I have been reading Robert Nozick’s Philosophical Explanations (a difficult text indeed) and have a question about his theory of knowledge; specifically, Nozick concedes to the knowledge skeptic that we cannot know, say, if we are a brain in a vat on Alpha Centauri (our experience of the world would be identical, says the skeptic, to what it is now, so we cannot know); but he then also notes that it does not follow that I cannot know, say, that I am typing on my computer. If I understand correctly, Nozick holds that my belief that I am typing tracks the fact that I am typing; I would not have the belief that I am typing if I were not typing. This, however, seems problematic to me; it seems to beg the question, i.e. assume the “fact” that I am typing is indeed a fact. Isn’t this what we precisely do not know according to the skeptic? What if I see a perceptual distortion, for example, a pencil wobbling like rubber when I place it between my thumb and index finger and quickly move it back and forth? My perception says it is “rubbery” but I know this to not be true; this seems to present a problem to what Nozick is suggesting, though I admit I may not understand the argument well enough.

Comments

Well spotted! Nozick holds that, in order for you to know p, it must be the case that, if p were false, you wouldn't believe p. This condition is not fulfilled when p is "it is not the case that I am a brain in a vat on Alpha Centauri being stimulated to have my present experiences": if p were false (if I were a brain in a vat on Alpha Centuri being stimulated to have my present experiences), then I would nonetheless be believing p.

But this condition may well be fulfilled when p is "I am typing." It is fulfilled if, were I not typing, I wouldn't believe that I am.

With this move, Nozick takes himself to have shown at least how knowledge is possible: it's possible that I am really typing and that, if I weren't typing, I wouldn't believe that I am. But do I know that I am typing or do I not? Well, according to Nozick, this depends on what I would believe if I weren't typing now. Nozick assumes that there's a definite answer to this question, a fact of the matter. But, even if we grant this, how can we find out what the answer is? How can we examine the possible world in which I am not typing that is closest (whatever this means) to the actual world in order to ascertain whether, in that possible world, I (or "I") believe that I am typing? We cannot find out. More generally, though we may well know many things, in Nozick's sense, and even know that we know them, in his sense, we cannot find out for any belief we might hold whether it constitutes knowledge or not (because, even if we can find out that our belief is true, we cannot find out whether the subjunctive condition Nozick deems necessary for knowledge is fulfilled or not).

So Nozick's showing how knowledge is possible shows the possibility of knowledge in something other than the ordinary sense. We may have knowledge in Nozick's sense, but we can in principle never find out whether we know anything and, if so, what. As you suggest, this isn't much of a victory over scepticism.

(BTW, I wrote up this critique in a termpaper in my first semester at Harvard and got a B+ from Nozick. So there you go.)

This doesn't seem at all clear. First of all, the argument assumes that, to know whether we know, on Nozick's account, we would have to know whether a certain counterfactual is true. But this isn't obvious. Water is H2O, but it doesn't follow that, to know whether something is water, you have to know whether it is H2O. Similarly, even if knowledge is (say) Nozick-style tracking, it does not follow that, to know whether you know, you have to know whether you track Nozick-style. That might follow if Nozick's account is construed as providing some kind of conceptual analysis, but even then there are issues that tend to go under the heading "The Paradox of Analysis".

Second, even if the foregoing is waived, I don't see why we can't know "whether the subjunctive condition Nozick deems necessary for knowledge is fulfilled". Surely we do have lots of knowledge about possibility, necessity, and counterfactuals. Of course, the epistemology of modal knowledge is a vexed issue, but so is the epistemology of everything else.

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