At the end of my book Nature and Nature’s God I point out that the history of science provides inductive confirmation of the philosophical truth that motion cannot continue in any meaningful sense on its own without beginning and end. I point to the repeated process in which new developments in sense were taken by some to provide support for beginningless and endless motion, only for further developments in science to clarify that this was impossible. There are many pairs of developments in which this is exemplified. In the book I discuss inertia and the subsequent analysis of collisions as less than perfectly elastic; the conservation of energy and the discovery of the second law of thermodynamics; statistical mechanics and the radiation of energy as photons that then undergo cosmological redshift. Big bang cosmology is another episode, but I did not note in the book another aspect of its development that repeats this pattern.
Einstein was initially excited that general relativity would show that the universe exists in a steady state, without beginning or end. But in his debates with De Sitter it soon became clear that general relativity won’t allow for a beginningless and endless universe. At best the universe can be in an extremely unstable equilibrium; even quantum fluctuations will push it out of equilibrium, and a gravitational runaway effect will cause the universe to eventually collapse or expand without end, diluting its contents into effectively nothing. The fact that GR requires a universe with a beginning is helpful to note. I skipped over this and went right to inflationary cosmology and the BVG theorem.
It is very illuminating to study the history of science and to note this pattern. Those who hope to get a beginningless universe (without divine sustaining action) out of the developments of science have been continually disappointed. They are chasing after a pie in the sky: a perpetual motion machine.