"This, I suspect, is one of those truths so horrible that you can't talk about it in public."

Charles Murray talked about in "The Bell Curve."

And Ayn Rand wrote about it repeatedly.

There's "smart" and then there's "smart enough for your cognitive mechanisms to reliably decide to sign up for cryonics".

And then there's "smart enough not to use a terribly controversial and questionable position, which has repeatedly been the basis for criticism of my judgment, as an example of an extremely intelligent decision".