The act of writing my first paragraph lies in the past. I cannot change the past even by editing what I have written. I simply create another part of time past. The fact that a reader will not see the pre-edited script is neither here nor there. The act of completing this paragraph at some point in the future is even more problematical, because I do not yet know for a certainty what I am going to write. I will know that only when it has slipped into the past. In fact, all my thoughts about the future rest on my memories of the past. So tightly are the past and future bound to each other that they seem to be a single entity with the present time somehow sandwiched between the two. So what is the present and where or when does it exist?
Let me narrow the study down somewhat. Each word I type on this keyboard has a beginning and an end. When I type the first letter it slips into the past, whilst the last letter still lies in the future, if it can be said to exist at all. A similar argument applies to a single letter word, except that then I would be dealing with the first part of the letter as being in a different time from the last part of the letter. The point I am arriving at, somewhat laboriously you might feel, is that the present time is infinitely short. 'In the limit', as we say in differential calculus, time tends to zero. That is to say, the present time ceases to exist anywhere, or anywhen.
Now here is the paradox. I do not exist because the present time does not exist. By definition, I do not now exist in the future, nor did I exist in the past which was simply a series of present moments. Yet I am here, and have been here! In other words there is an awareness of a subjective present, which is of variable length and coexists with a non-existent real present time. Of course I would accept that there may be a problem of logic involved here, and logic does not always allow one to arrive at correct, that is reasonable, solutions. There are two other possible explanations that can be brought to bear on this problem.
The first explanation is that when we are dealing with time, we are simultaneously dealing with conscious awareness, and that can only be seen through the medium of the ego which is a flawed state anyway. The state that sees more truly is the Higher Self, or that to which we choose to give that name. And it is said that the Higher Self is eternal, not everlasting which implies time passing indefinitely, but eternal, which is timeless.
The second explanation, which is admittedly of a more frivolous nature but not a jot less spiritual, is that currently (we will not allow the word presently) Lucy and I are celebrating our wedding anniversary, and that is always likely to jumble one's wits, especially when a marriage has been as happy as ours. And there I will stop before I slip into an insane, mental timewarp.