tag:blogger.com,1999:blog-6642011.post5853816508282560351..comments2023-10-29T10:32:36.914-04:00Comments on Philosophy, et cetera: The Kripke-Harman Dogmatism ParadoxRichard Y Chappellhttp://www.blogger.com/profile/16725218276285291235noreply@blogger.comBlogger10125tag:blogger.com,1999:blog-6642011.post-81637345451274756082011-12-12T13:48:48.413-05:002011-12-12T13:48:48.413-05:00I'm sympathetic to the view that we generally ...I'm sympathetic to the view that we generally do better to talk in terms of rational credence rather than knowledge. Still, the latter needn't be problematic -- so long as we remember that, as fallibilists, we can't move from "S knows that h" to "S should be absolutely certain that h".Richard Y Chappellhttps://www.blogger.com/profile/16725218276285291235noreply@blogger.comtag:blogger.com,1999:blog-6642011.post-18694033422959678062011-10-20T20:50:56.362-04:002011-10-20T20:50:56.362-04:00This paradox relates to a question I had in my the...This paradox relates to a question I had in my theory of knowledge course that didn't get answered satisfactorily. Maybe someone can answer it here?<br /><br />It seems like the paradox is based on the view that as soon as you have evidence that indicates that h has a high chance of being true, and you believe h to be true, you are compelled to say that you 'know' h to be true, and therefore must act as if there is a 100% chance of h being true. And since you apparently believe that h has 100% chance of being true you of course disregard evidence to the contrary.<br /><br />This idea that having a justified belief means you must act as if it is absolutely certainly true is what came up in my philosophy of knowledge class. I still don't get it, it seems absurd. Surely, when you are faced with evidence that gives 90% confidence that h is true, the correct attitude is that h has a 90% chance of being true, rather than that H has a 100% chance of being true? And if you accept this fairly obvious fact, surely there's no paradox here!Anonymousnoreply@blogger.comtag:blogger.com,1999:blog-6642011.post-88025623709702024492011-10-12T13:41:16.841-04:002011-10-12T13:41:16.841-04:00Tony - Note that sometimes we rationally ought to ...Tony - Note that sometimes we rationally ought to believe falsehoods, if the best available evidence happens to be (unbeknownst to us) misleading. Just because we've been misled doesn't mean that we "should have been more dogmatic", if by that you mean the "should" of epistemic rationality. What we should believe is whatever is best supported by our evidence. If the more dogmatic person ends up believing the truth, that's just because they got lucky on this occasion, not because they're believing as they ought.<br /><br />Regarding your later question: I was thinking that at time t0 you <i>are</i> justified in believing (falsely) that there's no sufficiently strong evidence against h, which why you're also justified in believing (truly) that h is true.<br /><br />Then, when you then acquire the new evidence e at t1, you're no longer justified in either belief. The factivity of knowledge doesn't suffice to prevent later evidence from undermining the justification for your earlier knowledge-constituting belief, and hence (because knowledge requires justification in addition to truth) causing this true belief to no longer qualify as knowledge.Richard Y Chappellhttps://www.blogger.com/profile/16725218276285291235noreply@blogger.comtag:blogger.com,1999:blog-6642011.post-72250678964881314412011-10-12T13:30:08.317-04:002011-10-12T13:30:08.317-04:00I don’t think distinguishing what you know at vari...I don’t think distinguishing what you know at various times works. At t0 I may not know p but at t1 I do know p works fine. But it’s a lot more difficult to know h at t0 and then stop knowing it later on, under factivity of knowledge. “If you initially know that h is true, but later uncover some evidence e that would undermine belief in h, then you can't appeal to h as grounds for disregarding e.” But you did not initially know h as, if h were true, no non-misleading evidence could arise.<br /><br />However I don’t think the paradox “gets going” unless we make explicit a denial of scepticism and factivity of knowledge.<br /><br />“<b>If you initially know that h is true, but later uncover some evidence e that would undermine belief in h, then you can't appeal to h as grounds for disregarding e.</b>”<br /><br />If knowledge is factive then if you know at t0 that h is true then h is true. If true then any apparent evidence against h <i>is</i> misleading. If some later evidence undermines your belief in h then you have been mislead and should have been more dogmatic.<br /><br />There doesn’t seem to be any paradox here.<br /><br />Perhaps the problem is that:<br /><br />1. “<b>You’re only justified in believing that "any evidence against h is misleading" insofar as you're justified in believing that there <i>isn't</i> any such (sufficiently weighty) evidence against h.</b>”<br /><br />and<br /><br />2. you are <i>not</i> justified in believing that there isn’t any such evidence against h?<br /><br />If you aren’t so justified then you are not justified in believing h to be true. h entails that there is no non-misleading evidence against h and you are not justified in believing that. You may be justified in believing that <i>some</i> of h is true, that h is <i>likely</i> to be true, that h is way-the-best-explanation for the current e etc. but not that h is true.<br /><br />But this is not sufficient for knowledge, if knowledge is factive. If “knowledge” can be something like “espousing the best hypothesis” or “reasonably accepting a hypothesis that has more verisimilitude than it’s current rivals” rather than “justified/warranted true belief” then we can (and do) have oodles of knowledge. h doesn’t need to be true, we don’t even need to believe that h is true: just that h is the best available to us right now. h no longer entails that there will be no non-misleading evidence against h and the paradox disappears.<br /><br />The paradox also disappears with knowledge-scepticism. “If we knew h then we could ignore later e” is true by that falsity of the antecedent thing you mentioned.Tonynoreply@blogger.comtag:blogger.com,1999:blog-6642011.post-6585555132786175812011-10-09T07:14:20.257-04:002011-10-09T07:14:20.257-04:00Hi Richard,
Yep, I agree with all that! (I wasn&#...Hi Richard,<br /><br />Yep, I agree with all that! (I wasn't trying to resuscitate the paradox, by the way - just to improve your solution.)Tristan Hazehttps://www.blogger.com/profile/18008340011384137776noreply@blogger.comtag:blogger.com,1999:blog-6642011.post-64075616369082831032011-10-08T11:04:47.181-04:002011-10-08T11:04:47.181-04:00Hi Tristan, that sounds ok to me, as it means that...Hi Tristan, that sounds ok to me, as it means that your context-specific indicative conditional will be undermined by e in much the same way that I suggested a material conditional would.<br /><br />You've basically suggested a way that even the indicative conditional could be "vacuously true", i.e. compatible with e being accurate evidence in the closest possible world where e obtains. You're just ruling out consideration of such worlds by contextual fiat. But if the agent believes e to be accurate evidence in the closest possible world where it obtains, and then they learn that it actually obtains, this plausibly undermines their basis for believing the conditional -- since they only believed it because they took it to be vacuously true. They had no basis for thinking it to be <i>non-vacuously</i> true, which is what the paradox would require.Richard Y Chappellhttps://www.blogger.com/profile/16725218276285291235noreply@blogger.comtag:blogger.com,1999:blog-6642011.post-69027610811782950582011-10-08T07:14:53.700-04:002011-10-08T07:14:53.700-04:00(I realize, of course, that Lewis himself did not ...(I realize, of course, that Lewis himself did not take a Stalnaker-Lewis style approach to indicative conditionals.)Tristan Hazehttps://www.blogger.com/profile/18008340011384137776noreply@blogger.comtag:blogger.com,1999:blog-6642011.post-8723099850493401512011-10-08T07:10:42.544-04:002011-10-08T07:10:42.544-04:00I think it is possible to resist the idea that ...I think it is possible to resist the idea that 'If e obtains then e is misleading evidence' can only come out true when read as a material conditional.<br /><br />Consider a Stalnaker-Lewis style approach to indicative conditionals, employing epistemically possible scenarios or worlds (rather than subjunctively/metaphysically possible worlds). The set of scenarios to be considered in evaluation may vary contextually. <br /><br />So in one context, where one wishes to consider all scenarios not ruled out by current knowledge, and <i>h</i> is taken to be known, the conditional will come out true. In a context where <i>h</i> is being called into question, the conditional may not come out true.<br /><br />Obviously, this suggestion is incompatible with certain views of indicative conditionals, but it seems plausible to me. What do you think?Tristan Hazehttps://www.blogger.com/profile/18008340011384137776noreply@blogger.comtag:blogger.com,1999:blog-6642011.post-76773513349474892642011-10-06T17:58:29.343-04:002011-10-06T17:58:29.343-04:00Hmm, that's interesting. I wonder then how we...Hmm, that's interesting. I wonder then how we are to explain the epistemic significance of actually coming to <i>possess</i> such antecedently predictable evidence. Perhaps there's an implicit assumption that the evidence we come to possess is (something close to) randomly sampled from all the evidence that's out there? Say if God tells you he's identified for you the strongest evidence against p, without regard for whether there's comparably strong further evidence for p, perhaps coming to possess this new evidence <i>in this way</i> would no longer undercut your knowledge? (After all, if you already expected that there was <i>some</i> evidence roughly this weighty out there somewhere, merely being told <i>what it was</i> doesn't seem like it should change things.)<br /><br />But whatever the details, so long as we have some story to tell about how <i>ordinarily</i> acquiring new evidence can defeat knowledge, then it seems like we should be able to run some version of my above story along with it. (Perhaps shifting to a more specific conditional, e.g. "If I will come to possess e in the ordinary way, then e is misleading." Justified at t0 as a material conditional, but again only because you expect the antecedent to be false.)Richard Y Chappellhttps://www.blogger.com/profile/16725218276285291235noreply@blogger.comtag:blogger.com,1999:blog-6642011.post-91127578723621077082011-10-06T17:29:52.865-04:002011-10-06T17:29:52.865-04:00I'm not sure it's so simple as that. In ty...I'm not sure it's so simple as that. In typical cases, I think there's lots and lots of unpossessed evidence on both sides. I know that p: some philosophers are coming to dinner at my apartment later today. So I know that any evidence against this proposition is misleading evidence. Furthermore, I am confident that there is some such evidence -- perhaps if I had it, I'd lose my knowledge. I don't know which such potential evidence is actual, of course, but I'm sure that some is.<br /><br />For example, the disjunction of ~p and any extremely surprising truth would be pretty good evidence against p. I'm confident there are such propositions.Jonathan Jenkins Ichikawahttps://www.blogger.com/profile/05260245860017778409noreply@blogger.com