In a previous blog entry, I quoted from The Anthropic Cosmological Principle, and today, I’ll look at something else in the book, since it’s a really fascinating book with lots in it (though you don’t have to have read the previous post to understand this):

From The Anthropic Cosmological Principle by John Barrow and Frank Tipler (1988):
“Unified theories also show us why we observe the World to be governed by a variety of ‘fundamental’ forces of apparently differing strengths: inevitably we must inhabit a low-temperature world…and at these low energies the underlying symmetry of the World is hidden.”

Before getting into the real idea of this, this picture gives the basic idea of what we'll be looking at:

Cutlery aside, there are four known forces in nature: gravity, the electromagnetic force, the weak force, and the strong force. Although they usually seem to have very different effects on the substances they act upon, in some circumstances, these forces can be united. For example, I’ve already called the electric and magnetic forces a united “electromagnetic force,” which is because what on large scales looks like two forces is in reality just one. This is evident at small scales when you go down to the level of particles or in certain circumstances on larger scales. For example, there are electromagnetic waves (photons, or particles of light, are a kind of electromagnetic wave), whereas on larger scales, we usually see different aspects of electromagnetism with, say, magnetism in a bar magnet and electricity in the powering of our houses. Other forces also exhibit this underlying unity. The electromagnetic and weak force are often just called the “electroweak force,” representing a further level of unification at higher energies.

The key point to remember is that higher energies mean smaller scales: so if you go inside atoms and probe fundamental particles, that will be at higher energies and temperatures than, say, the energy of a baseball flying through the air, despite the fact that it’s a lot bigger. Early in the history of the universe, energies and temperatures were much higher than they are now, and that is when these forces would be truly unified. This might be easier to grasp if you think of nuclear fusion and fission: there’s a lot of energy stored up inside atoms, as we can see with nuclear bombs that use only a small amount of matter but release huge amounts of energy.

In many physics theories, these are only the first hints of what is known as grand unification, which is not, as it sounds, some political scheme for world domination, but the unification of the physical forces at high enough energies. The ideas is that at low energies, we see these forces as separate, just like with, say, electricity and magnetism, but as you go up to higher energies, which represent smaller scales and smaller particles, these forces unite. Although we haven’t observed it yet, this means that the strong force will also join forces with the electroweak force to form a single “grand unified force” (“electrostrongweak”, perhaps?) at energies of about 10 to the power of 16 GeV (a GeV is a giga-electron volt. It’s big, let’s just say. And 10 to the power of 16 is 10 followed by 16 zeros. Also big). There are many different theories that can realize this unification, and they are all called Grand Unified Theories, or GUTs. This can be seen in terms of group theory: for example, the electroweak force is called a SU(2) x U(1) and the strong force is SU(3), so combining them gives SU(3) x SU(2) x U(1) = SU(5).*1 That’s not so important, but what is important is that this SU(5) force acts as its own force, not simply a patchwork of the other forces, but something different entirely. This is the hidden “underlying symmetry” mentioned in the quote: although, fundamentally, all forces are the same, they split up when the universe cooled to lower energies and so we usually observe them as distinct, whereas they are actually united, forming a larger symmetry that we can now only observe when we collide particles at very high energies to recreate conditions similar to the early universe.

As can be seen in the picture above, the three forces converge at high energies.*2  This means that their strengths become equal, and we can see them as being the same force. The strong force, then, decreases in strength as you go to smaller and smaller distances, whereas the electromagnetic and weak forces increase in strength until they meet up.*3 This is very important because if the strength of the strong force didn’t decrease, it would never meet up with the electroweak force and would never be united.

Gravity, however, is a slightly different story. The electromagnetic, strong, and weak forces all act on very small scales (of course, we observe electromagnetism on larger scales too, but it’s also very strong on the scales of elementary particles), but gravity is usually negligible for elementary particles, because it is so weak (weaker than the weak force, even). But at very high energies, at what is called the Planck scale (10 to the power of 19 GeV), it is thought that gravity will also be united with the other three, forming not a GUT this time, but a TOE (a Theory of Everything). Of course, even if we are able to work out a theory that united the four known forces, that doesn’t mean that we’ll have a TOE: there may still be many things left out, such as other forces, other dimensions, souls, etc. But uniting gravity with quantum mechanics (the other 3 forces that act on a small scale) would certainly be a big step forward.

So that’s the basic physics idea behind GUTs and TOEs. But if we take it a step further, it could be possible that this is only a small segment of a larger process that occurs in the universe. Take one of our “separate” forces, say, the strong force. What if that force is really the unification of other forces that have already merged? It would then be a more basic force than they are, but would split when the universe cooled to lower temperatures. You could go the other way around too. After gravity, when you have your TOE force (sounds awful, I know. I’ll call it the Everything-1 force, or E-1), there could be other forces that could merge with it too. So as you go to higher and higher energies, ones that are hardly imaginable now but that we may reach in the future, you could get an Everything-2 force (E-2), then an E-3 force, and so on.

This could also tie into the notion of higher dimensions, whether physical dimensions, such as adding a new “direction,” or a spiritual dimension that encompasses a higher level of existence, like a more enlightened state where things are less bounded by restrictions imposed by matter. What appears to be many forces here can in fact be united under a universal law when you are at higher energies or some form of higher state. As usual, the analogy of the glass prism works perfectly here: you have a very basic force that acts on everything, say E-100, and that splits into multiple forces as you go to lower levels of being, just like white light is split into colours as it passes through a prism. All the more particular forces, like all the colours, are all just aspects of E-100, but won’t be united unless they pass back through a converging prism that reunites them.

This ties right into Plato’s Forms: the more complex Forms derive from simpler ones that are more fundamental. These continue splitting as you go to lower levels of existence until you reach the world here, where there are particular objects that partake in many of the individual Forms. To reach enlightenment, one must ascend to higher levels of existence and eventually become one with the higher Forms. This is common in Neoplatonism, where the goal is to ascend to the One, which is the highest level of being. This can also be seen in Buddhism: the more enlightened one becomes, the simpler one’s existence is. Matter is much more complicated than the Forms, and the lower Forms are much more complicated than the higher ones of, say, Number, Symmetry, Beauty, and Motion (for instance, a moving baseball is much more complicated than Motion in general, because Motion is not a particular motion, but the source that all instances of motion derive from). In understanding and becoming in tune with the higher Forms, you can return to the source of all those levels of existence below you and be able to understand them in a unified way rather than as fragmented from one another.

So from a philosophical point of view, the ideas from GUTs and TOEs belong to a more universal pattern of getting to a more fundamental source, whether that is a more basic physical law or a higher spiritual existence, and thus, it will hopefully lead to a more comprehensive view of our universe. But the question is, where does it stop?

*1 There are other options too, such as SO(10), but that’s not important for the concept here. For those who are interested, S = Special (determinant for the matrices in the group = 1), U = Unitary, O = Orthogonal, and the number in brackets is the order of the group. So you have 2 x 2 special unitary matrices in SU(2).

*2 The picture is slightly deceptive because it doesn't show electromagnetism and the weak force uniting before converging with the strong one.

*The reason that the electromagnetic force’s strength is greater at smaller distances is because of virtual particles. Electrons can emit virtual photons that can then turn into positron-electron pairs (a positron is an anti-electron). The positrons, being of a positive charge, are attracted to the original electron and screen its charge by cancelling some of it off with their positive charge. At larger distances, there are more of these pairs, and so the force is screened more, but as you get closer and closer to the electron, there is less screening, and so the strength of the force increases on smaller scales, which is at high energies.


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