The Metaphysics of Theism

Print ISBN 9780199246533, 2001 pp. [81]-[85]

strikes me as particularly likely to be misleading. I think I can most effectively offer my view of it by taking a broad approach based on details already uncovered.

Stage III is the heart of G2, and G2 is an argument from motion the main line of which might be sketched up through stage III in this way. Things obviously get moved, and everything, Z, that gets moved is moved by something else, Y, that explains Z's motion. If Y itself is a moved mover, then Y's motion in moving Z is explained by X, the mover that moves Y in its moving of Z. So if every mover is a moved mover, this explanatory regress of movers is infinite, and the general fact that things get moved is left unexplained.

But some movers of other things are intrinsically moved. Since being intrinsically moved must be explained in terms of having a part that does the moving and a complementary part that is moved by that intrinsic mover, it doesn't constitute an exception to the OQM principle. Unlike ordinary, extrinsically moved movers, such self-movers could serve as termini of explanations of motion, but only if their own intrinsic movers were themselves immovable.

However, animals are the only self-movers of which we have any experience, and souls, the intrinsic movers of animals, are all movable extrinsically per accidens. Moreover, every animal gets generated and destroyed, and so no motion produced by any animal or animals, or by any self-mover relevantly like them, could explain the infinite explanatory regress or, what in this case is the same thing viewed otherwise, the beginningless generative series of movers.

Any self-mover that could serve as the source of such an explanation, that could count as absolutely first, or what I'm calling a cosmic first self-mover, would have to be sempiternally and continuously operative as an extrinsic mover of other things. And just as any first self-mover's intrinsic mover is immovable, so a cosmic first self-mover's intrinsic mover would have to be immovable, since whatever is movable in any way is, in some respect, to

some degree, dependent on something else's moving it (lines 27-9),

59 Some such claim must be the intended point of the otherwise mysterious clause in lines 30-1, 'every motion other than a first self-mover's motion is caused'. As we've seen, it is one of Aquinas's principles that every motion, without exception, is caused. Furthermore, stage IV of argument G2 is intended to reveal what must be the cause of a cosmic first self-mover's motion. It seems to me that Aquinas might have meant to say that every motion other than a first self-mover's motion is initiated—incipitur, or something like it. But the word in the text is causetur.

end p.81

and thus not a viable basis for the explanation of the beginninglessness of the generative series. So, if the beginningless generative series of movers is to be explained by a cosmic first self-mover, that self-mover must itself be moving other things beginninglessly and continuously, and so it must itself be 'moved by a mover that is not moved, neither per se nor per accidens'ilines 32-3). That is, if X is a cosmic first self-mover, capable of serving as the basis for the explanation of the beginningless generative series of movers, X must be a first self-mover that moves other things beginninglessly and continuously. Since the self-movers we are, and are familiar with, are (a) generable and destructible, and (b) only occasionally first self-movers, of course no ordinary self-mover could fill the bill of cosmic first self-mover.

I've been treating a cosmic first self-mover as a purely hypothetical and pretty unlikely entity, one that must be examined for the sake of completeness but that can be discarded thereafter. Aristotle seems to have thought of such an entity, identified as the outermost celestial sphere, as a

cosmological necessity,

60 See e.g. Metaphysics XII 7, 1072a21-7.

but I think Aquinas takes a more ambivalent position in his final appraisal of G2. The second of the two features of G2 that 'appear to weaken the lines of reasoning we have been considering' is that 'in the demonstrations that have just been presented it is assumed that the first thing moved, a heavenly body, is moved from within. From this it follows that it is animate, which many people do not grant. In reply we have to say that if [that] first mover is not assumed to be moved from within, then it must be moved directly by something immovable [that is extrinsic to it]. That is why even Aristotle introduces this conclusion under a disjunction: that one must either arrive directly at a separated, immovable first mover or [arrive] at a self-mover, from which, in turn, one arrives at a separated, immovable first mover'

61 Cf. Physics VIII 5, 258a5-8; In Phys. VIII: L11.1062.

And so we've returned to the fork in the argument. The plainer, and only really satisfactory, way to go is directly towards a sempiternal, separated, immovable first mover as the ultimate explanation of the beginninglessly, continuously moving Aristotelian universe. Anyone who follows the other way, via consideration of a possible cosmic self-mover, will arrive (a little later) at the same destination, as G2's stage IV is designed to show.

end p.82


© Copyright Oxford University Press, 2006. All Rights Reserved

Stage IV

But God is not a part of any self-mover. And so Aristotle, on the basis of the [sort of] mover that is part of a self-mover, further investigates, in his Metaphysics, another, altogether separate mover, which is God. For since every self-mover is moved through appetite, a mover that is part of a self-mover must move on account of its appetite for some appetible object. That appetible object is superior to that mover as regards moving, for what has appetite is in some respect a moved mover, while what is appetible is an altogether unmoved mover. Therefore, there must be a separated, altogether

immovable first mover, which is God. (13.108)

62 Cf. Metaphysics XII 7, 1072a26-30; In Met. XII: L7.2519-22.

All the movers we encountered in argument G2 before stage IV can and should be considered efficient causes of whatever motion is attributed to them, as I said earlier. It's only in case we take seriously the possibility of a cosmic self-mover (as Aristotle did) that we have to recognize final causation, the other sort of motive force in Aquinas's world, the sort of motive force presupposed by the very notion of a self-mover, the only sort that can move a self-mover when it's behaving as such and not merely being pushed around. Without stage IV, argument G2 points to a cosmic first mover that sempiternally and extrinsically sustains nature's beginningless motions and drives them. Stage IV adds the image of a cosmic first mover toward which are drawn the motions that have their sources within nature's self-movers—cosmic (if any) or merely mundane, like us. As might be expected, final causation is very important in Aquinas's natural theology generally, and, as we'll see, it gets fuller treatment later, when some of the questions raised by its use in stage IV of argument G2 will get answered.

With all its labyrinthine complexities, redundancies, and digressions, G2 is certainly not the more elegant or the stronger of SCG's two arguments from motion. Though it's far from being Aquinas's best, however, I think it clearly is his most intricate argument for God's existence. It has fatal flaws, as we've seen, but it also contains lines of thought that illuminate later developments in his natural theology. And I'm sure I haven't yet seen clearly all there is, bad or good, to see in it.

end p.83


© Copyright Oxford University Press, 2006. All Rights Reserved

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