WHAT IS THE FUTURE OF COSMOLOGY? - cont.
Thus, rather than leading to the discovery of a single fundamental theory, string theory seems itself to point to the need to include an historical aspect in fundamental physics. If we want to know all the answers to our questions about electrons and protons, we are going to have to understand why the universe we see around us emerged from the Big Bang with one set of laws rather than another.
“We in the audience are all agreed that your theory is crazy. But what divides us is whether it is crazy enough.”
—NIELS BOHR, after listening to Wolfgang Pauli present a theory of everything.
I have proposed one possible answer: something like natural selection acts on the choice of the laws of physics. The basic idea is that black holes give rise to new regions of space and time, and that at these events, which resemble our Big Bang, the laws of physics can change. When worked out in detail, this idea leads to a scientific theory which makes predictions which are testable. The basic prediction is that no small change in the masses of the elementary particles or the strengths of the forces would lead to a world with more black holes than ours. So far, although a number of astronomers have tried to find counterexamples, this prediction has held up. I can also deduce from the theory that certain things will never be seen. For example, a neutron star with a mass at least three times that of our sun is incompatible with the theory. If one is seen, the theory is disproved!
It is also possible to imagine other ways in which historical elements could come into the laws of nature. Indeed, we are discovering that there it may be that space is itself the result of spontaneous processes of self-organization. Processes of self-organization other than natural selection have been studied by people like Per Bak and Stuart Kauffman for some time, and they are known to occur in a variety of situations. It may very well be that mechanisms like self-organized criticality, which Bak and Kauffman describe, may play a role in the emergence of space itself, from a complex primordial network of interactions.
This idea is being studied now by a number of people. Although it is too early to say if it will work, I can say something about how it comes about. The reason is that those of us studying the problem of combining general relativity with quantum theory have understood that the geometry of space must be discrete. Just like matter is made of atoms, space itself must be made of discrete bits.