"The notion of a connection between physical and mental potency is, of course, silly."

Jonathan Chait frets about what he sees as President Bush's obsession with physical exercise. Bush seems to exercise an awful lot and also seems to want his associates to do the same. Why?

My guess is that Bush associates exercise with discipline, and associates a lack of discipline with his younger, boozehound days. "The president," said Fleischer, "finds [exercise] very healthy in terms of … keeping in shape. But it's also good for the mind." The notion of a connection between physical and mental potency is, of course, silly. (Consider all the perfectly toned airheads in Hollywood — or, perhaps, the president himself.) But Bush's apparent belief in it explains why he would demand well-conditioned economic advisors and Supreme Court justices.

Is it really "silly" to believe that physical exercise has mental benefits? I've heard plenty of very smart people profess that belief. Personally, I'm not interested in exercise. I'm happy to walk a lot and have good stamina, but I don't set aside time in my day just for the purpose of exercising. And all that strenuous, self-improvement stuff people do -- ugh! I'd rather improve my mind with the traditional intellectual efforts: reading, writing, stimulating conversation, and plain old thinking. (All of which I can do while walking, by the way.) So I'm not personally following the exercise-for-the-mind plan. But is it silly to think exercise is good for the mind?

I do think it's silly to think that exercise is necessary for the mind. (It would be bad news for the very old and the disabled!) Right? But perhaps it is justified to form a negative assessment about the judgment and diligence of a person who is overweight and flabby, as Bush seems to do. What do you think? Is it unfair prejudice in hiring to make inferences about the mental capacities of a person who is in bad physical shape?