I’ve been thinking a bit about dogmatism recently, largely because I think I should extend the rather compressed discussion of ‘externalism’ at the end of “Scepticism Rationalism and Externalism”:http://brian.weatherson.org/sre.pdf. So I’m writing, one stage at a time, a longish paper arguing that various recent attacks on dogmatism don’t do enough to show that it is false. The paper is a long way from written, but I thought I’d post the introductory sections in order to get some feedback.
bq. “In Defence of a Dogmatist”:http://brian.weatherson.org/dog1_3.pdf (sections 1-3)
The main points of these sections are to (a) argue that dogmatism is a distinctive kind of response of scepticism and (b) point out that the whole paper is a statement against interest because I’m not actually a dogmatist. Obviously (a) is a little more interesting to most people than (b). The argument for that goes by setting out what I take to be the complete form of the argument from sceptical hypotheses. This is sometimes put forward as a two premise argument, one closure premise and one premise about the unknowability of the falsity of BIV type hypotheses. I think it is a more compelling argument if the sceptic argues for the second premise rather than asserting it as an allegedly intuitive premise. In the paper I go over this a bit more slowly, but I think one very compelling form of argument is the following.
# If I know I have hands, then Im in a position to know that Im not a handless brain in a perfectly functioning vat (BIPV)
# If it could have turned out that Im a handless BIPV, then Im not in a position to know a priori that Im not a handless BIPV
# It could have turned out that Im a handless BIPV
# If it could have turned out that Im a handless BIPV, then it could have turned out that Im a handless BIPV with the same empirical evidence as my actual empirical evidence
# If Im in a position to know a posteriori that Im not a handless BIPV, then it could not have turned out that Im a handless BIPV with the same empirical evidence as my actual empirical evidence
# So I dont know that I have hands
Prima facie, every one of those premises is hard to deny I think. Dogmatism gives us a way to deny 5, and I think the strongest argument for dogmatism is that it lets us accept the other premises, or at least their counterparts in other sceptical arguments. As I say in section 2 of the paper, I think dogmatism is more plausible as a response to the inductive sceptic than the external world sceptic. But I’ll keep talking about external world scepticism in this blog post. (Roger White discusses the dogmatist response to inductive scepticism “here”:http://philosophy.fas.nyu.edu/docs/IO/1180/induction.pdf.) Here are a few other thoughts about the argument.
* Premise 5 is a little confusing, but the contraposed form of it, which schematically says that if your evidence is consistent with _p_, then you don’t know that not _p_ a posteriori, seems very plausible.
* The argument isn’t obviously valid, but if we take it to be definitional that a posteriori knowledge is just knowledge that isn’t a priori, then it is classically valid. (It is also, I think, intuitionistically valid, though this is a little harder to show.)
* One nice consequence of setting out the argument this way is that we see exactly how semantic externalism is a response to the argument (it rejects premise 3) and how Williamson’s evidence externalism responds to the argument (it rejects premise 4).
* The argument undermines the appeal of contextualism _as a response to scepticism_. I don’t think this ‘appeal’ has been part of the core argument for contextualism for nearly a decade now, but this gives us a clear reason for saying why. Let us consider the relation that ‘knows’ picks out in an ordinary context. It’s still hard to say which of premises 1 through 5 are false, because 3 and 4 don’t involve ‘knows’, and 1, 2 and 5 follow from general principles that are plausible independent of BIV considerations, and it is hard to see how context change could cause us to change our mind about those principles.
So while I’m sure it could do with some fine-tuning, I think this is a pretty interesting form of the sceptical argument, and it makes the philosophical interest of dogmatism fairly clear.