Thomas Aquinas, Summa Theologiae

Objection 1: It would seem that the intellectual soul is united to the body through the medium of accidental dispositions. For every form exists in its proper disposed matter. But dispositions to a form are accidents. Therefore we must presuppose accidents to be in matter before the substantial form; and therefore before the soul, since the soul is a substantial form.

Objection 2: Further, various forms of one species require various parts of matter. But various parts of matter are unintelligible without division in measurable quantities. Therefore we must suppose dimensions in matter before the substantial forms, which are many belonging to one species.

Objection 3: Further, what is spiritual is connected with what is corporeal by virtual contact. But the virtue of the soul is its power. Therefore it seems that the soul is united to the body by means of a power, which is an accident.

On the contrary, Accident is posterior to substance, both in the order of time and in the order of reason, as the Philosopher says, Metaph. vii (Did. vi, 1). Therefore it is unintelligible that any accidental form exist in matter before the soul, which is the substantial form.

I answer that, If the soul were united to the body, merely as a motor, there would be nothing to prevent the existence of certain dispositions mediating between the soul and the body; on the contrary, they would be necessary, for on the part of the soul would be required the power to move the body; and on the part of the body, a certain aptitude to be moved by the soul.

If, however, the intellectual soul is united to the body as the substantial form, as we have already said above (Article 1), it is impossible for any accidental disposition to come between the body and the soul, or between any substantial form whatever and its matter. The reason is because since matter is in potentiality to all manner of acts in a certain order, what is absolutely first among the acts must be understood as being first in matter. Now the first among all acts is existence. Therefore, it is impossible for matter to be apprehended as hot, or as having quantity, before it is actual. But matter has actual existence by the substantial form, which makes it to exist absolutely, as we have said above (Article 4). Wherefore it is impossible for any accidental dispositions to pre-exist in matter before the substantial form, and consequently before the soul.

Reply to Objection 1: As appears from what has been already said (Article 4), the more perfect form virtually contains whatever belongs to the inferior forms; therefore while remaining one and the same, it perfects matter according to the various degrees of perfection. For the same essential form makes man an actual being, a body, a living being, an animal, and a man. Now it is clear that to every "genus" follow its own proper accidents. Therefore as matter is apprehended as perfected in its existence, before it is understood as corporeal, and so on; so those accidents which belong to existence are understood to exist before corporeity; and thus dispositions are understood in matter before the form, not as regards all its effects, but as regards the subsequent effect.

Reply to Objection 2: Dimensions of quantity are accidents consequent to the corporeity which belongs to the whole matter. Wherefore matter, once understood as corporeal and measurable, can be understood as distinct in its various parts, and as receptive of different forms according to the further degrees of perfection. For although it is essentially the same form which gives matter the various degrees of perfection, as we have said (ad 1), yet it is considered as different when brought under the observation of reason.

Reply to Objection 3: A spiritual substance which is united to a body as its motor only, is united thereto by power or virtue. But the intellectual soul is united by its very being to the body as a form; and yet it guides and moves the body by its power and virtue.

Articulus 6

Argumentum 1

Ad sextum sic proceditur. Videtur quod anima intellectiva uniatur corpori mediantibus aliquibus dispositionibus accidentalibus. Omnis enim forma est in materia sibi propria et disposita. Sed dispositiones ad formam sunt accidentia quaedam. Ergo oportet praeintelligi accidentia aliqua in materia ante formam substantialem, et ita ante animam, cum anima sit quaedam substantialis forma.

Argumentum 2

Praeterea, diversae formae unius speciei requirunt diversas materiae partes. Partes autem materiae diversae non possunt intelligi nisi secundum divisionem dimensivarum quantitatum.

Ergo oportet intelligere dimensiones in materia ante formas substantiales, quae sunt multae unius speciei.

Argumentum 3

Praeterea, spirituale applicatur corporali per contactum virtutis.

Virtus autem animae est eius potentia. Ergo videtur quod anima unitur corpori mediante potentia, quae est quoddam accidens.

Sed Contra

Sed contra est quod accidens est posterius substantia et tempore et ratione, ut dicitur in VII metaphys..

Non ergo forma accidentalis aliqua potest intelligi in materia ante animam, quae est forma substantialis.

Corpus

Respondeo dicendum quod, si anima uniretur corpori solum ut motor, nihil prohiberet, immo magis necessarium esset esse aliquas dispositiones medias inter animam et corpus, potentiam scilicet ex parte animae, per quam moveret corpus; et aliquam habilitatem ex parte corporis, per quam corpus esset ab anima mobile. Sed si anima intellectiva unitur corpori ut forma substantialis, sicut iam supra dictum est, impossibile est quod aliqua dispositio accidentalis cadat media inter corpus et animam, vel inter quamcumque formam substantialem et materiam suam. Et huius ratio est quia, cum materia sit in potentia ad omnes actus ordine quodam, oportet quod id quod est primum simpliciter in actibus, primo in materia intelligatur. Primum autem inter omnes actus est esse.

Impossibile est ergo intelligere materiam prius esse calidam vel quantam, quam esse in actu. Esse autem in actu habet per formam substantialem, quae facit esse simpliciter, ut iam dictum est.

Unde impossibile est quod quaecumque dispositiones accidentales praeexistant in materia ante formam substantialem; et per consequens neque ante animam.

Ad 1

Ad primum ergo dicendum quod, sicut ex praedictis patet, forma perfectior virtute continet quidquid est inferiorum formarum. Et ideo una et eadem existens, perficit materiam secundum diversos perfectionis gradus. Una enim et eadem forma est per essentiam, per quam homo est ens actu, et per quam est corpus, et per quam est vivum, et per quam est animal, et per quam est homo. Manifestum est autem quod unumquodque genus consequuntur propria accidentia. Sicut ergo materia praeintelligitur perfecta secundum esse ante intellectum corporeitatis, et sic de aliis; ita praeintelliguntur accidentia quae sunt propria entis, ante corporeitatem. Et sic praeintelliguntur dispositiones in materia ante formam, non quantum ad omnem eius effectum, sed quantum ad posteriorem.

Ad 2

Ad secundum dicendum quod dimensiones quantitativae sunt accidentia consequentia corporeitatem, quae toti materiae convenit. Unde materia iam intellecta sub corporeitate et dimensionibus, potest intelligi ut distincta in diversas partes, ut sic accipiat diversas formas secundum ulteriores perfectionis gradus. Quamvis enim eadem forma sit secundum essentiam quae diversos perfectionis gradus materiae attribuit, ut dictum est; tamen secundum considerationem rationis differt.

Ad 3

Ad tertium dicendum quod substantia spiritualis quae unitur corpori solum ut motor, unitur ei per potentiam vel virtutem. Sed anima intellectiva corpori unitur ut forma per suum esse.

Administrat tamen ipsum et movet per suam potentiam et virtutem.