Thomas Aquinas, Summa Theologiae

Objection 1: It would seem that the whole soul is not in each part of the body; for the Philosopher says in De causa motus animalium (De mot. animal. x): "It is not necessary for the soul to be in each part of the body; it suffices that it be in some principle of the body causing the other parts to live, for each part has a natural movement of its own."

Objection 2: Further, the soul is in the body of which it is the act. But it is the act of an organic body. Therefore it exists only in an organic body. But each part of the human body is not an organic body. Therefore the whole soul is not in each part.

Objection 3: Further, the Philosopher says (De Anima. ii, 1) that the relation of a part of the soul to a part of the body, such as the sight to the pupil of the eye, is the same as the relation of the soul to the whole body of an animal. If, therefore, the whole soul is in each part of the body, it follows that each part of the body is an animal.

Objection 4: Further, all the powers of the soul are rooted in the essence of the soul. If, therefore, the whole soul be in each part of the body, it follows that all the powers of the soul are in each part of the body; thus the sight will be in the ear, and hearing in the eye, and this is absurd.

Objection 5: Further, if the whole soul is in each part of the body, each part of the body is immediately dependent on the soul. Thus one part would not depend on another; nor would one part be nobler than another; which is clearly untrue. Therefore the soul is not in each part of the body.

On the contrary, Augustine says (De Trin. vi, 6), that "in each body the whole soul is in the whole body, and in each part is entire."

I answer that, As we have said, if the soul were united to the body merely as its motor, we might say that it is not in each part of the body, but only in one part through which it would move the others. But since the soul is united to the body as its form, it must necessarily be in the whole body, and in each part thereof. For it is not an accidental form, but the substantial form of the body. Now the substantial form perfects not only the whole, but each part of the whole. For since a whole consists of parts, a form of the whole which does not give existence to each of the parts of the body, is a form consisting in composition and order, such as the form of a house; and such a form is accidental. But the soul is a substantial form; and therefore it must be the form and the act, not only of the whole, but also of each part. Therefore, on the withdrawal of the soul, as we do not speak of an animal or a man unless equivocally, as we speak of a painted animal or a stone animal; so is it with the hand, the eye, the flesh and bones, as the Philosopher says (De Anima ii, 1). A proof of which is, that on the withdrawal of the soul, no part of the body retains its proper action; although that which retains its species, retains the action of the species. But act is in that which it actuates: wherefore the soul must be in the whole body, and in each part thereof.

That it is entire in each part thereof, may be concluded from this, that since a whole is that which is divided into parts, there are three kinds of totality, corresponding to three kinds of division. There is a whole which is divided into parts of quantity, as a whole line, or a whole body. There is also a whole which is divided into logical and essential parts: as a thing defined is divided into the parts of a definition, and a composite into matter and form. There is, further, a third kind of whole which is potential, divided into virtual parts. The first kind of totality does not apply to forms, except perhaps accidentally; and then only to those forms, which have an indifferent relationship to a quantitative whole and its parts; as whiteness, as far as its essence is concerned, is equally disposed to be in the whole surface and in each part of the surface; and, therefore, the surface being divided, the whiteness is accidentally divided. But a form which requires variety in the parts, such as a soul, and specially the soul of perfect animals, is not equally related to the whole and the parts: hence it is not divided accidentally when the whole is divided. So therefore quantitative totality cannot be attributed to the soul, either essentially or accidentally. But the second kind of totality, which depends on logical and essential perfection, properly and essentially belongs to forms: and likewise the virtual totality, because a form is the principle of operation.

Therefore if it be asked whether the whole whiteness is in the whole surface and in each part thereof, it is necessary to distinguish. If we mean quantitative totality which whiteness has accidentally, then the whole whiteness is not in each part of the surface. The same is to be said of totality of power: since the whiteness which is in the whole surface moves the sight more than the whiteness which is in a small part thereof. But if we mean totality of species and essence, then the whole whiteness is in each part of a surface.

Since, however, the soul has not quantitative totality, neither essentially, nor accidentally, as we have seen; it is enough to say that the whole soul is in each part of the body, by totality of perfection and of essence, but not by totality of power. For it is not in each part of the body, with regard to each of its powers; but with regard to sight, it is in the eye; and with regard to hearing, it is in the ear; and so forth. We must observe, however, that since the soul requires variety of parts, its relation to the whole is not the same as its relation to the parts; for to the whole it is compared primarily and essentially, as to its proper and proportionate perfectible; but to the parts, secondarily, inasmuch as they are ordained to the whole.

Reply to Objection 1: The Philosopher is speaking there of the motive power of the soul.

Reply to Objection 2: The soul is the act of an organic body, as of its primary and proportionate perfectible.

Reply to Objection 3: An animal is that which is composed of a soul and a whole body, which is the soul's primary and proportionate perfectible. Thus the soul is not in a part. Whence it does not follow that a part of an animal is an animal.

Reply to Objection 4: Some of the powers of the soul are in it according as it exceeds the entire capacity of the body, namely the intellect and the will; whence these powers are not said to be in any part of the body. Other powers are common to the soul and body; wherefore each of these powers need not be wherever the soul is, but only in that part of the body, which is adapted to the operation of such a power.

Reply to Objection 5: One part of the body is said to be nobler than another, on account of the various powers, of which the parts of the body are the organs. For that part which is the organ of a nobler power, is a nobler part of the body: as also is that part which serves the same power in a nobler manner.

Articulus 8

Argumentum 1

Ad octavum sic proceditur. Videtur quod anima non sit tota in qualibet parte corporis.

Dicit enim philosophus, in libro de causa motus animalium, non opus est in unaquaque corporis parte esse animam; sed in quodam principio corporis existente, alia vivere; eo quod simul nata sunt facere proprium motum per naturam.

Argumentum 2

Praeterea, anima est in corpore cuius est actus. Sed est actus corporis organici. Ergo non est nisi in corpore organico. Sed non quaelibet pars corporis hominis est corpus organicum. Ergo anima non est in qualibet parte corporis tota.

Argumentum 3

Praeterea, in II de anima dicitur quod sicut se habet pars animae ad partem corporis, ut visus ad pupillam, ita anima tota ad totum corpus animalis.

Si igitur tota anima est in qualibet parte corporis, sequitur quod quaelibet pars corporis sit animal.

Argumentum 4

Praeterea, omnes potentiae animae in ipsa essentia animae fundantur. Si igitur anima tota est in qualibet parte corporis, sequitur quod omnes potentiae animae sint in qualibet corporis parte, et ita visus erit in aure, et auditus in oculo. Quod est inconveniens.

Argumentum 5

Praeterea, si in qualibet parte corporis esset tota anima, quaelibet pars corporis immediate dependeret ab anima. Non ergo una pars dependeret ab alia, nec una pars esset principalior quam alia, quod est manifeste falsum.

Non ergo anima est in qualibet parte corporis tota.

Sed Contra

Sed contra est quod Augustinus dicit, in VI de Trin., quod anima in quocumque corpore et in toto est tota, et in qualibet eius parte tota est.

Corpus

Respondeo dicendum quod, sicut in aliis iam dictum est, si anima uniretur corpori solum ut motor, posset dici quod non esset in qualibet parte corporis, sed in una tantum, per quam alias moveret. Sed quia anima unitur corpori ut forma, necesse est quod sit in toto, et in qualibet parte corporis. Non enim est forma corporis accidentalis, sed substantialis.

Substantialis autem forma non solum est perfectio totius, sed cuiuslibet partis. Cum enim totum consistat ex partibus, forma totius quae non dat esse singulis partibus corporis, est forma quae est compositio et ordo, sicut forma domus, et talis forma est accidentalis. Anima vero est forma substantialis, unde oportet quod sit forma et actus non solum totius, sed cuiuslibet partis.

Et ideo, recedente anima, sicut non dicitur animal et homo nisi aequivoce, quemadmodum et animal pictum vel lapideum; ita est de manu et oculo, aut carne et osse, ut philosophus dicit.

Cuius signum est, quod nulla pars corporis habet proprium opus, anima recedente, cum tamen omne quod retinet speciem, retineat operationem speciei. Actus autem est in eo cuius est actus. Unde oportet animam esse in toto corpore, et in qualibet eius parte.

Et quod tota sit in qualibet parte eius, hinc considerari potest, quia, cum totum sit quod dividitur in partes, secundum triplicem divisionem est triplex totalitas. Est enim quoddam totum quod dividitur in partes quantitativas, sicut tota linea vel totum corpus. Est etiam quoddam totum quod dividitur in partes rationis et essentiae; sicut definitum in partes definitionis, et compositum resolvitur in materiam et formam. Tertium autem totum est potentiale, quod dividitur in partes virtutis. Primus autem totalitatis modus non convenit formis, nisi forte per accidens; et illis solis formis, quae habent indifferentem habitudinem ad totum quantitativum et partes eius. Sicut albedo, quantum est de sui ratione, aequaliter se habet ut sit in tota superficie et in qualibet superficiei parte; et ideo, divisa superficie, dividitur albedo per accidens. Sed forma quae requirit diversitatem in partibus, sicut est anima, et praecipue animalium perfectorum, non aequaliter se habet ad totum et partes, unde non dividitur per accidens per divisionem quantitatis. Sic ergo totalitas quantitativa non potest attribui animae nec per se nec per accidens. Sed totalitas secunda, quae attenditur secundum rationis et essentiae perfectionem, proprie et per se convenit formis.

Similiter autem et totalitas virtutis, quia forma est operationis principium.

Si ergo quaereretur de albedine, utrum esset tota in tota superficie et in qualibet eius parte, distinguere oporteret.

Quia si fiat mentio de totalitate quantitativa, quam habet albedo per accidens, non tota esset in qualibet parte superficiei. Et similiter dicendum est de totalitate virtutis magis enim potest movere visum albedo quae est in tota superficie, quam albedo quae est in aliqua eius particula. Sed si fiat mentio de totalitate speciei et essentiae, tota albedo est in qualibet superficiei parte. Sed quia anima totalitatem quantitativam non habet, nec per se nec per accidens, ut dictum est; sufficit dicere quod anima tota est in qualibet parte corporis secundum totalitatem perfectionis et essentiae; non autem secundum totalitatem virtutis. Quia non secundum quamlibet suam potentiam est in qualibet parte corporis; sed secundum visum in oculo, secundum auditum in aure, et sic de aliis.

Tamen attendendum est quod, quia anima requirit diversitatem in partibus, non eodem modo comparatur ad totum et ad partes, sed ad totum quidem primo et per se, sicut ad proprium et proportionatum perfectibile; ad partes autem per posterius, secundum quod habent ordinem ad totum.

Ad 1

Ad primum ergo dicendum quod philosophus loquitur de potentia motiva animae.

Ad 2

Ad secundum dicendum quod anima est actus corporis organici, sicut primi et proportionati perfectibilis.

Ad 3

Ad tertium dicendum quod animal est quod componitur ex anima et corpore toto, quod est primum et proportionatum eius perfectibile. Sic autem anima non est in parte.

Unde non oportet quod pars animalis sit animal.

Ad 4

Ad quartum dicendum quod potentiarum animae quaedam sunt in ea secundum quod excedit totam corporis capacitatem, scilicet intellectus et voluntas, unde huiusmodi potentiae in nulla parte corporis esse dicuntur. Aliae vero potentiae sunt communes animae et corpori, unde talium potentiarum non oportet quod quaelibet sit in quocumque est anima; sed solum in illa parte corporis quae est proportionata ad talis potentiae operationem.

Ad 5

Ad quintum dicendum quod una pars corporis dicitur esse principalior quam alia, propter potentias diversas quarum sunt organa partes corporis. Quae enim est principalioris potentiae organum, est principalior pars corporis, vel quae etiam eidem potentiae principalius deservit.