Saturday, May 27, 2006

The tao that can be told... not the eternal tao

The biggest problem for theoretical cosmologists in recent decades has been explaining why we are here at all. If the apparently random expansion rate of the universe were just slightly higher, the expansion would have been so rapid that protons and neutrons would not have had the chance to bond into atoms. It the rate were just slightly slower, the universe would have remained too hot for atomic nuclei to form. In either case, we would not exist.

So maybe there is something we don't yet know that constrains the universe to be one that's suitable for us. God, maybe. Or some yet unidentified law of nature.

String theorists have another answer. Our universe is just one of 10500 universes (1 followed by 500 zeros), with all conceivable values for the expansion rate, and we just happen to live in one that makes our existence possible. That's more universes than there are particles in this universe. Give me enough monkeys and enough typewriters and the odds are certain that one of them will clatter off the works of Shakespeare. By chance. Or so the story goes.

String theory or string theology? The multiple universes hypothesis is not quite science since there is presently no conceivable empirical test. But then there's no empirical test of the God hypothesis either. Neither hypothesis is worth getting worked up over. The phoebe has hatched her chicks. Her white throat shines in the musty dark of the root cellar. Life goes on.