I have been long intrigued by the fact that, in Greek, both past and future times can take the simple aspect (action completed at a time, i.e. “he ran”) in the aorist and future tenses, respectively, but that the present tense conveys only progressive aspect (action continuing through a time, i.e. “he was running”). Ultimately, the only explanation is to define the present as the widthless boundary between past and future. Thus, progressive action cannot occur in the present because, as the present occupies no time, it can only encompass an action taking no time, and such an action is inconceivable (as it would then be possible to repeat that action an infinite number of times simultaneously). The past and future, on the other hand, are more than even definite, non-zero periods of time, but are rays, extending indefinitely away from the present. Thus, while an action can continue to both sides of the present (progressive aspect), terminate at or before the present (perfect aspect) or start at or after the present (to which no simple Greek aspect corresponds), no action can take place in the present (simple aspect).
But this definition of the present, while philosophically sound, is unsatisfying for certain practical purposes. Thus, I would like to advance a separate definition, for the purposes of praxeology: the present is that period of time demarcated by (but not including) the last point in time at which one can receive information regarding reality in a certain place and the first point at which one’s action can influence reality at that point. The most startling aspect of this definition of the present is that it is not absolute: such a present is defined only with respect to a certain actor, and has a different extent at different places and with different technology. At the same time, I think that these attributes of the present so defined are useful for certain purposes. While it matters very much to a general in his planning room whether a comment was made five seconds ago or will be made in five seconds, it matters very little whether a given event in the battle happened even five minutes before or after the time of his action, if it would take ten for news of the battle to reach him or for his orders to reach the battlefield. Historically, I think that this well explains the infamous Battle of New Orleans: from our modern perspective, it seems horrible that a battle should take place two weeks after the signing of the treaty, but if one considers the primitive communications available at the time, the two events may well be considered contemporaneous. Philosophical nuances may, in places, have very little bearing on practical reality, and time seems to be one of those instances.