What ygert said. So-called superrationality has a grain of truth but there are obvious holes in it (at least as originally described by Hofstadter).

And think about it, how could a mathematician actually advocate cooperation in pure, zero knowledge vanilla PD? That just doesn't make any sense as a model of an intelligent human being's opinions.

Sadly, even intelligent human beings have been known to believe incorrect things for bad reasons.

More to the point, I'm not accusing Hofstadter of advocating cooperation in a zero knowledge PD. I'm accusing him of advocating cooperation in a one-shot PD where both players are known to be rational. In this scenario, too, both players defect.

Hofstadter can deny this only by playing games(!) with the word "rational". He first defines it to mean that a rational player gets the same answer as another rational player, so he can eliminate (C, D) & (D, C), and then and only then does he decide that it also means players don't choose a dominated strategy, which eliminates (D, D). But this is silly; the avoids-dominated-strategies definition renders the gets-the-same-answer-as-another-rational-player definition superfluous (in this specific case). Suppose it had never occurred to us to use the former definition of "rational", and we simply applied the latter definition. We'd immediately notice that neither player cooperates, because cooperation is strictly dominated according to the true PD payoff matrix, and we'd immediately eliminate all outcomes but (D, D). Hofstadter dodges this conclusion by using a gimmick to avoid consistently applying the requirement that rational players don't leave free utility on the table.