This is shaping up to be quite different than what I expected before starting this. Based on what I had read about Aristotle, I had always assumed his unmoved mover idea was entirely about the chain of causes and effects in time, but the argument he seems to be heading toward is that a universe without an unmoved mover would have to contain an actual infinity of matter.
Right—it’s not about a chain of causes and effects in time. Near as I can tell, the familiar “first cause” argument is not actually found in Plato or Aristotle, though they make arguments that draw on some similar cosmological premises. This argument from the Timaeus might be the most similar.
As to an “actual infinity of matter,” that’s one possibility. The other is that there might be an infinite number of divisions, containing infinite movements, which occur at the same time. Very weird.
I don’t know if this analogy goes, but it’s like seeing a long queue with the last person in line (A).
1. Assuming the line is infinite
2. We see A moving 100 steps in an hour (it’s a Disney World queue 🙂 )
Conclusion: an infinite line moved 100 steps in an hour. This is impossible, therefore original premise is false.
That’s a rough analogy, but there are big disanalogies…which you probably know. It’s not about the rate of movement but about the possibility (or impossibility) of an infinite set of movements occurring within a finite body. More importantly, it’s not about infinite sequential movement (which is what you would expect in an argument that concludes “there must be a first mover”) but concurrent movement.
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