That was dense, I’ve read the text and this answer multiple times.
In conclusion “What we have yet to discover is whether, and why, it matters that no object moves itself taken as a whole.” Applying this to the prime mover, if we say God does not move himself as a whole, but there are parts of God that do the moving, and other parts that are being moved, does that introduce a problem of regress? I guess we can ask which part of God caused him to move, and which part caused that part to move, ad infinitum. So instead of making God the starting point of all movement, we continue the regress by dividing God into smaller and smaller parts.
Furthermore, does God actually move himself? He moves things in creation but moving himself is another thing altogether. I thought God does not change, he does not grow from potential to actual, surely he is fully actualized from day one. Is that where we will be heading? Looking forward to tackling some of these ideas.
That is an exhausting passage to dive into deeply. Your discussion of the meanings of essentially and primarily was especially helpful. I had glossed over those words a bit in my own reading, and was having trouble figuring out how he wasn’t contradicting himself.
Everything that is in movement must be moved by something. That something is either something external or something internal. I think the external one is more obvious and probably why he doesn’t spend much time on it. But this internal one, self-mover, is the more interesting one. This dividing principle seems to highlight that even within a self-moved whole there are parts that are moved and parts that initiate the movement. I keep trying to find a metaphor for all these movement parts, but none really work. I was thinking of a car as a whole being the self-mover, and then dividing it into parts like engine and wheels. But, then how does inertia work in that case? Engine can stop by inertia can still make wheels go for a while. Also, I am not sure I understand how “what is in movement will always be divisible”. There does seem like that’s not always the case.
Wow! That was quite dense.
Craig’s summary is impressively crisp, even though I agree with Larry’s objection.
Btw, the analogies (car/motor, person/legs) really helped my understanding of the argument.
I definitely haven’t fully grasped the text here yet, but what I do see is how Aristotle differs from Plato regarding the idea of self motion. He points out that the things that might be called self movers can be divided into parts, and certain parts are responsible for moving the others. To give a simple example that sounds less like algebra, if I’m walking around, it’s my legs doing most of the physical work of moving the rest of my body, but ultimately my legs didn’t start moving of their own accord, but rather because my mind (or soul) willed them to. I’m still working through all the ACBs, but I think I’m on the right track.
I did make a note on this passage that I don’t think directly addresses this question, but I thought might be worth sharing here anyway: If something is divisible into parts, those parts can obviously also be treated as a whole. My legs and arms and soul are all parts of me, and I am a part of the universe. Since it’s obviously not my soul moving the whole universe, some other soul must be the ultimate cause of all motion, including my own.
Reply to “Physics VII.1: What is Aristotle's argument that everything that is in movement must be moved by something?”