I had a discussion a few days ago with someone who told me that many very smart people he knew were also religious. I thought about that for a minute, and after reflection I just couldn’t agree. I don’t think one can be really smart and religious at the same time.

Yes, I know that some people who are academically smart and who have done great things, like Newton, were and are deeply religious. But in the old days you had no choice about being religious: you imbibed faith with your mother’s milk. And there was little chance to think for oneself, for it was either a death sentence or permanent ostracism if you questioned religion, and there were few ways to find like-minded souls.

Now, however, it’s different, for—except in some benighted lands—there is far more freedom to learn about nonbelief and hear the arguments against God; parents and society aren’t so insistent about…