By ROGER PENROSE [interviewed in The Times of India] – What is your opinion about many-universe theories? Doesn’t your new theory suggest multiple Universes?
I am not an enthusiast. There are several different theories of multi-universes. The one I am proposing is sequential. It’s a different scheme. You have multi universes from people who believe that the interpretation of quantum mechanics leads you to what is called the ‘many worlds’ theory, the Everett interpretation. There are many people who like that point of view because it seems to avoid having to contradict unitarity or the Schrodinger’s Equation, or whatever you like to say. I personally don’t think it’s a solution and I think it is not explaining the world that we see, which is what we are trying to explain. It is explaining a sort of hypothetical world in which things branch and we go off in different branches. I have trouble with that. But that’s one multi-universe scheme. Another multi-universe scheme comes from certain discussions of inflationary cosmology. I should say that inflation is not part of my scheme, its an alternative to inflation. So I don’t accept that inflation ever took place. I mean it took place in the previous aeon not after the Big Bang.
But those people who are adherents of inflation sometimes are driven to the picture where in the late stages of the expansion of the universe there is a probability that it would start off again and there are new universes seeded in this. That is another kind of multi-universe theory. I am not an adherent of that.
The third one has to do with what is known as the anthropic principle where it is argued that the constants of nature are so organized that life can exist and if they were a little bit different, life would be impossible. So the picture is that you might have parallel worlds with different constants of nature and life exists in only those few in which the constants of nature are suitable for life. Therefore, we must find ourselves in one of those parallel worlds where the constants are right. I am not happy with that view although it has a greater rationale to it than the other ones, I think.
The main thing that I am not happy about is that I don’t see how we have the remotest idea what would happen in a world where the constants of nature were different because we know the life we know. And there could be life of a completely utterly different kind that we have no conception of.
And it might even be unknowable?
Yes, it might even be unknowable. I don’t know. Okay, there is a role for these arguments but I hate to depend on them. And I think that a theory that depends on them is likely to be limited.