, taken in isolation, does not pay due respect to the question whether something is an option available to the epistemic subject. On the other hand, there is the strong additional criterion (b) I propose. Cases which are not ruled out by the first but by the second criterion so to speak form disputed territory. At first glance, we are not completely sure how to judge them in terms of epistemic possibility. The reason is, I surmise, that without sufficient reflection on such cases, we tend to focus on the first criterion. But upon reflection on cases as discussed by Huemer, the second criterion (b) appears indispensable, too. This diagnosis allows to explain away the intuitive aversion to Huemer's evidence I mentioned at the beginning.5 5 How does this analysis square with Huemer's further evidence? (i) If S knows that P, then it is not epistemically possible for S that ~P. (ii) If it is impossible that P, then ~P. (iii) If it is possible that P, and P entails Q, then it is possible that Q.(Huemer 2007, 120) 12 I want to finish with an assessor-relative modification of (attitude). It allows to further explain the above uncertainty with respect to criterion b). This modification pays due respect to the assessor A (Mary in the Rigel 7 case) bringing in her linguistic and conceptual resources. (Attitude ): To A, it is epistemically possible for S at t that P iff b) S cannot rule out P and ba) S is in a position at t to have a cognitive attitude towards P. or Huemer accepts (i) and (ii) and rejects (iii). I disagree only in so far as I regard (ii) as in need of further qualification. (i) directly follows from my analysis. (ii) If I am right that there are cases in which both P and ~P are epistemically impossible for a subject, then (ii) must be rejected, because it commits us to the contradiction P & ~P in such cases. However, I want to claim that my analysis allows a more differentiated treatment of (ii). If it is not possible that P, this may be due a) to S's being able to rule out P or b) due to S's not being in a position to form a cognitive attitude towards P. Since we tend to neglect (b)-cases, we tend to (ii). But upon reflection, I suggest that instead of (ii), we tend to (ii*) If it is not possible for S that P and S is in a position to have a cognitive attitude towards P, ~P. 13 bb) S were in a position at t to have such an attitude had S A's linguistic and conceptual resources. The uncertainty in our verdicts can to a certain extent also be explained by the vagueness of 'might'. It leaves open whether to bring in the resources of S or A, whether (attitude) and (attitude ) is the intended analysis. Consequently, when we drop the constraint of 'possible for S' and proceed to 'might' tout court, 'might' becomes even more vague than envisaged in current debate. There are many admissible precisifications. Assume that Sam has no evidence that Rigel 7 is not on the couch (1.2). Nevertheless Mary may say that Rigel 7 might not be on the couch. Then she just constrains 'might' by what Sam can have an attitude to. But she may also say that Rigel 7 might be on the couch. Then she constrains 'might' by Sam's evidence and her conceptual and linguistic resources. Egan, A. (2007). Epistemic Modals, Relativism, and Assertion. Philosophical Studies, 133, 1– 22. Huemer, M. (2007). Epistemic Possibility. Synthese, 156, 119–142. McFarlane J. (2003). Future Contingents and Relative Truth. The Philosophical Quarterly, 53, 321–336. DeRose, K. (1999). Can it be that it would have been even though it might not have been?. Philosophical Perspectives, 13, 385-415. 14 Schnieder, B. (2010). Expressivism concerning Epistemic Modals. The Philosophical Quarterly, 60, 601-615. Von Fintel, K., Gillies, A. S. (2008). CIA Leaks. The Philosophical Review, 117, 77-98. Yalcin, S. (2007). Epistemic Modals. Mind, 116, 983–1026. Weatherson, B. (2009). Conditionals and Indexical Relativism. Synthese, 166, 333–357.