If the recent hoopla about the royal wedding wasn't enough to remind you, we live in a culture of celebrity, one where famous people command our attention and often pontificate on things they know nothing about. Obvious examples include the nonsense spewed out by Prince Charles about alternative medicine, and the former model Jenny McCarthy and her dangerous notion that vaccines are harmful because they cause autism. But these, of course, are easy targets. What are we to make of Ray Kurzweil (he of Singularity fame), who recently co-authored a book with a homeopath? Or of otherwise savvy political commentator Bill Maher, who doesn't trust vaccines or anything coming from "Western" medicine? And then there are highly respectable intellectuals, like Stephen Hawking, who write off entire fields of inquiry (philosophy, in his case), without apparently knowing much about them.

So what is going on here? Why do so many people listen to Jenny McCarthy? And why do so many bright minds go public with ridiculous notions? Is there a pattern? Can we do something to defend ourselves and the public from the celebrity attack on reason?