As formulated by Thomas Aquinas, the unmoved mover argument is stated as follows:
- "Nothing moves without a prior mover. This leads us to a regress, from which the only escape is God. Something had to make the first move, and that something we call God."
This argument is one of the Quinque viæ, "Five Ways", or "Five Proofs".
Many of the responses to the "uncaused cause" argument also apply to this one:
- If nothing moves without a prior mover, then God must need a prior mover, as well. Otherwise God is nothing, which contradicts the conclusion. Thus, either the premise is untrue, in which case the argument is unsound, or the conclusion doesn't follow, in which case the argument is invalid. In fact, as stated, the argument is clearly self-contradictory.
- Who created God?
- Which god? The argument does not demonstrated anything like a God. The arbitrary use of the word "God" in the argument carries a lot of undesirable cultural baggage, denoting an intelligent being. If the ultimate cause of our universe turns out to be, say, a random quantum fluctuation, then that would be "God" by Aquinas's definition, but to call this phenomenon "God" would be very misleading.
- Two bodies at rest will start to move towards each other due to gravity. They can be each other's first mover. Therefore, the prior mover requirement is unnecessary.
- Pairs of virtual particles are created (and annihilated) all of the time, out of literally nothing. These particles affect each other's motion, thus disproving Aquinas's premise. Not all events necessarily have causes.
- More exotically, if time were circular (i.e., if time repeated every so often, so that the year 1 were also the year ten trillion and one), then every motion could have a prior cause without infinite regress. This does not seem to be the case, though.
- Even if there is an infinite regress of causes, so what? The human mind is uncomfortable with the concept of infinity, but reality has no obligation to make us comfortable.
- Thomas Aquinas and the First Mover Argument, BBC Radio 4