If my analysis of the argument from Philoponus found in Simplicius' paraphrase is correct, then Averroes seems to have managed to pinpoint the real drive behind Philoponus' argumentation. If it is possible at all for the heavens to perish or to come to a halt, then this possibility will necessarily be realized, merely on account of the inevitability of nature itself.20 As beginning follows from end, Philoponus tries to prove Biblical creation to be a natural necessity for the naturalist Aristotelian—in fact, one that not even the theological considerations brought in by the Neoplatonists can alter. Not even belief in a supremely benevolent Demiurge can justify the supposition of a corporeal existent infinite in duration, for physical existents must follow physical laws.
So what can be done, from an Aristotelian point of view? The range of application for the principle of finitude (of powers in bodies) can be limited to its barest minimum. This is precisely what we see Averroes do, in the Metaphysics commentary as elsewhere, right after quoting Philoponus' argument. He does so with some considerable success. First, it may be immediately noted that the infinite power argument we have before us has expanded in its scope of application from being a consideration of the finitude of motion to encompass also finitude of existence. This was a Neoplatonist innovation having its roots in Proclus (c. 410-485) :21 but even if the transformation is of significant inherent interest,22 it is at base an un-Aristotelian one. Averroes is quick to point this out. The concept of potency is not to be applied indiscriminately, but with a respect to the subject matter at hand.
Potency is spoken of in several senses: of these there is the potency that is in substance, and that which is in transformation, and that which is in space. And it has been shown that the body of the heavens does not have these potencies, except potency in place only (Tafsir 3:1629.2-4, Bouyges).
Aristotelian matter is everywhere the substrate for change between opposites: so also between potentiality and actuality, and between existence and non-existence. A basic tenet of Aristotelian cosmology, meanwhile, is that the heavenly substrate has no contrary: it is of a separate, ethereal nature, not mixing with the other elements, and this makes the heavenly spheres simple, not complex entities.23 Because the heavens are forever actual both in their existence and in their activity, they have no need of, nor do they even allow for, matter in the sense of hyle phtarthe.24 They do not consequently have potency for destruction (or for that matter for "transformation", ie. for the attainment of contrary qualities or for diminution and growth). Aristotle's infinite power argument in Averroes' estimation has nothing to do with existence and non-existence: a valid judgment both historically and analytically.
So much for limited and unlimited existence. What can be made of Philoponus' argument in the context of celestial motion? As noted before, change is the actualization of a potentiality, either from potency to actuality or from actuality back into a potential state. Change, meanwhile, kinesis in its most general sense, is itself defined as the actuality of a potentiality qua potentiality (Aristotle, Physics 201a27-29, 201b4-5). What this means for an analysis of eternal motion is that such a motion cannot have its actualization at any specific end-point (goal of motion): rather, such a motion is its own end and actuality. The twelfth book of the Metaphysics explains this in terms of celestial motion being desiderative by nature. It is a byproduct of the heavenly intellects' continuous contemplative desire; a happy byproduct, to be sure, since the continuous circular movement of their actual bodies is at the same time the most perfect form of existence and activity any corporeal creature might have.25
Now, although Aristotle's remarks are rather sketchy on this point, the actuality of a change on the basis of Metaphysics 9 results from coinciding active and passive potencies.26 For there to be an eternal motion, both active and passive potencies have to be forever in place. A mover must have and eternally exercise its infinite active capacity for moving and it must have its counterpart in an unceasing passive potency for being moved (in a corporeal object, to wit, the outermost sphere). Here we reach the final frontier for Philoponus' argument. The heavens' primary, in fact their only potency is their capacity for being moved, as we have seen Averroes proclaim. If their continuous circular motion is something constitutive of them, then this heightens the importance of this feature.27 Can it not be said at least that the heavens' passive potency to be moved is finite by definition, by virtue of the fact that they are finite corporeal bodies? Alas, there is no reason to say anything of the kind on the basis of Physics 8. What Aristotle wants to state is only that an infinite active moving force cannot inhere in a body (lest it be released instantaneously, and result in—paradoxically—no motion at all, since all motion takes time). There is no reason why the heavens could not be moved for an infinite time, just so long as this motion is not imparted on them in one infinitely intense move, but rather in a finite continuum.28 Averroes can explain the same idea by distinguishing between power infinite in intensity (which any active infinite potency must be) and power infinite in duration (which any passive potency can be, even such as is housed within a body).29
It seems that on the exegetical front Philoponus' argument fails, if one is willing to accept the many elaborations and distinctions posited by Averroes in defense of the Philosopher's doctrine. However, on the philosophical side Philoponus' inquiries again gain more gravity when we begin to inquire into the nature of such unfailing potencies as are assigned to the heavens in the Metaphysics. Aristotle repeatedly emphasizes that in such eternal activities, there can be absolutely no potentiality.30 Such actualities are accordingly not really actualizations of potencies in the conventional sense at all. Rather, they are some kind of "hyper-actualities", to borrow a label given by R.M.Dancy.31
But if there is in the heavens absolutely no potentiality for perishing, nor even for halting, and if such a potentiality is required for them to be able to perish or even to stop, then does this not mean that they are in both respects absolutely necessary—of their own accord and nature and "without qualification", as the De caelostates? The only remaining dependency in the heavens would be their need for a transcendent mover, and even this requirement would be only of a purely logical nature; in the current scheme, the heaven "requires an eternal mover only in so far as every motion must have a mover", as Averroes is forced to admit in one late work (Questions in Physics 9; 35, Goldstein). The necessitarian implications of temporal Plenitude loom so large here that it is no wonder we find Averroes attempting to back away from such an extreme position even in the Metaphysics commentary. In the present text Averroes claims that "it is possible that motion be necessary by something else and contingent by its essence, the reason being that its existence comes from something else, this being its mover: for if its [the movement's] existence is perpetual, then this must be from the side of the mover" (Tafsir 3:1632.7-9, Bouyges). Quite clearly, Averroes commits to an inconsistency here. Just as clearly, he draws on a distinction not readily available in any naturalistic explanation of modalities, such as the statistical or potency interpretations on which he usually relied.32
Was this article helpful?