Saturday, May 05, 2007

On the Existence of God

I recently started reading An Introduction to St. Thomas Aquinas. It starts with his Summa Theologica where he lays out the logical case for the existence of God. As far as I can tell, he defines God as That Which Created All Things. His prose is as dense as a theoretical math textbook and I was reading it on an airplane. It needs a great deal of meditation to get through, so I might have that last definition slightly wrong.

In any case, all he needs to prove the existence of God is the finiteness of time. That is, every effect has a cause and cause and effect chains cannot go on infinitely. Therefore, there must have been an Original Motive Force which by definition is God.

Thermodynamics and astronomy grant him the finiteness of time.

The existence of life on any planet requires a star nearby to supply energy for biological processes. Our sun will one day burn out. Every sun will. The lifespan of the sun is related to the amount of fuel it has to burn. Without infinite mass, it cannot last infinitely. No star has infinite mass and therefore, the lifespan of the ability to support life in the Cosmos is no longer than the lifespan of the longest-living star whose mass and therefore lifespan is finite. Therefore, the lifespan of life is finite.

Even if there is some cyclic nature to the Universe where the stars and planets eventually contract back into some center and explode again to start the process anew, there will be less of them than there were before because the mass of the Universe is continually declining. For one thing, stars convert mass into energy which escapes into space and for another, black holes convert mass into black body radiation which is useless for being converted back into mass.

That means that with each cycle of Big Bang, the amount of matter spread out into space becomes less. This cannot continue infinitely, therefore time is finite. Lastly, as I understand it, current astronomical calculations show that the Universe is expanding and lacks sufficient gravity to contract and repeat the cycle. Time, the lifespan of life in the Universe, is therefore finite.

God exists.

Update: I know that I've made a hash of both Aquinas and Cosmology, but at least I've managed to find two nice links about the nature of the Universe. Try these.
Skyserver
Space.com

2 comments:

Anonymous said...

A slight correction...

IF the universe goes through a repeated cycle of expansion/contraction then the "mass" does not drop between cycles. The details are messy, but the simplest minded way to understand this is that: 1) Yes, mass is converted to energy during this cycle (through E=Mc^2), but 2) As it all contracts back together, the energy also gets contracted back (as the space itself contracts!), and as the energy contracts together it also gravitates (again from E=mc^2). Net result: the grand total is constant.

You are, however, quite correct that the current best data suggest very strongly that the rate of expansion is above that which can be stopped by the total mass (+energy) of the universe, and is, in fact, accelerating, thus producing no method or cause to stop space from expanding forever.

The issue of our universe being infinite has crept back in, but the low entropy regions appear to be finite, and it would appear that life does have only a finite time to play out.

Anonymous said...

Many years ago in UK, George Steiner did a series on space, science, art, philosophy and so on, [he being a polymath] and two things I remember he said, 'The physicists' ultimate question, why is there something rather than nothing' and 'The purpose of the universe is Mozart'.