Reading again through Saint Augustine’s “Confessions”: Day 21 (The Past and the Future Do Not Exist!)
“As a boy I learned that there were three divisions of time, past, present, and future, and later on I taught the same lesson other boys. But there might be people would maintain that there are not three divisions of time but only one, the present, because the other two do not exist. Another view might be that past and future do exist, but that time emerges from some secret refuge when it passes from the future to the present, and goes back into hiding when it moves from the present to the past. Otherwise, how do prophets see the future, if there is not yet a future to be seen? It is impossible to see what does not exist. In the same way people who describe the past could not describe it correctly unless they saw it in their minds, and if the past did not exist it would be impossible for them to see it at all. Therefore both the past and the future do exist.
If the future and the past do exist, I want to know where they are. I may not yet be capable of such knowledge, but at least I know that wherever they are, they are not there as future or past, but as present. For if, wherever they are, they are future or past, but as present. For it, wherever they are, they are future, they do not yet exist; if past, they no longer exist. So wherever they are and whatever they are, it is only exist. So wherever they and whatever they are, it is only by being present that they are.
When we describe the past correctly, it is not past facts which are drawn out of our memories but only words based on on our memory-pictures of those facts, because when they happened they left an impression on our minds, by means of our sense-perception. My own childhood, which no longer exists, is in past time, which also no longer exists. But when I remember those days and describe them, it is in the present that I picture them to myself, because their picture is still present in my memory.
Whether some similar process enables the future to be seen, some process by which events which have not yet occurred become present to us by means of already existing images of them, I confess, my God, that I do not know. But at least I know that we generally think about what we are going to do before we do it, and this preliminary thought is in the present, whereas the action which we premeditate does not yet exist in its future. Once we have set to work and started to put our plans into action, that action exists, because it is now not future but present.
But whatever mysterious means it may be that the future is foreseen, it is only possibly to see something which exists; and whatever exists is not future but present. So when we speak of foreseeing the future, we do not see things which are not yet in being, that is, things which are future, but it may be that we see their causes or signs, which are already in being. In this way they are not future but present to the eye of the beholder, and by means of them the mind can form a concept of things which are still future and thus is able to predict them. These concepts already exist, and by seeing them present in their minds people are able to foretell the actual facts which they represent…The future, then, is not yet; it is not all; and if it is not at all, it cannot possibly be seen. But it can be foretold from things which are present, because they exist now and can therefore be seen.
From what we have said it is abundantly clear that neither nor the past exist, and therefore it is not strictly correct to say that there are are times, past, present, and future. It might be correct to say that there are three times, a present of past things, a present of present things, and a present of future things.future things. Some such different times do exist in the mind, but nowhere else that I can see. The present of past things if the memory; the present of present things is direct perception; and the present of future things is expectation. If we may speak in these terms, I can see three times and I admit that they do exist.”