What happens when a photon moves from one place to another, for example in the double-slit experiment? It seems that the universe splits to two separate universes (or more generally speaking, to an infinite number of universes), each of them contains one possible option, and then merges again into one universe. When a universe splits, each universe will contain a photon who will remember its past but will not be aware of the other photons in the other universes. When universes merge, the photon will remember a combination of pasts and not only one past. Universes split and merge all the time. In areas of spacetime where there are more splits than merges, spacetime and entropy increase in time. In areas of spacetime where there are more merges than splits, spacetime and entropy decrease (and time goes “backwards”).
For any two given events in spacetime, the question whether one of them happened before the other one doesn’t have a deterministic answer – it depends who you’re asking. Deterministic logic proves itself to be inconsistent, so I will use nondeterministic logic, which can be seen as probabilistic logic too. Any two events in spacetime in any two universes can merge and become one universe, no matter how far they seem to us according to our imperfect logic. Illogical things appear to exist as well (of course, it depends how we define “illogical”). The speed of light is not constant, and therefore can be any speed. Light can go forward in time, or backward, or be at two places simultaneously.
Spacetime and entropy are just illusions. Imperfect assumptions. Everything can happen, and everything does. The number of universes is infinite. It is not a number, it’s a perception. All the universes can be interconnected sometimes, sometimes not. Other galaxies might be our galaxy from different angles or in the past or more generally speaking in different areas of spacetime. It’s like entering a room full of mirrors, and see infinite images of yourself from different angles. You can’t look too far, because light fades and some images are hiding other, more distant images.
Spacetime and entropy are how we perceive reality. We define “past” as the direction where there is more order, according to our perception, and therefore we can “remember” things in the past. The future is things we don’t remember, we don’t know for sure. But we can still make assumptions, and if we look at the past, we will see that some past assumptions appear to be true (according to our imperfect logic). There is no one past and one future, the number one (or any number) as a constant number doesn’t exist. The numbers of pasts and futures change all the time. In the future we will find out that some of our assumptions were true, some not, or actually – we will find out that any assumption is true or not.
The concept of “I”, as a single entity, doesn’t exist. There is no one “I” in the past, nor in the present, nor in the future too. There are infinitely many of them. If I met you tomorrow and then meet you again today, neither you nor I are the same people. We share some memories, some memories we don’t. But since we live in an area of spacetime where entropy appears to increase in time (that’s how we define time) and spacetime doesn’t shrink or expand too quickly, we find out that most of the time deterministic logic works well. Contradictions appear to be rare, although they do exist. Some people say they saw things which appear to be illogical. Nothing is illogical. Everything is possible in nondeterministic logic. Everything can exist.
Space, time and the speed of light are created by the entropy assumption – the assumption that particles are separate entities and therefore interact with each other in a probabilistic way. Their decisions are assumed to be independent, and this is true most of the time. But if two events in space are connected and occur at the same time (according to our definition of space and time), the speed of light between them can be infinite. When this happens, entropy decreases and we go backward in time.
Actually, the direction we go in time is not “forward” or “backward” but the number of directions is infinite. There are no roads not taken – we take all roads. When an object travels in spacetime, his time goes in a different direction than ours. Since nothing is deterministic, when he comes back he might remember things we do not. He might even see us in future – one of the futures – but there are many possible futures. Our future might turn out to be different than his.