I expect you've heard of a few of these "proofs." For example, everything must have a cause. But an infinite chain of causes is impossible. So, at the start, there must have been an Uncaused Cause who is God. God is, as we say, the "Unmoved Mover."
Again, you've likely heard this argument before. And yet, many scholars would argue that the summary of the argument I made above is actually a misunderstanding of Thomas' argument. It also misunderstands how steeped in apophatic mystery are Thomas' "proofs," which is why I'm putting the word "proof" in scare-quotes. Basically, there's a whole lot of confusion, among both Christians and atheists, about what Thomas is doing with this five "proofs" for the existence of God. Because of this, I'd like to share some clarifying thoughts in this series.
But before I do that, let's today review Thomas' five arguments. The ones I want to focus on in this series are the first three arguments, two of which famously appeal to "infinite regress." Here's ChatGPT's summary of the those first three arguments:
The Argument from Motion: Aquinas observed that objects in the world are in a state of motion. He argued that for something to be in motion, it must have been set in motion by something else. However, this chain of motion cannot go on infinitely because there must be a "First Mover" that initiated the motion. Aquinas identified this First Mover as God.
The Argument from Efficient Causes: Aquinas considered the cause-and-effect relationships that exist in the world. He claimed that every effect has a cause, and this chain of causation cannot go on infinitely. There must be an ultimate "Uncaused Cause" that set everything into motion. Aquinas identified this Uncaused Cause as God.
The Argument from Contingency: Aquinas argued that everything in the world is contingent, meaning they depend on something else for their existence. He reasoned that if everything were contingent, then at some point, nothing would exist because there would be nothing to bring contingent things into existence. Therefore, there must be a necessary being—an entity that exists by its own nature and does not depend on anything else. Aquinas identified this necessary being as God.