The philosopher Leo Strauss once spoke of the reductio ad Hitlerum. By this he meant the promiscuous tendency of people to try to score a debating point by comparing their opponents to Hitler. The form of the argument is something like this: "My opponent doesn't like strawberry ice cream. Hitler didn't like strawberry ice cream. My opponent is just like Hitler." Strauss's point was that the reductio ad Hitlerum is the mark of the lazy and illogical mind.

Sure enough, here is Richard Dawkins employing the reductio against me in a recent comment on his website richarddawkins.net. Referring to me and a conservative rabbi named Boteach, Dawkins writes: "It occurs to me that people like Boteach and D'Souza may be honestly unaware that they shriek and yell in such an unbecoming way. Maybe this is just what preachers of a certain kind do. So people who profession is to preach, or who live their lives surrounded by preachers, just don't hear their ugly yells and shrieks as we do. They have become so inured to the preaching style of yelling that the resemblance to Hitler passes them by.

"I'm not suggesting that Boteach and D'Souza have literally damaged their ears. But at a higher cortical level they may have become desensitized through years of preaching, and exposure to preachers, so they don't hear, and literally and honestly don't understand, the strong resemblance to the hideous vocal style of Hitler. Once again, I need to emphasize that the comparison with Hitler is limited to vocal style. Of course nobody is suggesting that either Boteach or D'Souza have similar opinions to Hitler, or resemble him in any other way at all.

"But imagine listening to a Boteach speech or a D'Souza speech or a Hitler speech with no knowledge of English or German. I suspect that you'd hardly notice the difference. Contrast it with a speech by Christopher Hitchens. The voice is strong, even a little thrilling. But there's no hysteria there. The words match the content: measured, thoughtful, strong and powerful but never hysterical."

Had this not appeared on Dawkins' website, I would have thought it parody. But who can bring himself to laugh? Does Dawkins have any idea of how gross it is to compare a rabbi to Hitler on the sole ground that both men had a tendency to raise their voices? If this isn't anti-Semitism at the very least it shows a shocking disregard for what the Holocaust means to Jews. Perhaps the kindest explanation is that Dawkins has a pathological hatred for the clergy, and Boteach is a rabbi.

I, on the other hand, am a scholar and author. Dawkins, who knows this, weirdly insinuates that I am a preacher or spend most of my time with preachers. This couldn't be further from the truth. I have been a secular writer for 20 years and mostly I speak to university audiences and business groups. Moreover, the atheists I debate, like Michael Shermer and Peter Singer and Christopher Hitchens, routinely tell me how effectively I use wit and repartee and rhetorical understatement and learned analogies to make my points. Far from using "yells" and "shrieks," the only time I can recall even raising my voice was during my debate with Daniel Dennett, and this was not because I was upset but only because the microphone was not working properly.

I suspect that Dawkins has come up with this pathetic reductio ad Hitlerum in order to justify his cowardice in not debating me. "I can't debate Dinesh because he will use his Hitler voice to shout me down." Isn't the real problem that Dawkins has used his zoologist's credentials in order to wander into fields (physics, astronomy, history, phiosophy, anthropology, theology) where his knowledge is embarrassingly limited? I suspect he's worried that in a debate I will exposure his ignorance and make him an international object of ridicule.

Why not prove me wrong, Richard? Come out from under your desk and take me up on my invitation to debate. I promise to speak in whispers!

And here's some news from our Department of Atheists Who Aren't Wimps: On Friday July 11, I will debate Christopher Hitchens at the big libertarian conference Freedom Fest in Las Vegas. Our topic is "Christianity, Islam and the War on Terror." For more information go to freedomfest.com or simply click here.