The title to this post is also that of one of my favorite Miles Davis tunes. It means, of course, "time flies" but may have been derived from a line in Virgil's Georgics--Fugit Irreparabile Tempus. That line has a darker meaning. Time passes swiftly, and once it passes, is irretrievable.
The past is the great and inaccessible storehouse of our lives, and contains all our mistakes, our achievements, our actions, thoughts, and too often loved ones and friends. It is the quintessential thing not in our control; there's nothing we can do about it. Yet it haunts us, rides us like a hag. It also, though, has made us what we are. If we can control ourselves, why can't we control our past?
Well, because it's not here, though we are. What we may say, employing metaphor, "made us" need not be here with us. We remember the past; we don't possess it. Remembering the past doesn't consist of living the past. We did that already. We can, in a sense, repeat the past, which is merely to say make mistakes we made before.
Just what the past consists of is, like so much else it seems is apparent, a subject of philosophical debate. I doubt if it can be intelligently claimed to be anything but things that happened. Nobody thinks the past is taking place now; nobody confuses it with what takes place now. There seems little need to debate this, but it has been made a subject of debate. The past isn't the books, films, sounds about the past we read, see and hear. Again, this is an obvious conclusion. We know the past can be misrepresented. So can what takes place now. There is no reason to believe the past is or is not exactly what common sense indicates is the case. For some, of course, this only makes it a more attractive subject for consideration, common sense being prima facie deficient to certain of us.
The past is a concept regarding which I think it would be useful to apply the pragmatic maxim: "Consider what effects, that might conceivably have practical bearings, we conceive the object of our conception to have. Then, our conception of these effects is the whole of our conception of the object."
Peirce, the maker of the maxim, seems to have reconsidered it over time, and there have been those who have different ways of looking at it just as Wallace Stevens noted we may have thirteen ways of looking at a blackbird. But it appears to me that Peirce thought of it most consistently as a method by which to make ideas clear; particularly ideas that are bandied about in philosophy.
The "past" has practical bearings to the extent it is thought of, studied, used by us, here and now. There are various ways in which it can have practical bearings, on us and on others and on the rest of our world, which is to say that it has consequences. There is no need that it be defined any further than that requires. To the extent we define it otherwise, we're engaged in flights of fancy. Such flights of fancy usually involve our tendency to think in terms of things. Thinking of the past as a thing naturally leads one to treat it as a thing, an object regarding which we speak.
What has practical bearings is not the thing which is past, it's what happened in the past and its effects we encounter today.
We need no flights of fancy in order to acknowledge the significance of the past. The past is hugely significant, as it effects how we think, feel and act. Our past, though, is in particular irretrievable and because it necessarily involves things we did or did not do, those we knew but no longer see, it is inevitably a source of regret though it may also, sometimes, be a source of be a source of fondness. There are good memories as well as bad. But we humans tend to do or not do more that we regret than we are proud of, and when we regret what we did or did not do that regret arises from our sense of responsibility.
What's done cannot be undone. This is the tragedy of the time-bound. We can't avoid the mistakes we've already made and the consequences of those mistakes can only, at best, be mitigated.