As I suggested yesterday, human intuition gives us a lousy set of tools with which to understand the underlying nature of physical reality. The English language supplies a few pitfalls too. Last night I started reading Black Holes & Time Warps by Kip S. Thorne. Thorne is described on the back cover as the Feynman Professor of Theoretical Physics, Emeritus, at the California Institute of Technology, so we can fairly conclude that he knows whereof he speaks. And yet, toward the end of Chapter 1, we find this odd passage (italics in the original):
“…most physicists are driven to believe that these sequences [of laws] are converging toward a set of ultimate laws that truly governs the Universe, laws that force the Universe to behave the way it does, that force … the Sun to burn nuclear fuel, force black holes to produce gravitational waves when they collide, and so on.”
I may be only a poor dumb shitkicker from Illinois, but I know that’s just plain wrong. The way that’s phrased, it seems to say (quite clearly) that the laws of physics that physicists strive to understand are an outside force, a force that compels, for example, an electron or a photon to behave the way it does. But that’s not the case at all. There is no outside force that compels a thing we call an electron to behave like an electron rather than like a quark, a muon, or a neutrino.
An electron is not even a thing in that sense, and the laws of physics are not laws in that sense. They don’t compel any fundamental particle to behave the way it does. Rather, the laws of physics are simply descriptions of what happens. There is no thing called an electron that behaves in any manner at all. What we call an electron is, on the contrary, a tiny portion of a vast interaction (ultimately, of the whole Universe) that we have isolated for purposes of analysis and description. But it isn’t a separate thing. An electron never exists in isolation, because there isn’t any isolation in which it could exist. We can only describe it in terms of what it does with respect to the nucleus of an atom, or in terms of what it does when it releases or absorbs a photon, or whatever. Absent these interactions, the term “electron” would be meaningless.
This may sound rather mystical, and in a sense it is. The Universe is all a single thing. We can describe how it behaves. It vibrates. It resonates. It pushes and pulls at itself in unbelievably complex ways. But there is no force compelling it to behave in that manner. It just does. Even that sentence (“It just does”) is wrong, because there isn’t any “it” that “does” anything. The Universe is those vibrations and resonances. That’s all it is. It’s like the ringing of a bell — but there’s no bell.
Okay, I didn’t intend that to be a pun, but I’m not going to back away from it.
Gradually, over the course of eons or over a stretch of billions of light-years, the vibrations and resonances may change. The Universe may come to behave in some other manner — because there are no “laws” that would prevent it.
Will physicists ever be able to derive a tidy set of equations that perfectly describe every interaction that can conceivably occur in the Universe, past, present, and future? I doubt it. Not just because of the limitations of our instruments or the limitations of our mental abilities but because the Universe is continuous rather than discrete. (There is a notion floating around that at the deepest level space-time is digital — composed of discrete cells. I’ll point out the deep flaws in that idea some other time.)
Every time physicists think they have a law of nature nailed down, a few years later they have to add a fudge factor, because the real Universe doesn’t know anything about these supposed laws. The fudge factors have come to resemble the epicycles of Ptolemaic astronomy, and that analogy may suggest that physicists don’t yet know as much as they think they do.
Thorne’s book begins with an as-if science fiction tale in which a spaceship crewed by humans investigates a few black holes. The weirdness that they encounter is fascinating, but Thorne barely mentions the caveat: No human has ever observed a black hole. We don’t actually know how matter, energy, and spacetime behave in such a bizarre region. All we have are the equations. We know that the equations are very good at predicting a bunch of stuff, such as how the light from a distant star is bent by the sun’s gravitational field. But everything to do with black holes and the Big Bang is pure extrapolation. In such extreme circumstances, what other fudge factors, at present unknown, might become huge? We don’t know.
Sure, if there were physical laws that compelled the entire Universe, everywhere and forevermore, to behave in thus-and-such a fashion, then we could extrapolate with confidence. But no compulsion is involved, because there’s no bell, only the ringing. All we have, and all we will ever have, is description.