Dialetheism is easy to mock. Indeed, the first I’d heard of it, and the only time I’d heard of it before skholiast’s post, was in two of Ryan Lake’s Chaospet comics that made fun of it. Lake’s comics note apparent problems with dialetheism: if nothing is bad about contradictions, as Priest suggests, then doesn’t that basically allow one to say anything at all? Doesn’t one then just immediately solve every hard problem without having to think about it, by saying (as Lake’s character Nester does) that “the mind both is and is not the brain”?

Priest’s article tries at length to refute the view he calls “explosion.” Explosion is a view usually taken for granted in contemporary formal logic, although (so he claims) not held by Aristotle, that any statement at all follows logically from a contradiction. (While the article itself is behind a pay wall, Priest makes many of the same points in a Stanford Encyclopedia article on the topic.) We are not bound to accept all contradictions, he argues, if we merely accept some; and most of the unfortunate logical consequences we associate with contradiction derive from accepting all contradiction.

I haven’t had the time yet to dive into the details of Priest’s argument and examine whether he’s adequately convincing. Instead, let me assume for present purposes that in the details of his argument he is basically right. What then would his being right imply? Far less, I suspect, than he claims: certainly not that nothing about contradictions is bad.

For as it turns out, Priest himself accepts that there’s usually something wrong with contradictions. In the fourth section of his article he tells us that contradictions are “a priori improbable”; most contradictions in fact turn out to be false. So “inconsistency is a rational black mark,” and “[i]f we have views that are inconsistent we are probably incorrect.” (424) In giving examples of potentially true contradictions, Priest looks primarily at paradoxes, especially the liar paradox (statements such as “This statement is false”) but also the kind of paradoxes associated with Zeno of Elea. Priest claims that the easiest way to understand the liar paradox is to say that the statement “This statement is false” is both true and false. The only reason to reject such a claim is that it is a contradiction; a dialetheist can resolve the paradox by affirming that contradiction. But Priest is quite ready to say that “we do not deal with these kinds of situations very often.”

This isn’t to say that Priest’s dialetheism is insignificant. It’s led me to reinterpret key Madhyamaka Buddhist figures, from Nāgārjuna up to Śāntideva himself. I’ve noted, in my dissertation and elsewhere, that these thinkers see a normative force in non-contradiction: to identify a claim as a contradiction, other things being equal, is to say that something’s wrong with it. But other things are not always equal, and I think it’s fair to say that Nāgārjuna and Śāntideva do not accept a law of non-contradiction in anything like the sense Aristotle intended. I’m not convinced by their views of logic, but I think Priest has pointed me to something important in the way they work. And if it were to be the case that the Madhyamakas are indeed correct, then Priest’s view might turn out to be more significant than he himself is ready to claim.

http://xkcd.com/675/
http://chaospet.com/2009/12/14/164-it-goes-both-ways/

The two comics together nail it all pretty well, I think. Make sure to hold your mouse cursor over each comic strip for a few seconds to get the author’s comments, too.

While I’m linking to philosophical webcomics, I should also mention Ryan North’s highly enjoyable Dinosaur Comics. Longer post coming later today.