Even McCain is unsure. The “McCain Portrait” was right to remain agnostic on the precise number of McCain’s houses, and Yglesias is right to say this is partly a question of mereology. (I know a guy who knows more than pretty much everyone in the world about what Abelard thought about mereology. Hot. The jokes about Abelard and parts and wholes, they fly fast and furious.)

Two thoughts. First, in the “I can’t believe we might lose to this guy” category, seriously, think about what it would be like to wake up in the morning unsure of how many houses you own. I own one, for example. I know some people who live in one house and have some rental properties. Two, maybe three houses. Ok, that’s cool. It can be a good financial move. But they know.

Remember when people thought it mattered that a candidate didn’t know the price of a gallon of milk?

Second, it would be great if Obama’s new ad were slightly wrong about the number, so that he had to correct it publicly. “Oops, my bad– it’s really six not seven. So sorry. Let’s talk at length about how I made this mistake. About McCain’s many, many houses.”

I remember being at a talk where the speaker (I think it was Timothy Williamson) was discussing examples where the antecedent of a conditional provided evidence for the consequent, and he pointed out that in these cases there’s often a way in which the antecedent can be false that provides even more evidence for the consequent. E.g., “if a touchdown was scored, they’re playing football”– suppose the touchdown didn’t count because of a holding penalty. Ah, now there are refs and flags and this is definitely a game of football. Apparently GE Moore once gave his “here is one hand, here is another, thus there’s an external world” talk but improvised by replacing holding up his hands with pointing to a skylight while saying “that’s a skylight, thus…” only it wasn’t really a skylight but a trompe l’oeil thingie. Anyway. So too with “if McCain owns seven houses, he is one rich dude.” Oh, wait, it’s really eight? Or five? Please, let’s get into that conversation.