In my post on leaving philosophy, I said that “I think philosophy gets even fewer real results than the meager results that philosophers have sometimes claimed,” linking to the Amazon page for What Philosophers Know, by Notre Dame professor Gary Gutting.

As an explanation for my comment, I’m going to do a three-part blog review of Gutting’s book. The first part of my review will correspond to part I of the book, which is subtitled “The limits of philosophical argument.” Gutting conveys the main point of the section when he says:

How often have we heard (or told others) that Quine refuted the analytic-synthetic distinction, that Kripke proved that there are necessary a priori truths, and that Gettier showed that knowledge cannot be defined as justified true belief? But, although I entirely agree that Quine, Kripke, and Gettier have achieved something of philosophical importance, a careful reading of their exemplary texts does not reveal any decisive arguments for the conclusions they are said to have established.

I think Gutting’s selection of the three claims (about Quine, Kripke, and Gettier) represent a nice variety, in terms of how plausible the claims are. I don’t think I’ve ever met anyone who thought Quine refuted the analytic-synthetic distinction, and based on the PhilPapers survey, the analytic-synthetic distinction seems to be alive and well. With Kripke, on the other hand, I do get the impression that a lot of philosophers think Kripke’s arguments are decisive, though I’ve personally never found them convincing. With Gettier, though, his critique of the JTB analysis of knowledge seems to me about as good a candidate for a conclusive philosophical argument as there could be. (Non-philosophers: don’t take my word for it. The Gettier paper is short and easy to read, so go read it!)

For this reason, I find the discussion of Gettier especially interesting, and I actually think Gutting makes a good point:

If I say that all women are under six feet tall, then the fact that a women is six-foot-four refutes my claim. But the force of the argument depends on the obviousness of the counterexample. In just what sense are the Gettier cases obvious? I suggest we can fruitfully judge the obviousness of a claim by the epistemic price of refusing to accept it. If I’m presented with a woman who certainly looks well over six feet and whose height has just been measured (by competent judges) as over six feet, denying her height requires me to deny the evidence of my own senses and the validity of a measurement I have every reason to think is reliable. To maintain my claim that there are no women over six feet will involve me in a cascade of epistemic absurdities that makes holding on to my claim a common-sense impossibility.

Gettier counterexamples do not have this sort of obviousness.

Gutting reinforces his point by giving examples of philosophers who’ve defended the justified true belief analysis of knowledge in spite of Gettier, and by noting an x-phi study showing that “non-philosophers are far from unanimous regarding Gettier intuitions.”

I think all of that is right, and I’d add that not only is Gettier’s argument not as decisive as our evidence that there are women over six feet tall, it’s hardly as decisive as the evidence for the major findings of 20th-century science. I say this in spite of the fact that it still seems to me that the Gettier cases are cases of justified true belief without knowledge. The distinction here is between what seems true and what’s genuinely obvious. I know in my past thinking about philosophy, I haven’t always paid enough attention to that distinction, and I suspect many philosophers are guilty of the same failing.

I find Gutting less convincing, though, when he claims that philosophical reflection on the work of Quine, Kripke, and Gettier has generated some knowledge other than what those philosophers claimed. Gutting claims, for example, that Quine has showed us that the analytic-synthetic distinction cannot be defined in non-modal terms, and that in most cases “justified true belief” is the correct definition of knowledge.

An obvious worry, which (unless I’ve missed something) Gutting doesn’t address is this: if Gettier’s arguments aren’t decisive, what are the chances that there will be better reasons for accepting claims like these? If we use the standard “to deny it involves as much absurdity as denying that there are women over six feet tall,” what are the chances that Gutting has reasons his claims that meets that standard?

Indeed, I can think of specific reasons to be skeptical. Maybe no one has given a good definition of the analytic-synthetic distinction in non-modal terms, but I think that’s at best weak evidence that no such definition could be given. And it seems confused to talk about a definition working in most cases: if you go around trying to determine whether things are human by checking whether they’re featherless bipeds, you’ll get the right answer most of the time, but it would be a mistake to say “the featherless biped definition of humanity works in most cases.”

Now, I don’t claim these criticisms are decisive rebuttals to what Gutting says about the analytic-synthetic distinction, or what he says about knowledge. I do think it’s clear, though, that Gutting’s reasons for his claims aren’t any more decisive than Gettier’s reasons for denying that justified true belief is knowledge. And I don’t think Gutting has shown that there are very many philosophical claims that are well-established in any sense, or that there are any philosophical claims with truly decisive arguments in their favor.