But what's a "mental difference?" To take an extreme hypothetical, if both men and women spoke 16,000 words per day at 30 words per minute, but the men spoke only of methods for playing football and the women spoke only about feelings regarding food, surely that would be some kind of "mental difference," wouldn't it?

It's like saying there's no difference between cars and bicycles, because some people get where they're going by car and other people get where they're going by bicycle, but both get where they're going. And in a very limited sense that's true.

--s