Time

Curious asked:

I am thinking about time and time topics all my free time. But I don’t know what is time correctly. Can anybody help me?

Answer by Jürgen Lawrenz

I would want to ask you what you get out of thinking and reading on this subject matter ‘in all your free time’. You should know more about it than any of us! So I’m really puzzled: What do you expect to be told? I ask this because no-one could possibly give a definitive answer, let alone in a few short paragraphs — most of all because the question needs a background.

Thus a philosopher’s angle on it would conflict with the scientific; the religious angle with the agrarian; the cosmological angle with quantum mechanics; and on the business angle, time is money. One among these many notions seems conclusive to me; but I’m in no position to be definitive about it. It goes like this:

If we assume the universe to be spatially infinite, then it must be temporally infinite as well. Then any conception of time-per-se is automatically nullified, because every segment of time can only apply to whatever our object of study happens to be. On the largest perceivable scale, i.e. far away galaxies, we have a spatiotemporal ‘window’ to which we can arbitrarily attach the vocable ‘now’ because it lasts so long, and then subdivide it at our pleasure. On the smallest perceivable scale there is no ‘now’, because these events occur at speeds that are beyond our imagination, packing billions upon billions of our subdivisions into a single second on our conventional time scales. Somewhere in between these two, are the periodicities which affect us directly, from biorhythms to the patterns of seasons. These rhythms gave birth to our concepts of time in the first place. So time is nothing other than the enumeration on a clock face, of the rhythms of nature by which we are affected.

But this is arbitrary too, as shown by the conflict between the length of a second on our standard clocks and the definition of a second that has recourse to the steady vibrations of a caesium atom. This definition is so accurate, that our clock time has constantly to be re-adjusted, as they move out of synch with each other at alarming speeds!

In a word: ‘Time’ is not an independently existing ‘something’ or ‘process’. It’s a word that means whatever any group of humans using it, define it to be. As such it has utility; but we can hardly extrapolate from here to the universe in the expectation that it will nod obligingly in our direction.