Speaker: Alejandro Jenkins
Abstract. An experimental physicist is happy to measure, for example, the mass of the electron, and then to take that value as a given in her calculations. But a theoretical physicist would ideally like an explanation of why the electron has that particular mass, and not another. So far, all of our attempts to derive parameters like the measured mass of the electron from a fundamental, mathematically consistent theory, have been unsuccessful. In fact, some of our best current theories (like the theory of inflation in cosmology, and string theory in high energy physics) imply that there should be a vast number of universes besides our own, and that parameters like the mass of the electron could well be different in each universe. This has led some physicists to try to explain at least some of the parameters of our physical laws anthropically, which means that they are the only ones consistent with conscious, intelligent observers capable of measuring those parameters. I shall discuss instances in which this idea seems plausible and scientifically useful, and others in which it does not. The lesson seems to be that we still have a lot of work left before we can reasonably claim to understand --scientifically speaking-- why the world in which we live looks the way it does.
My talk will be based on an article co-authored with Dr. Gilad Perez, of the Weizmann Institute of Science in Rehovot, Israel, which apeared as the cover story in the January 2010 issue of Scientific American magazine.