I suggest that our belief in time and a past arises solely because our entire experience comes to us through the medium of static arrangements of matter, in Nows, that create the appearance of time and change. Geologists certainly deduced that the earth has an immensely long history from structures frozen in rocks. That is, evidence for time and motion in static form. Our long term memories must also be hard wired in the patterns of the neural network in our brains. Again, we have mutually consistent records in static form. It is even possible that when we see motion the material counterpart of the phenomenon is a pattern of neuronal connections that codes several different positions of a moving object at once, and the appearance of motion arises from their simultaneous presence in one brain configuration. As I have no expertise in neuroscience, I do not want to push this idea hard. I merely want to suggest that the appearance of time arises exclusively from very special matter configurations which we find can be interpreted as mutually consistent records of processes that unfolded in a past in accordance with definite physical laws that involve time. I call such configurations time capsules and take the perfectly conventional realist view that they do exist in an external world. However, I think they may arise in a lawful manner that does not involve time at all. If we take the Wheeler DeWitt equation at its face value, this is what must happen.
JB: That's rather hard to believe.
BARBOUR: I'm more optimistic and I am by no means completely alone in thinking that the appearance of time can arise from an essentially timeless universe. There is a quite long standing regular research program involving at least twenty recognized physicists devoted to the problem. One of Hawking's main papers contributed to it about 15 years ago. The aspect of the problem that most excites me is that it might abolish the dichotomy between laws of nature and the initial conditions that you have to add to them before you can make any predictions. The really interesting thing about quantum cosmology is that it should be in a position to make predictions about the universe which can't be made within classical physics.
Classical physics as it exists now has laws and it has initial conditions. If quantum cosmology really is static, there's no initial conditions. There is no time. You can't set conditions at an initial time. In my view, this means that quantum cosmology is potentially much more predictive. It should be able to predict phenomena like the arrow of time and the low entropy of the universe that in classical physics you would just have to attribute to initial conditions, and just say, well the Big Bang happened to take this form rather than a different form.
This is where I think the strongly asymmetric structure of any Platonia that we use to describe the universe could be highly significant. This possibility does not seem to have occurred to other physicists, but I think it must be relevant. If the universe really is governed by something like the Wheeler DeWitt equation and we interpret it as determining the relative probabilities for the various different possible configurations of the universe to be realized, or experienced, then a major factor in determining how those probabilities are distributed must be the overall shape of the arena on which it acts. But that is some Platonia, in which there is always a distinguished point Alpha, from which the complete arena opens up somewhat like a flower. Surely this structure must put a rooted bias into the game. My conjecture is that this static bias in the structure of the arena funnels the higher probabilities onto the special configurations that are time capsules, which, being more probable, are the ones that we are most likely to experience. The overall structure of the arena is reflected in the experienced configurations and interpreted by us as time and a past. This may seem fantastic, but I think the arguments for a timeless universe are quite strong. If we accept them, then we must look for something really radical and powerful that does put the appearance of time into the universe. The difference between past and future is a massive asymmetry. I believe that it can only arise from some other massive asymmetry, which I find in the structure of Platonia.