The Cosmological Argument for the Existence of God

Sometime last month, I wrote about why the ontological argument for the existence of God perplexes modern thinkers. I argued that modern thinkers exploit a conceptual ambiguity in the way the word existence is used. Everyone agrees that God does not exist in the same way a computer monitor, a tree, a person, or any other object found within the realm of possible human experience is said to exist. Not everyone agrees on what this implies. An atheist may very likely say God therefore does not exist. A theist may try to encourage you to open your mind to consider the possibility of another sort of divine existence. And the agnostic may stand back and point out the sheer absurdity of gesturing mentally into the Great Beyond. (Myself, I am partial to the agnostic position, since it does not pretend to get at something 'out there', but concerns itself with the limitations of human knowing.)

What all parties involved appear to agree on is that the ontological argument does not work. The existence of God will not be proved from reason alone. A thought about something, however well-crafted and logically coherent it may be, will never be enough to substantiate the existence of something.

Well, what about arguments from observable, material objects? A second class of arguments for the existence of God that does just that are the so-called cosmological arguments. Saint Thomas Aquinas provides one variation of the argument, from the motion of objects to a First Mover, which, as he famously says, we name God. The argument looks like this:

1) Since everything in motion is moved by some other thing, and
2) since movers and things moved cannot proceed to infinity,
3) therefore, we must posit the existence of an Unmoved Mover, which we call God.

Step 1) is a relatively unproblematic assertion. Things don't just move on their own. Something has to set them in motion. Unless the reader thinks that things in the world inexplicably pop into and out of existence, everyone should be on board thus far.

Step 2), however, is not so clear. What's to stop things from running to infinity? If I know M is proceeded N and N proceeded O, because I observed M proceeding N proceeding O in a causal sequence, what's to stop me from inferring L proceeded M, K proceeded L, and so on, and on, and on into infinity? Or what's to suggest O is not followed by P, Q, R, etc. etc. I already know that things don't just move on their own. So there must be a K proceeding L proceeding M and a Q succeeding P succeeding O...right?

Not quite. In a Newtonian universe, in which cause and effect are analyzed in terms of an ever more complex series of billiard ball movements, this line of questioning make sense. We post-Newtonians tend to think of causal sequences as a series of objects acting upon each other as occurring in a spatio-temporal reality. We also tend to think of movement in terms of a change of spatial location over a periods of time. Hence we measure the velocity of an object in units made up of distance and time, such as 'km/h' or 'mph'.

Aquinas' definition of movement is much wider. A change of location is a movement, just as much as food rotting in fridge is a movement. For, in point of fact, something caused the food to rot. Something moved the food to change from a state of being fresh to being rotten. The technical terms Aquinas uses for movement is the reduction of something from 'potentiality to actuality'. A seed is potentially a tree. If planted in the ground, it may actually become a tree.

It will follow that Aquinas' definition of movement, encompassing all manner of changes, has more to do with why things change in predictable ways. Numerous other examples could be offered in addition to the ones offered above. What determines that state B should always follow state A? One perfectly acceptable scientific answer is that this is just the way things are. There is regularity. Full stop. Instead of inquiring about why there is regularity, we ought to inquire about how that regularity functions. Instead of allowing our thinking to wander from the natural phenomenon into the infinite expanses of things that might be, we ought to train our minds to consider the natural phenomena itself.

Aquinas is not satisfied with simply accepting that's the way things are. He wants to to know why things are the way they are. We have already conceded, you may remember, things don't move themselves. Something caused it. Something moved it. There must be a First Mover, which setting everything else into motion. That's why things are the way things are--with emphasis placed on the unity, universality, and singularity of the are in the way things are.

Aquinas' proof does not fit into our scientific way of thinking about things. The why question wants a speculative rationale for an answer, not reasons grounded in observable evidence. His account of the motion of objects has less to do with the actual movement of objects and more to do with a chain of thoughts in a person's head. Unfortunately what this means is that the cosmological argument runs into the same problem as the ontological argument. In the end it turns out to be an argument from reason alone.