Where are the laws of physics come from ?

Where are the laws of physics come from ?

by : Aria Ratmandanu 

What are the laws of physics ?

         Philosophers of science have never achieved a consensus on what constitutes science. Still, most scientists have a good idea, even if they cannot lay it out in precise terms. Fundamentally, science deals with observations and their descriptions in terms of models. A model is more than simply a photograph-like image of a specific set of data. It should be able to successfully describe in a repeatable, testable fashion a whole class of observations of the same general type, enable the prediction of other unexpected observations, and provide a framework for further applications, such as in technology or medicine. 

           Well-developed and well-tested models of especially universal value are often called theories. However, as I indicated in the preface, I will try to avoid this term since it conjures up different and often conflicting meanings in people's minds. While some scientists and philosophers regard well-established scientific theories as the ultimate Platonic reality of the universe, some laypeople think of them as little more than idle speculations. At least the term model avoids both extremes and unnecessary philosophical disputation. 

        Physical models usually constitute a set of mathematical and logical procedures called algorithms. The driving force behind their development is not unquestioned authority, impeccable mathematical logic, or some inexorable drive toward progress. Rather, the models of physics and the other physical sciences evolve by a pragmatic process that exhibits many Darwinian elements. 

           First, physical models must work. They must agree with the data, pass stringent tests, and be capable of yielding useful results, as described above. Those that do not are rejected; they fail to survive. And, since scientific instrumentation becomes increasingly precise as technology advances, models must often undergo revision in order to keep pace. Second, models should be as simple as possible. They must be parsimonious in their hypotheses. When alternate models are available, those that make the fewest assumptions survive. But, they still must agree with the data. As Einstein said, "Things should be made as simple as possible, but not simpler.

            Third, models must be novel. They should tell us something we do not already know and do something new for us we cannot already do. Scientists pay little attention to many new models that are proposed by outsiders, not because they come from outside the club, but because they inevitably tell us nothing new, make claims that cannot be tested, or have already been proven wrong. For example, hundreds if not thousands of books and articles have been written claiming that "Einstein was wrong." Yet Einstein’s relativity, which is a century old at this writing, remains intact because no confirmed, repeatable experiment or observation has yet proven it wrong.

             The process of scientific development does not ensure that the models agreed upon are unique or the best anyone can come up with. And the process certainly does not mandate that any currently accepted model will forever remain immune from being rejected due to its failure to agree with some future observation. Often new models are proposed that improve on older ones by simplifying the assumptions or placing them on a firmer foundation. But empirical falsification is the primary measure by which previously successful models are discarded. Although falsification is neither necessary nor sufficient for distinguishing science from nonscience, as is sometimes claimed, it remains a crucial element of the scientific process. 

              None of this should be taken to mean that any one model is as good as another. Neither does it imply that models are simply speculations. As already indicated, a scientific model must agree with the data and pass stringent empirical tests before being accepted by the scientific community. Relativity and quantum mechanics are prime example of models that have been successfully tested many times with great precision. While single experiments have occasionally been reported that claimed to falsify either model, none have been confirmed by further investigations. In this chapter, I will briefly review the basic principles of physics contained in our models, as they are currently formulated. While I will more or less follow the historical sequence, I will not provide a detailed discussion of how these developments came about. I hope the reader will seek out that history from the many other sources that are available. My purpose at this point is to provide a concise description that can be referred back to in the following chapters. 

Where are the laws of physics come from ?

         We have seen that the origin and the operation of the universe do not require any violations of laws of physics. This probably will come as a surprise to the layperson who may have heard otherwise from the pulpit or the media. However, the scientifically savvy believer might concede this point for the sake of argument and then retort, "Okay, then where did the laws of physics come from ?" The common belief is that they had to come from somewhere outside the universe. But that is not a demonstrable fact. There is no reason why the laws of physics cannot have come from within the universe itself. 

         Physicists invent mathematical models to describe their observations of the world. These models contain certain general principles that have been traditionally called "laws" because of the common belief that these are rules that actually govern the universe the way civil laws govern nations. However, as I showed in my previous book, The Comprehensible Cosmos, the most fundamental laws of physics are not restrictions on the behavior of matter. Rather they are restrictions on the way physicists may describe that behavior.

            In order for any principle of nature we write down to be objective and universal, it must be formulated in such a way that it does not depend on the point of view of any particular observer. The principle must be true for all point of views, from every "frame of reference." And so, for example, no objective law can depend on a special moment in time or a position in space that may be singled out by some preferred observer. 

             Suppose I were to formulate a law that said that all objects move naturally toward me. That would not be very objective. But this was precisely what people once thought—that Earth was the center of the universe and the natural motion of bodies was toward Earth. The Copernican revolution showed this was wrong and was the first step in the gradual realization of scientists that their laws must not depend on frame of reference. In 1918 mathematician Emmy Noether proved that the most important physical laws of all—conservation of energy, linear momentum, and angular momentum—will automatically appear in any model that does not single out a special moment in time, position in space, and direction in space.

            Einstein's special theory of relativity follows if we do not single out any special direction in four-dimensional space-time. These properties of space-time are called symmetries. For example, the rotational symmetry of a sphere is a result of the sphere singling out no particular direction in space. The four space-time symmetries described above are just the natural symmetries of a universe with no matter, that is, a void. They are just what they should be if the universe appeared from an initial state in which there was no matter—from nothing. 

             Other laws of physics, such as conservation of electric charge and the various force laws, arise from the generalization of space-time symmetries to the abstract spaces physicists use in their mathematic models. This generalization is called gauge invariance, which is likened to a principle I more descriptively refer to as point of view invariance. 

           So where did the laws of physics come from? They came from nothing! Most are statements composed by humans that follow from the symmetries of the void out of which the universe spontaneously arose. They look exactly as they should look if they were not handed down from anywhere.

            Thus we are justified in applying the conservation laws to the beginning of the big bang at the Planck time. At that time, as we saw earlier in this chapter, the universe had no structure. That meant that it had no distinguishable place, direction, or time. In such a situation, the conservation laws apply. Now, this is certainly not a commonly understood view. Normally we think of laws of physics as part of the structure of the universe. But here I am arguing that the three great conservation laws are not part of any structure. Rather they follow from the very lack of structure at the earliest moment. No doubt this concept is difficult to grasp. My views on this particular issue are not recognized by a consensus of physicists, although I insist that the science I have used is well established and conventional. I am proposing no new physics or cosmology but merely providing an interpretation of established knowledge in those fields as it bears on the question of the origin of physical law, a question few physicists ever ponder. 

           I must emphasize another important point, which has been frequently misunderstood. I am not suggesting that the laws of physics can be anything we want them to be, that they are merely "cultural narratives," as has been suggested by authors associated with the movement called postmodernism. They are what they are because they agree with the data. Whether or not you will buy into my account of the origin of physical law, I hope you will allow that I have at minimum provided a plausible natural scenario for a gap in scientific knowledge, that gap being a clear consensus on the origin of physical law Once again, I do not have the burden of proving this scenario.