The Physics Phenomenon

There is a curious effect when people, usually non-physicists, write about physics. They tend to land up talking about particle physics and cosmology as if they were more or less the same thing and also the only really interesting bits of physics (or worse, science in general) that there is. Now undoubtedly cosmology and particle physics are interesting. They are the realms where the very big and the very small meet. Often, the interest is in the ‘fundamental structure of the universe’ (whatever that means), and, somehow, that links to our interest in who we are and what we mean by it.

I have just read the physics section of A. C. Grayling’s The Frontiers of Knowledge. Leaving aside his occasional swipes at theism (I suspect it gets worse in the sections on history and psychology) he does focus on exactly these two areas of physics, even though he is to well informed to think that these are the only areas of science worth thinking about.

Nevertheless, most popular physics does the same thing. Quantum mechanics and the theories of relativity are weird, counter-intuitive. Trying to explain them and then discuss the implications without a single equation is difficult, to say the least. Grayling does a good job, on the whole, with only a few slips (the photoelectric effect does not depend on the intensity of the light shone upon it, but the frequency – I am sure that is a slip, and there seems to be some confusion about Planck’s constant).

The interesting thing about the section is not the summary of modern physics (in the sense of cosmology and particle physics) but the various understandings of what it might mean for us. Grayling describes several problems, which might best be described as philosophical. For example, the pinhole effect means that, as humans, we look at the universe through cognitive equipment designed for our scale – somewhere between the very big and the very small. That means that the very big and the very small do not behave in ways that are intuitive to us. Perhaps the surprise is really that we can, with the aid of mathematics, describe these realms at all.

But mathematics is another rub, perhaps. Why is mathematics so successful in describing the universe and its phenomena? Physics is a mathematical science, after all, although physics is not mathematics. Much of physics consists of describing a phenomenon through an equation, solving the equation, albeit approximately, and then seeing if your result bears any resemblance to the real world.

And here is the next rub, I think, and one which perhaps is not pondered enough by more popular physics writers. Much, if not most, physics is the art of approximating. Cosmology and quantum physics have a tendency to look at ‘pure’ systems. Thus we can quest for a ‘theory of everything’, where all forces are contained in one neat, clear, and concise formula. The idea is that the mathematics gives us something that is, in terms of mathematical aesthetics, beautiful. It would be, of course, highly abstract and, probably, only a few highly trained mathematical physicists would understand it. But some would claim that we had solved the universe.

The problem here is that once we are even slightly away from highly abstract theories of everything, physics rapidly gets messy. Approximation aboud, and there is not alternative but to make them and then refer back to the real world, though experimentation, to verify the results we obtain by calculation. This is true as well of cosmology and particle physics, but the theories tend to race off towards the unverifiable horizon quite quickly, and some of them never seem to return.

That does not mean to say that theories of everything will remain unverifiable, but it does say that they might not be terribly useful in more everyday physics. It is entirely unnecessary to consider the composition of protons while understanding the structure of the hydrogen atom. Quarks and gluons have no impact on solid-state physics at all. Yet these subjects are important parts of physics, and, probably, more physicists work on them than work on the fundamental structure of reality and the universe in general.

This might, of course, be part of the general oddness of the human race, or at least those parts of it which consider such things. Many a late-night undergraduate session was (and probably still is) fuelled by a few beers and a discussion of the true meaning of quantum mechanics. Richard Feynman dismissed such issues, arguing that we should just shut up and calculate. The theories work and produce verifiable numbers; why worry about what the theories mean?

That is not where most people who think about it are at. Grayling describes a number of the issues which do come about. Perhaps mathematics and human cognition are so closely linked that we can only see patterns in nature that are mathematically describable. Perhaps Kant was right when he argued that we see nothing as it is in itself, but only can describe the phenomena, that everything is only describable, ultimately, in relation to the human and to human cognitive structures.

Perhaps, but physics does allow us to describe, albeit only partially, things in relation to each other – the interaction of billiard balls, perhaps. In principle, there is no human required to be present. A ball enters, hits another one, imparts a certain quantity of energy and momentum, and the balls go their separate ways. Except for the measurement of the initial and final states, there seems to be little role for the human here. The universe is clockwork.

And so, roughly speaking, we are back to Berkeley’s challenge. Is the world a product of the human mind or not? If not, is the world a product of the mind of God, and, again, if not, how does it manage to be? If the universe is only material how come it is so complex? And, perhaps, how come it has developed intelligent life (well, fairly intelligent life) to observe its complexities, albeit only partially?