Comments on Alanyzer: Can There Be a Self-Mover? Aquinas on Act and Pote...

Maybe this thread is moribund, but if I'm followin...

2008-11-09T15:28:00.000-08:00

Maybe this thread is moribund, but if I'm following the last few comments, this might be useful.

It's important to distinguish between the transitive and intransitive forms of 'move'. The natural reading of (1) is 'move' is the transitive reading. ('She moved the mug from the table' is transitive 'He moves poorly because of his size' is intransitive.) On this reading, something moving to the left is not a case of motion in the relevant sense whereas someone's being moved to the left _is_ the relevant sense. (Just think about it, (1) would be nonsense if 'moved' was read intransitively.)

Of course, as Kenny noted, there are problems with the argument if we read 'move' in (1) as the transitive form because then we have to avoid equivocating by reading 'move' as its intransitive form in the other premises of Aquinas' argument from motion.

Rhoda, Oh, that's the problem? Great! In this sens...

2008-08-18T15:50:00.000-07:00

Rhoda,

Oh, that's the problem? Great!

In this sense of "self motion" St. Thomas insists that everything living, an not just subsistent forms are self movers. See ST I, Q 18. art. 3.

http://www.newadvent.org/summa/1018.htm#article3

Good to hear from you. I think this is the third t...

2008-08-18T15:44:00.000-07:00

Good to hear from you. I think this is the third time we've gone around on this question. I think we're speaking past each other. Let me focus the question. Consider "Going from left to right":

Aquinas: "That's the eduction from potency to act"

Rhoda: "That's an act".

This means you either

1.) Assume Aquinas is wrong about motion, or

2.) You are arguing that to go from A to B is the same as to be at B.

A Thomist,The problem I have with Aquinas' argumen...

2008-08-18T15:31:00.000-07:00

A Thomist,

The problem I have with Aquinas' argument that the motion of a body depends on motion of its parts (and hence is not properly self-motion) is that it is not at all obvious that there cannot be a simple substance (one that has no proper parts) that is a self-mover. (It is probably better here to speak of 'change' rather than motion.) Cartesian souls, angels, or God, for example, are partless, yet have been thought (not by Aquinas but by others) to be self-movers.

Thanks Jessica and A Thomist, for clearly singling...

2008-08-18T15:22:00.000-07:00

Thanks Jessica and A Thomist, for clearly singling out my second idea as the correct one.

Your joint objection that motion (as Aquinas conceives it) isn't a pointlike 'act' or 'event' but rather more like a continuous 'process' is an interesting one. It is plausible to think that the latter reduces to the former. Processes, that is, seem to be sequences of events. If that's right, then my objection to Aquinas stands, though the requisite level of analysis may need to be much more fine-grained than my example suggests.

Take any continuous process and freeze it at an arbitrary instant, call it T1. At T1, some determinate state, call it S1, is realized. Hence S1 is 'in act' with respect to a property, call it F1, that describes the way it is. But S1 is a dynamic state, the state is about to change, so it is T1 also 'in potency' with respect to becoming a different state, S2, characterized by a different property, F2, at a latter time, T2.

In virtue of the fact that the temporal index changes with the motion, I think premise (3) still comes out false. Even if there is a self-mover, it will never be 'in act' and 'in potency' in the same respect at the same time.

Fair question, Brandon. Active/passive may not be ...

2008-08-18T14:50:00.000-07:00

Fair question, Brandon. Active/passive may not be the right terms for what I had in mind. What I was think of was more like cause/effect. Effects are often, and perhaps always, subsequent to their causes.

I agree with Jessica. You give the right account o...

2008-08-17T16:35:00.000-07:00

I agree with Jessica. You give the right account of potency the second time, but your account of motion is not St. Thomas's or Aristotle's. You see motion (moving to the left) as an immediate transition from potency to act, such that there is no transition or "eduction" from what is simply potential to what is simply actual. But the point of the description that St. Thomas gives of motion as "the eduction from potency to act" is that motion is between potency and act. It is neither act as such nor potency as such but the act of the potential with privation.

Briefly, your division that either potency has act or doesn't (your first and second accounts) leaps over exactly what Aristotle and St. Thomas mean by motion.

St. Thomas is giving only a single argument that Aristotle gives in his Physics, and he does not use the one that Aristotle considers most scientific and demonstrative. Aristotle argues that the motion of a body is caused by its parts, and parts must be composed by another.

Your second account of what potency means is the c...

2008-08-17T13:18:00.000-07:00

Your second account of what potency means is the correct one. Potency as such is potency with the privation of the corresponding act.

Your argument, however, considers "going to the left" (a clear example of a motion) as an act without qualification, whereas St. Thomas explicitly denies that motion is an act without qualification. If you say motion is an act, you're simply denying St. Thomas's definition of motion altogether. But so long as you're assuming that St. Thomas is wrong about motion, your argument begs the question.

I'm a little unclear about your third argument (in...

2008-08-16T18:55:00.000-07:00

I'm a little unclear about your third argument (interpreting it as active/passive). If we then understand self-motion as "acting at T1 so that M's future self is F at T2," what are we taking as the thing that is being acted upon (and thus passive)?