The Argument from Contingency
The basic form of this argument is simple.
1. If something exists, there must exist what it takes for that thing to exist.
2. The universe—the collection of beings in space and time—exists.
3. Therefore, there must exist what it takes for the universe to exist.
4. What it takes for the universe to exist cannot exist within the universe or be bounded by space and time.
5. Therefore, what it takes for the universe to exist must transcend both space and time.
But why should we call this cause "God"? Maybe there is something unknown that grounds the universe of change we live in.
Reply: True. And this "unknown" is God. What we humans know directly is this sensible changing world. We also know that there must exist whatever it takes for something to exist. Therefore, we know that neither this changing universe as a whole nor any part of it can be itself what it takes for the universe to exist. But we have now such direct knowledge of the cause of changing things. We know that there must exist a cause; we know that this cause cannot be finite or material—that it must transcend such limitations. But what this ultimate cause is in itself remains, so far, a mystery.
There is more to be said by reason; and there is very much more God has made known about himself through revelation. But the proofs have given us some real knowledge as well: knowledge that the universe is created; knowledge that right now it is kept in being by a cause unbounded by any material limit, that transcends the kind of being we humans directly know. And that is surely knowledge worth having. We might figure out that someone's death was murder and no accident, without figuring out exactly who did it and why, and this might leave us frustrated and unsatisfied. But at least we would know what path of questioning to pursue; at least we would know that someone did it.
So it is with the proofs. They let us know that at every moment the being of the universe is the creative act of a Giver—A Giver transcending all material and spiritual limitations. Beyond that, they do not tell us much about what or who this Giver is—but they point in a very definite direction. We know that this Ultimate Reality—the Giver of being—cannot be material. And we know the gift which is given includes personal being: intelligence, will and spirit. The infinite transcendent cause of these things cannot be less than they are, but must be infinitely more. How and in what way we do not know. But reason can at least let us know that "someone did it." And that is of great value.
- Dr. Peter Kreeft