Thomas Aquinas part.question.article I.115.1 · parts resp. · parma page 439

Respondeo dicendum, quod sensibiliter apparet aliqua corpora esse activa. Sed circa corporum actiones tripliciter aliqui erraverunt. Fuerunt enim aliqui, qui totaliter corporibus actiones subtraxerunt. Et haec est opinio Avicebron in libro Fontis Vitae, ubi per rationes quae tactae sunt, probare nititur, quod nullum corpus agit, sed omnes actiones quae videntur esse corporum, sunt actiones cujusdam virtutis spiritualis quae penetrat per omnia corpora; ita quod ignis, secundum eum, non calefacit, sed virtus spiritualis penetrans per ipsum. Et videtur haec opinio derivata esse ab opinione Platonis. Nam Plato posuit omnes formas quae sunt in materia corporali, esse participatas et determinatas, et contractas ad hanc materiam; formas vero separatas esse absolutas, et quasi universales. Et ideo illas formas separatas dicebat esse causas formarum quae sunt in materia. Secundum hoc ergo quod forma quae est in materia corporali, determinata est ad hanc materiam individuatam per quantitatem, ponebat Avicebron, quod a quantitate, prout est individuationis principium, retinetur et arcetur forma corporalis, ne possit se extendere per actionem in aliam materiam; sed solum forma spiritualis et immaterialis, quae non est coarctata per quantitatem, potest effluere per actionem in aliud. Sed ista ratio non concludit quod forma corporalis non sit agens; sed quod non sit agens universale. Secundum enim quod participatur aliquid, secundum hoc est necessarium quod participetur id quod est proprium ei; sicut quantum participatur de lumine, tantum participatur de ratione visibilis. Agere autem, quod nihil est aliud quam facere aliquid actu, est per se proprium actus, inquantum est actus. Unde et omne agens agit sibi simile Sic ergo ex hoc quod aliquid est forma non determinata per materiam quantitati subjectam, habet quod sit agens indeterminatum et universale; ex hoc vero quod est determinata ad hanc materiam, habet quod sit agens contractum et particulare. Unde si esset forma ignis separata, ut Platonici posuerunt, esset aliquo modo causa omnis ignitionis. Sed haec forma ignis quae est in hac materia corporali, est causa hujus ignitionis, quae est ab hoc corpore in hoc corpus; unde et fit talis actio per contactum duorum corporum. Sed tamen haec opinio Avicebron superexcedit opinionem Platonis. Nam Plato ponebat solum formas substantiales separatas; accidentia vero reducebat ad principia materialia, quae sunt magnum et parvum; quae ponebat esse prima contraria; sicut alii rarum et densum. Et ideo tam Plato, quam Avicenna in aliquo ipsum sequentes, ponebant quod agentia corporalia agunt secundum formas accidentales, disponendo materiam ad formam substantialem; sed ultima perfectio, quae est per inductionem formae substantialis, est a principio immateriali. Et haec est secunda opinio de actione corporum, de qua supra dictum est, qu. 45, art. 8, cum de creatione ageretur. Tertia vero opinio fuit Democriti, qui ponebat actionem esse per effluxionem atomorum a corpore agente et passionem esse per receptionem eorumdem in poris corporis patientis. Quam opinionem improbat Aristoteles (in lib. de Gen., text. 75 et seq.). Sequeretur enim quod corpus non pateretur per totum et quod quantitas corporis agentis diminueretur ex hoc quod agit; quae sunt manifeste falsa. Dicendum est ergo, quod corpus agit secundum quod est in actu, in aliud corpus secundum quod est in potentia.

I answer that it is plain to the senses that some bodies are active. But about the actions of bodies some have erred in three ways. For there were some who took actions away from bodies altogether. This is the opinion of Avicebron in the book Fons vitae, where by the reasons touched on above he tries to prove that no body acts, but that all the actions which seem to be those of bodies are actions of a certain spiritual power which penetrates through all bodies; so that fire, on his view, does not heat, but a spiritual power penetrating through it does. And this opinion seems to be derived from the opinion of Plato. For Plato held that all the forms that are in bodily matter are participated and determined, and contracted to this matter, while the separate forms are absolute and, as it were, universal. And so he said that those separate forms are the causes of the forms in matter. Taking it, then, that the form in bodily matter is determined to this matter individuated by quantity, Avicebron held that the bodily form is held back and confined by quantity, as the principle of individuation, so that it cannot extend itself by action into other matter; only a spiritual and immaterial form, not confined by quantity, can flow out by action into another. But this reasoning does not conclude that the bodily form is not an agent, but that it is not a universal agent. For in the measure that something is participated, in that measure what is proper to it must be participated; as, however much of light is participated, that much is participated of the character of the visible. Now to act, which is nothing other than to make something in act, is proper to act as such, in so far as it is act. Hence too every agent produces its like. So, from being a form not determined by matter subject to quantity, a thing has it that it is an undetermined and universal agent; and from being determined to this matter, it has it that it is a contracted and particular agent. Hence if there were a separate form of fire, as the Platonists held, it would in some way be the cause of all burning. But this form of fire, which is in this bodily matter, is the cause of this burning, which passes from this body into this body; hence such action takes place by the contact of two bodies. And yet this opinion of Avicebron goes beyond Plato's. For Plato held only the substantial forms to be separate, and traced accidents back to material principles, the great and the small, which he held to be the first contraries, as others held the rare and the dense. And so both Plato, and Avicenna following him in some respect, held that bodily agents act by their accidental forms, disposing matter for the substantial form, but that the final perfection, which comes by the bringing in of the substantial form, is from an immaterial principle. And this is the second opinion about the action of bodies, of which we spoke above, q. 45, a. 8, when creation was treated. The third opinion was that of Democritus, who held that action takes place through an outflow of atoms from the acting body, and being acted on through their reception in the pores of the body acted on. Aristotle refutes this opinion (On Generation, texts 75 and following). For it would follow that a body is not acted on through the whole of it, and that the quantity of an acting body would be diminished by its acting; both plainly false. It must be said, then, that a body acts in so far as it is in act, upon another body in so far as that is in potency.

Utrum aliquod corpus sit activum. The article's main target is Avicebron (Ibn Gabirol), Fons vitae, not Avicenna; Avicenna enters in the third paragraph, as holding with Plato that bodies only dispose matter while the substantial form comes 'from an immaterial principle' — the giver of forms. The fire example answers Enn. VI.7.11 directly: Plotinus says fire is made by a soul able to make fire, not by rubbing; Aquinas says this fire is made by this fire, by contact. 'Every agent produces its like' (omne agens agit sibi simile) is the axiom Proclus states as El. 28. 'The great and the small' is Plato's material principle as Aristotle reports it (Met. I.6).

Latin transcribed from the Parma plates (vol. 1, p. 439, leaf n478), both columns read with gutter-safe crops.

In the crux Ennead VI.7 [38], How the Multitude of Forms Came to Be, and on the Good, chapter 11