The Perimeter Institute in Ontario, Canada, is a research center dedicated to studying the underlying concepts of Physics. A prominent personality of the Foundation, Lee Smolin, one of the main ambassadors of loop quantum gravity, which is an alternative to string theory point of view on the unification of the fundamental forces in Nature, recently gave a speech on the nature of time, a central issue in the understanding of nature itself.
Smolin’s vision is different from the prevailing view that time is a human construct or an illusion in the image we have of the universe. Thus, he identifies himself as a naturalist or a person who believes that the Universe consists only of real objects that are governed by natural laws. However, he divides naturalists into two categories which are directly dependent on the nature of time.
The first category, which is represented by the majority of scientists, has its roots in the philosophy of the ancient Greeks and the atomists, such as Democritus and Lucretius, who argue that nature is nothing else but atoms moving in a vacuum. All the senses or experiences we have arise from the way they move and the position they have in space.
This view has evolved in modern physics, but the opinion that the properties of elementary particles are unchanged with time remains central. Indeed, in the typical model, elementary particles move in an unchanging background with invariant properties. Therefore, according to this view, all the other things apart from the particles and the vacuum are secondary or otherwise are derived from them.
Smolin proceeds to define a second category of naturalists, which differs only in a point, bringing the time in a central position. He states that the laws of the universe cannot be considered eternal, unchanged with time. That is because any explanation we give to what is happening is directly related to how something evolves in time.
Thus, laws that do not depend on time are meaningless, and that is why modern physics is facing a deep crisis. Therefore, the scientist concludes that time is real, and the laws of nature change over its course.
Basing on these ideas, Smolin supports the concept that the universe evolves by following a procedure similar to that of natural selection in biology, and that new universes can be born from black holes. Explaining how he came to this change of thought, the scientist says that he agrees with the idea that conclusions drawn from the laboratory experiments can be generalized to describe the behavior of the entire universe.