Another Theology Blog

St. Thomas Aquinas once argued that we can’t know whether time had a beginning, or in other words, whether the world has always existed.  I’m convinced that I’ve managed to prove the Angelic Doctor wrong on this point.  I know I’m making an extremely bold claim, but please consider my argument.

Suppose time has no beginning. Then there must be, by necessity, infinite moments prior to the present. However, in order for the present to exist, all of these previous moments must have already passed in orderly succession, one right after the other. This is impossible, because infinity is not traversable.

In other words, the present moment is like a step on a staircase. In order to get to it, we must first climb each step below. However, if there are infinite steps below the present moment, then we will never finish climbing them, and thus we will never arrive at the present moment. But we are indeed, right now, at the present moment. Thus, the staircase must not extend backwards into infinity.

Therefore, time has a beginning. There is no other alternative.

I concede that there are some weaknesses in the way I originally phrased my argument, but thankfully, westmarked showed up and clarified everything considerably.

Let me see if I can phrase the argument a bit differently:

If we posit that time has a beginning, but no end, then it could be said that time will go on infinitely into the future. But at no time will we ever reach “infinity”. At any given point there will have been a finite number of seconds, minutes, years, centuries. At any given point we could say, “it has been X long since Y occurred (including the beginning of everything)” and that X would never equal infinity. It might be 9.34542 x 10^13229, or some other astoundingly large and to the human mind inconceivable number, but it will always have been a finite amount. Thus, even though time has no end, there is never a point where it will have been infinitely long since the beginning of the world. At any given point, there will have been a finite amount of time.

In this case, “infinite” does not mean “uncountable” in reference to human ability. It means, literally “a number larger than which cannot be conceived”. (Thus, infinity, technically, does not exist outside of being a theoretical construct, because there is always a large number one can think of.)

If the world had no beginning, however, then we are forced to say, as you state, that an infinite number of events/seconds/whatever have happened before this point. But it is equally true to say that an infinite number of events happened before 10 seconds ago. But this does not mean that 10 seconds ago infinity had passed and now infinity+10 seconds have passed. There is no such thing as infinity+10. 

To continue: If there are an infinite number of events before the present, there are also an infinite number of events before 10000 BC. And before AD 802,701. So why are we here in the twentieth century, rather than running herds of mammoths down the sides of pyramids, or being frolicking, feckless Eloi? The same amount of time–infinity–has passed between each event and the “beginning”. But this is meaningless. If the world has no beginning, this means that it would have taken us forever to reach this point. But it would have taken us forever to reach any other point in history too. This also is meaningless.

One of the things they teach early in math is that you can’t divide by zero. Dividing by zero means you can create equations that result in 2=1 (I’ve done this) or 65=-4, or whatever else you want. The same sort of situation comes into play whenever you try to treat infinity as a number that can exist in the real world. Positing that the world has no end does not run into this problem, but positing that the world has no beginning does.

The conclusion?  Everything that was made had a beginning, including the universe.  This is because created things necessarily have motion (from potentiality to actuality), and an infinite regress in motion entails an infinite regress in temporality, which makes about as much sense as a square circle or a true falsehood.

Of course, the above argument can also be used as an argument for the existence of God.  Just by observing the nature of time (all previous moments have passed in orderly succession before the present), we can conclude that an infinite past is impossible.  Thus, the world had a beginning; indeed, there is no possible way for it to be eternal.  We are now face to face with the Almighty, the Eternal Cause of the non-eternal world.

“In the beginning God created the heavens and the earth…”