Due to popular demand, we’ve decided to revisit the arguments for the existence of God using the book “Handbook of Apologetics” by Peter Kreeft and Ronald Tacelli.
The first chapter of the book goes over twenty different arguments for the existence of God, with the first one being “The Argument from Change”. Kreeft teaches logic at a major university so his arguments are clear, concise and very helpful.
So, here is the article:
1. The Argument from Change
The material world we know is a world of change. This young woman came to be 5’2″, but she was not always that height. The great oak tree before us grew from the tiniest acorn. Now when something comes to be in a certain state, such as mature size, that state cannot bring itself into being. For until it comes to be, it does not exist, and if it does not yet exist, it cannot cause anything.
As for the thing that changes, although it can be what it will become, it is not yet what it will become. It actually exists right now in this state (an acorn); it will actually exist in that state (large oak tree). But it is not actually in that state now. It only has the potentiality for that state.
Now a question: To explain the change, can we consider the changing thing alone, or must other things also be involved? Obviously, other things must be involved. Nothing can give itself what it does not have, and the changing thing cannot have now, already, what it will come to have then. The result of change cannot actually exist before the change. The changing thing begins with only the potential to change, but it needs to be acted on by other things outside if that potential is to be made actual. Otherwise it cannot change.
Nothing changes itself. Apparently self-moving things, like animal bodies, are moved by desire or will—something other than mere molecules. And when the animal or human dies, the molecules remain, but the body no longer moves because the desire or will is no longer present to move it.
Now a further question: Are the other things outside the changing thing also changing? Are its movers also moving? If so, all of them stand in need right now of being acted on by other things, or else they cannot change. No matter how many things there are in the series, each one needs something outside itself to actualize its potentiality for change.
The universe is the sum total of all these moving things, however many there are. The whole universe is in the process of change. But we have already seen that change in any being requires an outside force to actualize it. Therefore, there is some force outside (in addition to) the universe, some real being transcendent to the universe. This is one of the things meant by “God.”
Briefly, if there is nothing outside the material universe, then there is nothing that can cause the universe to change. But it does change. Therefore there must be something in addition to the material universe. But the universe is the sum total of all matter, space and time. These three things depend on each other. Therefore this being outside the universe is outside matter, space and time. It is not a changing thing; it is the unchanging Source of change.
Kreeft, P., & Tacelli, R. K. (1994). Handbook of Christian apologetics: hundreds of answers to crucial questions (pp. 50–51). Downers Grove, IL: InterVarsity Press.