A possible solution of one theory of time-travel

I once heard an objection to time-travel along these lines. It’s physically impossible to travel through time, because there is, at any time, only a select amount of particles in the universe. A thousand years from now, the particles from your nose could be anywhere, in a chair, a tree, an animal, the ground, a cloud. Thus, supposing you did travel through time, a contradiction would arise. The same particles which are in your nose would also, at the same time, be in the cloud or other object they would have been in had the time travel not taken place. But since there is, at any time, only a select amount of particles in the universe, this state of affairs is a physical impossibility. The time traveler would have, simply by virtue of traveling through time, multiplied the amount of particles in the universe, and, without meaning to, would pose a very tricky philosophical problem: how is it that we can say that those particles in the cloud (or any object) are actually particles from the time traveler’s nose? Can, indeed, things be called the same because they share all the same properties, even though they don’t share the property of ‘being in the same place’? Isn’t that another contradiction, a logical one? For these reasons, C.S. Lewis speculates, in his uncompleted story The Dark Tower, about the chronoscope, an instrument that would allow you to see into the future from your present vantage point, just as a telescope allows you to see into distant spaces from an earthly-situated vantage point. The chronoscope would allow you see the future distribution of particles without the particles you presently have being disturbed. Unless we allow the scientific possibility of ‘action-at-a-distance’, the chronoscope seems to be a handy instrument. We wouldn’t be able to mingle with the future or the past, but we’d be able to see it. The problem is that if ‘action-at-a-distance’ is possible, our very distant observations might enact the unwanted consequences we’re trying to avoid: the very phenomenon of our observing the future might affect things so that they would be one way with the observation, and another without. But we’ll ignore this for now.

Recall: time travel is supposed to be physically impossible because if the time traveler did indeed travel, the amount of particles in the universe, which ought to be set, would increase, encompassing now the particles of the time traveler and the future distribution of the particles of the time traveler, had the time traveler not traveled. But supposing a loosely fatalistic universe in which everything that will be will inevitably be, and if things will inevitably be, and the future is already set, then the present distribution of particles might not be what we think it to be. The chasm might not be the metaphysical one in which new particles popped into being, thus interrupting what is supposed to be the fixed amount; it might be the epistemological one in which what we thought to be the fixed amount, isn’t the amount at all. Indeed, if the time traveler does, after all, travel, the universe, which includes all its times, has already, since time immemorial, included such an action. In this way, the time traveler doesn’t introduce into the universe new and before non-existent particles; he only fulfills and brings to fruition a certain distribution of particles, a distribution that the universe already had in mind since its inception. All the time-traveler did was to enact, and put into a certain pattern, the various particles that do happen to already exist. And among these various particles happen to be those that might be what is called ‘temporally indexed’. That is, there are actually particles that exist in the present that are different from their future counterparts. When a particle changes, as we say, from X to Y, X ceases to be X and becomes Y, even, as we must say, that without X, the emergence of Y would have been a physical impossibility. Perhaps, however, present-X stays in the present so that future-Y can come about. In this way, if X travels through time, he is no longer present-X, but future-X. If he is future-X, present-X can linger behind so as to allow the emergence of future-Y. Let present-X, future-X, and future-Y all represent particular distributions of particles. Since all these distributions are unique, their co-existence seems to be a real physical possibility. In this scenario, we avoid the difficulties from before, which lead to consideration for the chronoscope. Here, we’re not saying that there is a state of affairs in the future in which the very same physical particles are in two places at once; we’re saying that, in the future, after the time traveler travels, there are two distinct distributions of particles, future-X and future-Y (which came from past-X, which was then present-X). Future-X and future-Y are kin, not because they are identical, but because they are counterparts, linked together because of their own unique relationship with one another.