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I have not focused so far on the concept of Natural Laws or Laws of Nature in the discussion above (although, I do come back to certain issues related to the so-called Laws latter). It seems to me to be of more interest to explore the concept of causality without that traditional baggage. A related and perhaps more typical form in which to present the philosophical questions at issue here is to ask: Are there invariable Laws of Nature and, if so, what are they? This approach, however, presents a variety of controversies that do not seem to me to be necessary for the undertaking here and seem to present a potentially significant diversion, with attendant distractions.

The Laws of Nature, if they exist, have been assumed by many scientists and philosophers of science to be constant and unchanging both in space (throughout the Universe) and in time (over billions of years). In addition, the Laws of Nature are assumed to incorporate or be based upon certain “constants” of nature that also do not change in space or in time (like the speed of light, the gravitational constant, etc.). See Barrow, The Constants of Nature (2003). The assertion is made that “[i]n fact, it is not logically possible for all the Laws of Nature to be changing. Either there are no laws at all or there are invariant laws.” Barrow, Theories of Everything, p.27.³⁶ This statement, however, turns on the definition of Law, so it is essentially circular and almost vacuous.

Indeed, not all scientists have accepted the assumption that the Laws of Nature are constant and eternal. Theoretical physicist Lee Smolin unambiguously asserts (with no evidence) that physical laws have evolved and will continue to evolve through time. Time Reborn: From the Crisis of Physics to the Future of the Universe (2013), p.xxv. He claims a long tradition for this view, providing quotations from Paul Dirac, John Archibald Wheeler and Richard Feynman that at least acknowledge the possibility that the Laws of Nature change and, perhaps, evolve.³⁷ Similar points can be made about the supposed “constants” of nature, the numerical values of the constant factors contained in many natural laws which we shall discuss below—things like G (the gravitational constant), c (the speed of light) and h (the Planck constant). The laws of nature often set forth an algebraic relationship between two entities that includes a constant factor that is assumed to be the same for all examples, regardless of when or where they might be found.

There are other types of constants as well, numerical ones. “The laws of science, as we know them at present, contain many fundamental numbers, like the size of the electric charge of the electron and the ratio of the masses of the proton and the electron. We cannot, at the moment at least, predict the values of these numbers from theory—we have to find them by observation… .” Stephen Hawking, A Brief History of Time, p.125. In other words, the theories do not generate the numerical values of the constants; the values exist as a factual matter.

Over very short periods of time (years, decades or, in some cases, a couple of centuries) efforts have been made to measure these constants. As we shall discuss, the achievement of supposed definitive values has not always been easy. But, even where the empirical results are very robust, they are necessarily limited to the values of those constants in modern times. It is simply assumed that they have always been and always will be the same.

Moreover, it is certainly not obvious that the laws and constants that we have observed on Earth are equally applicable throughout the Universe. Many of these laws and constants have been extensively tested and measured empirically on Earth and within our Solar System. The theories of which they are part are normally presumed to apply everywhere. And, generally, there is nothing in the theories that would suggest otherwise. However, as we shall see, we currently know that many laws of our observable macro-world (like Newton’s laws of motion) as well as many of our maxims of common sense do not apply at very small scales, the so-called quantum world. The world of the atom is some ten orders of magnitude smaller than our observable world. The Universe is estimated to be some 14 orders of magnitude larger than our Solar System. See, e.g., Alexander Unzicker and Sheilla Jones, Bankrupting Physics: How Today’s Top Scientists Are Gambling Away Their Credibility (2013), pp.57, 60–68.³⁸ How can we be sure that the same Laws apply to the very large scale phenomena, when they do not apply to the very small scale?

Indeed, one of the great discoveries of Einstein was that Newton’s Laws of Motion would not accurately describe the behavior of bodies everywhere in the Universe. Einstein’s theory of General Relativity has wider application than Newton’s Laws, covering a broader set of circumstances, most of which are quite remote from our own experiences. “[F]ar out in space lie environments differing hugely from our own. We should not be surprised that commonsense notions break down over vast cosmic distances, or at high speeds [approaching the speed of light], or when gravity is strong.” Rees, Just Six Numbers, p.37.

Even if one does not use the word Law, there are interesting questions as to whether our perception of regularities and rules may simply be an illusion (that possibility does not seem very likely, since the existence of regularities within the portions of the Universe we can observe seem beyond dispute) or whether our speculation that there are laws reflects a misinterpretation of the evidence (for example, these regularities could be a mere coincidence of our rather small part of the Universe). See, e.g., Barrow, Theories of Everything, pp.24–26.

These issues obviously become important when one gets to astrophysics and cosmology. However, it is not clear to me that our understanding of the world we can perceive with our senses is enhanced by the issues that arise in connection with theories about the Universe. For example, suppose that we were able fully to set out the rules that govern physical phenomena in our temporal and spatial location (say for the 2 billion years on either side of now and in the space that is within 5 billion light years of Earth). Such “rules” might not be “Laws,” because they might not apply to the very beginning and end of the Universe or across the vastness of space, but they would undoubtedly be highly useful to us in our world and would seem to constitute a pretty successful scientific achievement. The same comments apply to the assumed “constants of nature.”

To the cosmologist, it matters greatly whether these constants always were and always will be the same. For most of us, however, the conditions at the ends of the Universe—both temporal and spatial—may not be of very much concern.