Michael Segal interviews Lee Smolin in Nautilus:
Your Cosmological Natural Selection hypothesis suggests that the laws of nature change in time. How can that be possible?
There are two kinds of explanations as to why some system is one way rather than another way. One is that it has to be that way because there’s some fundamental principle that makes it so. In fact, my generation was raised to find the unique set of laws which would satisfy the principles of relativity and quantum mechanics. We thought we would find a unique answer. But now we know that there are many, many different possible laws compatible with the principles of nature. The only other way in science that things get explained in a way that leads to testable hypotheses is if there’s some dynamical process acting in time, which makes the world come out the way it did.
What does that mean for our understanding of time?
The standard view in physics is that time isn’t fundamental, and that it emerges as an illusion out of the action of the laws. But if the laws evolve, that can’t be the case; time has to be more fundamental. If laws can change in time, then I take that almost as a definition of time being real. The arguments that Einstein and other people give for time being an illusion assume that the laws of nature never change. If they do change, the case that time is an illusion falls apart. It means that time is more fundamental than the laws of nature.