I had to link this interview with philosopher Tim Maudlin, in the Atlantic, when I read his observation that "The asking of fundamental physical questions is just not part of the training of a physicist anymore." But there's a lot more of interest in the interview as well. I found the article via Andrew Sullivan's blog; Sullivan found Tim's thoughts on the evolution of intelligence to be particularly interesting:

What people haven't seemed to notice is that on earth, of all the billions of species that have evolved, only one has developed intelligence to the level of producing technology. Which means that kind of intelligence is really not very useful. It's not actually, in the general case, of much evolutionary value. We tend to think, because we love to think of ourselves, human beings, as the top of the evolutionary ladder, that the intelligence we have, that makes us human beings, is the thing that all of evolution is striving toward. But what we know is that that's not true. Obviously it doesn't matter that much if you're a beetle, that you be really smart. If it were, evolution would have produced much more intelligent beetles. We have no empirical data to suggest that there's a high probability that evolution on another planet would lead to technological intelligence. There is just too much we don't know.

Indeed there is, but it points out some very interesting questions: is there a tendency, given enough time, for a species intelligent enough to produce technology to arise on an earth-like planet? Is there, perhaps, a tendency for it to inhibit the evolution of other such species? My personal guess (and it's just that, a guess, not supported by careful thought) is that there is such a tendency, but it takes a lot of time, it builds on, and is part of, a slow increase in the complexity of the most complex organisms. This is, of course, probably the "knee-jerk" view. Whether it inhibits the evolution of other species is something I'm less willing to speculate on (though if Neanderthals were another such species, we may have some evidence (one case!) for inhibition of the branching of a potentially technologically-capable intelligent species into two such species). Whether vertebrates have characteristics making it more likely for them to evolve technologically-capable intelligence than it is for, say, insects to evolve it is another interesting question.