Arcadian Functor

occasional meanderings in physics' brave new world

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Marni D. Sheppeard

Thursday, January 25, 2007

The Time Machine II

In Book XI of The Confessions, St Augustine (354-430) investigates the perception of Time in his mortal attempt to understand the eternity of God. He was the first philosopher to appreciate the special significance of the present in a world of measurement, so I will quote him at some length:

"Who shall hold it and fix it, that it may rest a little, and by degrees catch the glory of that everstanding eternity, and compare it with the times which never stand, and see that it is incomparable; and that a long time cannot become long, save from the many motions that pass by, which cannot at the same instant be prolonged; but that in the Eternal nothing passeth away, but that the whole is present...

Thy years are one day, and Thy day is not daily, but today; because Thy today yields not with tomorrow, for neither doth it follow yesterday. Thy today is eternity; therefore didst Thou beget the Co-eternal, to whom Thou saidst, "This day have I begotten Thee." Thou hast made all time; and before all times Thou art, nor in any time was there not time...

What, then, is time? If no one ask of me, I know; if I wish to explain to him who asks, I know not. Yet I say with confidence, that I know that if nothing passed away, there would not be past time; and if nothing were coming, there would not be future time; and if nothing were, there would not be present time. Those two times, therefore, past and future, how are they, when even the past now is not; and the future is not as yet? But should the present be always present, and should it not pass into time past, time truly it could not be, but eternity. If, then, time present - if it be time - only comes into existence because it passes into time past, how do we say that even this is, whose cause of being is that it shall not be, namely, so that we cannot truly say that time is, unless because it tends not to be?

...Behold, the present time, which alone we found could be called long, is abridged to the space scarcely of one day. But let us discuss even that, for there is not one day present as a whole. For it is made up of four-and-twenty hours of night and day, whereof the first hath the rest future, the last hath them past, but any one of the intervening hath those before it past, those after it future. And that one hour passeth away in fleeting particles. Whatever of it hath flown away is past, whatever remaineth is future. If any portion of time be conceived which cannot now be divided into even the minutest particles of moments, this only is that which may be called present; which, however, flies so rapidly from future to past, that it cannot be extended by any delay. For if it be extended, it is divided into the past and future; but the present hath no space...

And yet, O Lord, we perceive intervals of times, and we compare them with themselves, and we say some are longer, others shorter. We even measure by how much shorter or longer this time may be than that; and we answer, "That this is double or treble, while that is but once, or only as much as that." But we measure times passing when we measure them by perceiving them; but past times, which now are not, or future times, which as yet are not, who can measure them? Unless, perchance, any one will dare to say, that that can be measured which is not. When, therefore, time is passing, it can be perceived and measured; but when it has passed, it cannot, since it is not.

...In whatever manner, therefore, this secret preconception of future things may be, nothing can be seen, save what is. But what now is is not future, but present."

3 Comments:

Blogger L. Riofrio said...

Beautiful quote. Cosmologists from Copernicus to Lemaitre show that there is no conflict between religion and scientific inquiry.

January 25, 2007 2:45 PM  
Blogger CarlBrannen said...

Yes, a beautiful quote. I'm taking another dive at learning category theory, this time at wikipedia. You might contribute something there.

I just added the example of Dirac spinors to the wikipedia article on spinors. If you're curious as to how a density operator type guy introduces spinors (as compared to the intro you saw in school), do read. And if I've put in an arithmetic error, do correct.

January 25, 2007 11:01 PM  
Blogger Child_god said...

Nice quote. It's refreshing to read something that I've only expressed in deep thought.

January 26, 2007 5:28 AM  

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