. >> i know this field moves very quickly, but in 2006 lee smollen, theoretical physicist in canada -- >> yes. >> -- wrote a book entitled "the problem with physics." >> the trouble with physics, yeah. >> excuse me. and it seems to be that he has, basically, abandoned string theory. so, chiefly because of lack of experimental confirmation. >> yeah. >> so my question is, has he abandoned it too early because of this? or can this carry on to future -- >> yes, it's a good question. and, you know, lee's a good friend of mine, and when e speak to him, he thinks his book is somewhat misinterpreted. what he claims he was really meaning to say in that book is string theory is not the only approach to putting together quantum mechanics and general relativity. there are other approaches. in fact, he's a champion and has been one of the founders of a competing approach called loop quantum gravity. and part of what he was saying was he feels too many people work on string theory, not enough people work on loop quantum gravity, and the health of the field would be more advanced if there was a more