- Can you inform us about the four fundamental forces of the universe and the balance between them? Who possesses the faculty and knowledge that gives rise to these forces?
- The four fundamental forces has been really a story of progress of unifying different things together.We typically talk about gravity as one of these forces. About the electromagnetic which is magnetism and electricity. And then two nuclear forces, the weak and the strong force. Actually, that’s been a story of unification, so it’s used to be that magnetic and electric forces used to be completely separate. And then with Max’s equations in 1800s, those two were unified into one, which is what we call the electromagnetic force. Then later on in the 20th century, the weak nuclear force was unified in with the electromagnetic force. So people talk about the electroweak force and so then we are down to three. And then now with the standard model, which we talked about before, the strong force and the electromagnetic and the weak forces are now unified. So in some ways, you could talk about two forces: the standard model, and then the gravity as being the one which is left out. It is not at all clear how to bring gravity into that picture. But one of the things I would say that has bothered people about the standard model is again this presence of tuning parameters. Parameters that are not required by the theory but have to be just right to match what the experiments are. So this gets back to the aesthetic issues of physics. Initially think about history going way back, we have five elements, air, fire, water, and so on, very simple. Once people started doing chemistry, they found more and more elements. And so, you know there is gold and lead and so on. And eventually by the end of 1800s, we had hundred or more elements. And that just seemed too many for people;like why should there be so many elements.And so they started to seek for a way to unify those things and,lo and behold, they came up with the nuclear theory, which then looked simple at first:just protons, electrons, and neutrons, just three types of particles.And that seemed very nice.Then they continued to do nuclear physics and found that there are actually now hundreds of types of nuclear particles, not just three. Neutrinos, kaons, pions and so on… Once again it looked ugly. 3 somehow is appealing, but 246 seems not aesthetically appealing. Once again they found a way to unify these into the standard model and quarks and gluons. At first, there was a feeling that this would be very simple, that we would have just three colors of matter and we’d unify everything again. But once again with the standard model now we have something like 17 types of particles, each with different coupling constants and forces between them. For many people, it looks like too many, it doesn't look pretty. At every stage along the way, what you see is we have tuning parameters;things that seem to be arbitrary parameters. And I would say that many physicists have the desire to have a parameter-free theory, where everything is just required to be the way that it is by pure logic. And what we see experimentally is that seems to be not the case, that in fact there are these tuning parameters what we can call design parameters.In theological terms, you could say what many physicists want to do, and actually Einstein said this explicitly, was,he said that he would like to prove that God could not have created the universe any other way[surely God is above that]. What we see actually is that God, as far as we know, could have done things differently, that all of these parameters are free parameters, and they are design choices that were made in making the universe the way that it is. So I just think eventually no matter how far we go, we will still see that there are these design parameters, that are free choices of God that are not required by any kind of logical necessity or geometry or things like that.
