After Stephen Hawking conceded that he'd lost his bet about the Higgs boson, I wondered why he had been on the wrong side of the bet. Why had he doubted the existence of a particle widely assumed to be an essential constituent of physical reality?

Hawking wasn't available to answer that question, but I did manage to have a long conversation with an American physicist who had also doubted the existence of the Higgs--Lawrence Krauss, author of The Physics of Star Trek and A Universe From Nothing . Krauss explained the generic reason that a number of physicists had doubted the Higgs: Its posited existence was suspiciously convenient. When you understand what he meant, I think you may conclude that physical reality is cooler than you'd thought. Here, as I understand it, is the deal:

Decades ago, physicists had found a way to unify--that is, fit into a common theoretical framework--two of the four basic physical forces: the electromagnetic force and the weak nuclear force. But there was one hitch: photons, the particles that mediate the electromagnetic force, have no mass, whereas the particles that mediate the weak force--the W and Z bosons--seem to have mass. And this theoretical unification wouldn't make complete sense unless the W and Z bosons were, like photons, massless.

So--here comes the suspiciously convenient part--physicists supposed that maybe the W and Z bosons didn't really have mass; rather, there was something--some feature of the universe--that made them behave as if they had mass. That "something" was dubbed the Higgs boson.

Click on "long conversation" link above to watch the video interview with Lawrence Krauss.