Physics

One of the primary postulates of physics is that the laws of physics are universally true. I would like to illustrate this with an example.

Suppose there was a being that evolved in an environment which was far enough from any other matter that there was no gravity. This being, being intelligent, observed the world around him, and developed all the Newtonian laws of physics, except gravity. That is, gravity didn't exist in his environment, or the influence was so small that it could be ignored, so his laws would not even include this.

We may even postulate that his laws included an "uncertainty principle." That is, he observed that when he threw a ball, the ball traveled in a straight line, except there were slight perturbations which he couldn't account for. Of course we would say that it was due to the gravitational attraction of the objects in his universe, but he wouldn't understand that, so to him it was just some uncertainty, not enough to bother that he could attribute it to anything other than a certain uncertainty of the result.

Since his observation was that where ever he went the same laws applied - the same mass, the same straight lines, etc - he would conclude that the laws of physics were universally the same.

Then, through some magical means, our scientist suddenly finds himself on the surface of a planet. He is flabbergasted because here the laws of physics do not apply (according to him). That is, he throws his ball, expecting it to go in a straight line, but it doesn't. It curves. Being interested in physics, our scientist works out a new set of physical laws. It includes some mysterious (to him) bending, which he is able to account for by always assigning a direction to his universe. That is, he comes up with a concept of "up" and "down."

He also concludes that the laws of physics are not universal. That is, in some places his original laws hold, that is, Newton's laws, excepting anything dealing with gravity. In other places, this new set of laws hold true. But then, by combining the two sets of laws, he will salvage the universality of physics by saying that either one law is true, or the other where ever he is in space.

As his magical travels allow him to visit many different planets, he realizes that there needs to be another constant added to his new set of laws, which I'll name the "gravitational constant." (Note, I simply use this for a name. Our scientist, as yet, has no concept of gravity, only this mysterious bending.)

Years go by, and a new scientist notices a connection between the size of the gravitational constant, and the size of the planet. Therefore, he develops a new "Universal" physics in which both of these previous sets of laws are true, but in different cases. That is, he develops that whole of Newtonian physics, with gravity added, and proposes that these are the universal laws.

The point here being that the laws of physics are universal by definition. If there is a portion of the Universe in which the laws don't apply, then physicist would (rightfully) create a new "force," or whatever, which would make the laws true.

For example, if one uses only the laws of physics that are obvious at the macro level, then it becomes a big mystery why the nucleus of an atom holds together. That is, there are many positively charge protons in the nucleus, so, by rights, the laws of physics that we understand on the macro level would say any nucleus, except light hydrogen, should fall apart. Therefore, physicist came up with a new force, which only applied over a very short distance, but which is very strong over that distance, called the "strong force." So now we "know" that the nucleus is held together by this strong force, which doesn't apply on the macro scale, and the universality of physics is once more preserved.

Then, one day, an observer in our universe is looking at the stars one night, and notices that the light from distant stars doesn't get shuffled due to differences in the speed of the light particles, as the "new" universal physics would suggest. This is true, even for eclipsing binary stars. The result is he concludes that the speed of light is constant, regardless of the source.

Therefore, he develops all of Maxwell's theory. So now there are two physics, one which is the new universal physics, and the other is Maxwell's theory. In order to get a grasp on this situation, the scientist decides to say that light is a wave in some mysterious substance which fills all of space called "ether," whereas the things which require the universal physics are actual objects.

Then in our mythical universe, one day some enterprising physicist decides to invent a machine which will use the two laws of physics together to always tell you how fast you are going through the ether. ...

For people reading this who may not be up on physics, Maxwell's theory, the wave idea, and the speed machine were really done. The first by Maxwell, who also thought of light as a wave, and the later by two scientist named Michelson and Morley. If Newton's laws were true, and Maxwell's laws, then their machine would have worked, but it didn't, probably the biggest, most public failure in all of the recent history of physics. This failure lead to Lorentz proposing a "contraction" which was quantified by his transformations. Roughly, this was equivalent to the wave theory of light by Maxwell, it was an attempt to salvage the old physics. Then an upstart named Einstein came along, and proposed a "new" new universal physics, which he called "Relativity," and the universality of physics was once more confirmed.

Therefore, I can say, with some certainty, that the laws of physics apply universally, and this can be illustrated by the fact that they don't, as above.