Knowing an Answer and Knowing Who

In the thread below on knowing who, David Braun suggests that statements like the following sound contradictory.

‘Zaphod Beeblebrox kissed that guy’ is an answer to the question ‘Who did Zaphod Beeblebrox kiss?’, and B knows that Zaphod Beeblebrox kissed that guy, and so she knows an answer to the question of who Zaphod Beeblebrox kissed, but she does not know who Zaphod Beeblebrox kissed.

I think this sounds fine in some cases, or at least if it doesn’t this tells us something about what counts as an answer to a question.

Let’s get some background. As President of the galaxy, Zaphod legalised gay marriage, so ‘that guy’ denotes in the context his husband. Last night Zaphod was at a party where by all accounts he kissed celebrities from every major star system. He also gave that guy a goodnight kiss. The identities of the celebrities are a mystery. B knows that Zaphod kissed his husband, but not the mysterious celebrities.

Now what about David’s sentence? I think B doesn’t know who Zaphod kissed. She does know that he kissed that guy. Is ‘Zaphod kissed that guy’ an answer to the question of who Zaphod kissed? I’m half-tempted to say it is, so here’s a case where David’s ‘contradictory’ sounding sentence is true. But maybe I’m missing something crucial about the semantics of plurals and/or questions here.

Knowledge and False Beliefs

I was rereading Bill Lycan’s paper On the Gettier Problem Problem and I noticed a couple of odd things about his view that knowledge justified true belief with ‘no false assumptions’. I think Lycan does a pretty good job in arguing that the cases that were traditionally thought to pose a problem for this view do not really pose such a problem. But still there are three kinds of cases where I think something needs to be said. Continue reading “Knowledge and False Beliefs”

Papers Blog

There’s a new papers blog entry up.

As you can probably see from the gap between entries these days, my enthusiasm for the papers blog project, and my time available for doing it, are diminishing somewhat. (The fall off in entries has led to a fall off in hits – from 12000 unique visitors in April down to little over 8000 this month.) Now that everyone in philosophy has papers online, keeping track of all the address changes, clawing through all the false positives (people who keep things like office hours, or lists of talks in their departments etc on their papers page have pages that update all the time without much interest), finding out whether something is a paper or basically a blog post to a non-blog, separating out the philosophy papers from the non-philosophy papers on sites that have both, etc takes more time than I can really spare. And I have another project that I’ll be launching soon that will take up a fair bit of time. So I suspect that I’ll basically give it all up fairly soon.

On the other hand, the procedures for running the site are now fairly well in place. Anyone who is interested in taking it over, either at or at their own address, should leave a note in the comments here. I think I could probably pass on the knowledge I’ve gained from doing this fairly quickly so a new person could hit the ground running. Possibly someone who is better at this kind of thing than me could arrange for grant money to keep the site running with the administrator getting paid. With an hour a day it could be a really very effective site, so the grants in question needn’t be more than a few thousand dollars a year.

i’s dotted, t’s crossed

In my paper on pragmatics and justification, I make a big song and dance about the fact that by definition of belief in probabilistic terms allows for multi-premise closure, or at least a plausible version of it. More precisely, it says the coherent agent believes the conjunction of any two things she believes, if all three are salient. What I didn’t go back and check, because I could hardly believe it could be an issue, is whether we still have single-premise closure. And, to my horror, it turns out that in the theory as presented there, we don’t. But there’s a small fix that solves the problem it turns out. Because the symbols get rather messy in HTML, I put the write up of the problem and the fix into a PDF file below.

CCNCP is my new and uncatchy shorthand for Conditionalisation Changes No Conditional Preferences, which is the full name for the theory, though sadly not quite a full description of it!

Knowledge and Justification

In a forthcoming paper I argue that the reasons adduced by various authors (e.g. Jeremy Fantl and Matthew McGrath, Jason Stanley, and John Hawthorne) don’t give us reason to think that there is a need for a pragmatic component in our theory of justified belief. My view was that the cases they developed showed we needed a pragmatic component to our analysis of belief, as functionalists have been saying for a few years now, but the justified part of justified belief could be left entirely free of pragmatic concerns. When I wrote the paper I thought that the same would be true for our theory of knowledge, though I was a little worried about whether the right account of defeaters would be pragmatically neutral. I think the paper is cautious enough to not say that the same is true of knowledge, though it probably does implicate that.

Anyway, now that I’m trying to write up the extension of my theory of justified belief to a theory of knowledge, it seems I should have been more worried. The impact of practical considerations seems to be very different on knowledge and on justification in a couple of cases, both of which I was aware of when I wrote the earlier paper. The cases are one that Jason calls ‘Ignorant High Stakes’ and a case I discussed of a gamble where the agent has unreasonable beliefs about the cost of losing the bet. Continue reading “Knowledge and Justification”

Gettier and Safety

It’s often claimed that there is a close connection between the tacit reasoning we use in Gettier cases and the safety constraint. Here, for instance, is John Hawthorne from page 54 of Knowledge and Lotteries.

Insofar as we withhold knowledge in Gettier cases, it seems likely that ‘ease
of mistake’ reasoning is at work, since there is a very natural sense in such cases, in which the true believer forms a belief in a way that could very easily have delivered error.

I suspect that’s not true. I don’t mean to pick on John here, I think it’s a widespread view in epistemology. But it’s false.

Here’s what I’ll argue. (Step One) There are some Gettier cases where the resultant belief satisfies every safety condition we could want. In those cases we don’t tend to assign knowledge to the agent. (Step Two) The reasoning we use in those cases is the same as the reasoning we use in all Gettier cases. So, the reasoning we use in Gettier cases is not safety reasoning. Continue reading “Gettier and Safety”

A Puzzle for Subject-Sensitive Invariantism

When I was at Rutgers the weekend before last I was talking to Sam Cumming about, among other things, subject-senstive invariantism. Sam mentioned that there seem to be some interesting difficulties in generalising SSI so it is a theory of group knowledge as well as individual knowledge. These all seemed like excellent concerns, and I didn’t have much to say about them. (On my theory the problem of explaining what group knowledge is ‘reduces’ to the problem of explaining what group preferences are, which may not be progress.) I’ll leave Sam to say what the problems he’s noticed are, but I thought I’d note here that one of them seems to be a complication even for people who merely care about individual knowledge. Here’s the problem.

S has a lot of evidence that p, and p is in fact true. She doesn’t think much turns on p, so she accepts p. We might imagine that were p of little importance to her, she’d actually know that p. But it turns out that p is really important to her, so by SSI standards she doesn’t know that p.

S knows that p entails q, and she infers q from p. All her evidence for p is evidence that q. And q really isn’t important to her, or at least that important. (Presumably q is evidence that p, so q is of some importance, but not that important.) Could she thereby come to know that q? Continue reading “A Puzzle for Subject-Sensitive Invariantism”

A Cheer for Contextualism

Ishani and I were talking about who various people here in Canberra are, and we noticed that the following conversation seems coherent, and in an environment where the folk are ignorant of Zaphod Beeblebrox, even plausible.

A: Do you know who that guy is?
B: Yeah, that’s Zaphod Beeblebrox.
A: Who’s Zaphod Beeblebrox?
B: I don’t know. I was just told that’s who that guy is.

The puzzle is that B seems to have contradicted herself. It seems that with her first word she said that she knows who that guy is. And with her second sentence, she said that she doesn’t know who Zaphod Beeblebrox is. But she knows that guy is Zaphod Beeblebrox, so presumably she knows who that guy is iff she knows who Zaphod Beeblebrox is. Contradiction. Yet her words sound consistent, even plausible. What has gone wrong?

Suggestion: The problem arises because we substitute into a non-extensional context. It is possible to know that guy is at the party without knowing Zaphod Beeblebrox is at the party, and hence possible to know who that guy is without knowing who Zaphod Beeblebrox is.
Reply: True, these substitutions are sometimes problematic. But this is a situation where we don’t just have co-referring expressions, but known to be co-referring expressions. And the knowledge of their co-reference is clearly salient to the speaker. So this probably isn’t what is going wrong.

Suggestion: The problem arises because ‘that guy’ is a quantificational rather than a referential expression.
Reply: That may well be true. If it is, drop all uses of ‘guy’ from the conversation so we have a simple demonstrative rather than a complex demonstrative. The conversation sounds a little more awkward then, but still coherent.

Suggestion: ‘Knows’ is context dependent, as Lewis, Cohen and DeRose have been arguing for donkey’s years.
Reply: Even if all the other objections to contextualism don’t work, it is hard to see how on any of their theories there was a change of context between A’s first utterance and B’s second utterance.

Suggestion: ‘Knows who’ is context dependent, even though ‘knows’ is not, as Boër and Lycan (among others) have suggested.

I think that’s basically right, and really I’m not sure how a non-contextualist can explain this data. The fact that B doesn’t even seem to have contradicted herself, or taken anything back, looks like a very strong argument for this kind of contextualism. (Compare the examples motivating ‘orthodox’ contextualism where there is a strong feeling that when a speaker first asserts, then rejects, that S knows that p after an alleged context shift. There there is a feeling the author is taking something back.) But in a recently posted paper David Braun has argued strongly against this kind of contextualism. The crucial argument, to my mind, concerns the following claim. David argues that if contextualism is true, claims like the following should be true, but they sound false.

‘Zaphod Beeblebrox is that guy’ is an answer to the question ‘Who is Zaphod Beeblebrox’, and B knows that Zaphod Beeblebrox is that guy, and so she knows an answer to the question of who Zaphod Beeblebrox is, but she does not know who Zaphod Beeblebrox is.

(This is a modified version of his (26) from page 23.) I’d like to have more to say here, but there’s not much more that I can say other that in this little story, this claim sounds true not false. If the claim was false (presumably because the last clause was false) then B’s last claim should sound like it is false. But it doesn’t, it sounds true. So I think the possibility of this conversation is a quite compelling argument for contextualism about ‘knows who’.

A Puzzle about Moral Uncertainty, and its solution

Here’s an interesting asymmetry between reasoning under moral uncertainty and reasoning under factual uncertainty. Or, at least, an interesting prima facie asymmetry, since there might be a simple explanation once we set everything out clearly.

The followinig situation is reasonably common in reasoning under uncertainty. We have three choices, A B and C. Which of these is best to do depends on whether p or q is true, and we’re certain that exactly one of them is true. If p is true, the best outcome will arise from doing A. If q is true, the best outcome will arise from doing C. Yet despite this, the thing to do is B.

Here’s an example. I’m in Vegas, thinking about betting on a (playoff) football game. The teams seem fairly even, and there is no points spread. As usual, to bet on a team I have to risk $55 to win $100. Fortunately, I have $55 in my pocket. Let A = I bet on the home team, C = I bet on the away team, and B = I keep my money in my pocket. Let p = the home team wins, and q = the away team wins. (Given it’s a playoff game, we can be practically certain that one of these is true.) So if p, I’ll be best off if A, and if q, I’ll be best off if C. Still, the thing to do is B, since both A and C have negative expected value.

Now the puzzle is that this kind of situation doesn’t seem to arise for moral uncertainty. Continue reading “A Puzzle about Moral Uncertainty, and its solution”


Ishani and I are about to head off to Canberra, so posting will be light until we arrive. One would imagine that being at a research school would be good for posting, but I’m not sure whether I’ll have 24/7 internet access, so we’ll have to see how that goes. If the computer batteries hold up there are lots of things I’d like to write up on the plane about the three very good conferences I attended, but we’ll have to see whether that is fully possible.