One very good reason Bill Nye should not have agreed to debat Ken Ham

This is exactly what we feared. CNN is promoting the debate and treating it as a legitimate discussion between two equally credible points of view. That's what Ham wants out of this -- to be granted equal status with science by the corporate media. And he got it. That's why we don't have public debates any more with holocaust deniers, HIV denialists, tobacco denialists, or global warming denialists.

There is nothing to debate. They are all either deluded or liars. The facts are not in question. But the purveyors of anti-scientific nonsense have a big advantage in these public debates precisely because they feel no responsibility to be honest, logically coherent, or parsimonious in their conclusions. Scientists feel compelled to assert their open-mindedness and say things like, "rabbit fossils in the Cambrian would change my mind," but to the average viewer, that just makes it seem like they are unsure of their beliefs. Which makes them less credible.

The science denier can just spew out a whole bunch of preposterous assertions, which the defender of science then tries to systematically rebut but he can't get through 1/10th of them, and meanwhile he doesn't get around to what he wants to say. Viewers don't have access to the large body of evidence or the technical means by which scientists evaluate it so argument by assertion works just fine. All you see is two people making contradictory claims, one of whom is ponderous and hard to understand, never manages to present a complete and coherent argument, and seems to lack the courage of his convictions; the other speaks in simple sentences, manages to marshal 5 times as many [apparent] facts, and to present a coherent whole argument. 

It's a fool's errand, Mr. Nye. I wish you wouldn't do it.