Thomas Aquinas, Summa Theologiae

Objection 1: It would seem that the body of man was not given an apt disposition. For since man is the noblest of animals, his body ought to be the best disposed in what is proper to an animal, that is, in sense and movement. But some animals have sharper senses and quicker movement than man; thus dogs have a keener smell, and birds a swifter flight. Therefore man's body was not aptly disposed.

Objection 2: Further, perfect is what lacks nothing. But the human body lacks more than the body of other animals, for these are provided with covering and natural arms of defense, in which man is lacking. Therefore the human body is very imperfectly disposed.

Objection 3: Further, man is more distant from plants than he is from the brutes. But plants are erect in stature, while brutes are prone in stature. Therefore man should not be of erect stature.

On the contrary, It is written (Eccles. 7:30): "God made man right."

I answer that, All natural things were produced by the Divine art, and so may be called God's works of art. Now every artist intends to give to his work the best disposition; not absolutely the best, but the best as regards the proposed end; and even if this entails some defect, the artist cares not: thus, for instance, when man makes himself a saw for the purpose of cutting, he makes it of iron, which is suitable for the object in view; and he does not prefer to make it of glass, though this be a more beautiful material, because this very beauty would be an obstacle to the end he has in view. Therefore God gave to each natural being the best disposition; not absolutely so, but in the view of its proper end. This is what the Philosopher says (Phys. ii, 7): "And because it is better so, not absolutely, but for each one's substance."

Now the proximate end of the human body is the rational soul and its operations; since matter is for the sake of the form, and instruments are for the action of the agent. I say, therefore, that God fashioned the human body in that disposition which was best, as most suited to such a form and to such operations. If defect exists in the disposition of the human body, it is well to observe that such defect arises as a necessary result of the matter, from the conditions required in the body, in order to make it suitably proportioned to the soul and its operations.

Reply to Objection 1: The sense of touch, which is the foundation of the other senses, is more perfect in man than in any other animal; and for this reason man must have the most equable temperament of all animals. Moreover man excels all other animals in the interior sensitive powers, as is clear from what we have said above (Question 78, Article 4). But by a kind of necessity, man falls short of the other animals in some of the exterior senses; thus of all animals he has the least sense of smell. For man needs the largest brain as compared to the body; both for his greater freedom of action in the interior powers required for the intellectual operations, as we have seen above (Question 84, Article 7); and in order that the low temperature of the brain may modify the heat of the heart, which has to be considerable in man for him to be able to stand erect. So that size of the brain, by reason of its humidity, is an impediment to the smell, which requires dryness. In the same way, we may suggest a reason why some animals have a keener sight, and a more acute hearing than man; namely, on account of a hindrance to his senses arising necessarily from the perfect equability of his temperament. The same reason suffices to explain why some animals are more rapid in movement than man, since this excellence of speed is inconsistent with the equability of the human temperament.

Reply to Objection 2: Horns and claws, which are the weapons of some animals, and toughness of hide and quantity of hair or feathers, which are the clothing of animals, are signs of an abundance of the earthly element; which does not agree with the equability and softness of the human temperament. Therefore such things do not suit the nature of man. Instead of these, he has reason and hands whereby he can make himself arms and clothes, and other necessaries of life, of infinite variety. Wherefore the hand is called by Aristotle (De Anima iii, 8), "the organ of organs." Moreover this was more becoming to the rational nature, which is capable of conceiving an infinite number of things, so as to make for itself an infinite number of instruments.

Reply to Objection 3: An upright stature was becoming to man for four reasons. First, because the senses are given to man, not only for the purpose of procuring the necessaries of life, which they are bestowed on other animals, but also for the purpose of knowledge. Hence, whereas the other animals take delight in the objects of the senses only as ordered to food and sex, man alone takes pleasure in the beauty of sensible objects for its own sake. Therefore, as the senses are situated chiefly in the face, other animals have the face turned to the ground, as it were for the purpose of seeking food and procuring a livelihood; whereas man has his face erect, in order that by the senses, and chiefly by sight, which is more subtle and penetrates further into the differences of things, he may freely survey the sensible objects around him, both heavenly and earthly, so as to gather intelligible truth from all things. Secondly, for the greater freedom of the acts of the interior powers; the brain, wherein these actions are, in a way, performed, not being low down, but lifted up above other parts of the body. Thirdly, because if man's stature were prone to the ground he would need to use his hands as fore-feet; and thus their utility for other purposes would cease. Fourthly, because if man's stature were prone to the ground, and he used his hands as fore-feet, he would be obliged to take hold of his food with his mouth. Thus he would have a protruding mouth, with thick and hard lips, and also a hard tongue, so as to keep it from being hurt by exterior things; as we see in other animals. Moreover, such an attitude would quite hinder speech, which is reason's proper operation.

Nevertheless, though of erect stature, man is far above plants. For man's superior part, his head, is turned towards the superior part of the world, and his inferior part is turned towards the inferior world; and therefore he is perfectly disposed as to the general situation of his body. Plants have the superior part turned towards the lower world, since their roots correspond to the mouth; and their inferior part towards the upper world. But brute animals have a middle disposition, for the superior part of the animal is that by which it takes food, and the inferior part that by which it rids itself of the surplus.

Articulus 3

Argumentum 1

Ad tertium sic proceditur. Videtur quod corpus hominis non habuerit convenientem dispositionem. Cum enim homo sit nobilissimum animalium, corpus hominis debuit esse dispositum optime ad ea quae sunt propria animalis, scilicet ad sensum et motum. Sed quaedam animalia inveniuntur acutioris sensus quam homo, et velocioris motus; sicut canes melius odorant, et aves velocius moventur.

Ergo corpus hominis non est convenienter dispositum.

Argumentum 2

Praeterea, perfectum est cui nihil deest. Sed plura desunt humano corpori quam corporibus aliorum animalium, quae habent tegumenta et arma naturalia ad sui protectionem, quae homini desunt. Ergo corpus humanum est imperfectissime dispositum.

Argumentum 3

Praeterea, homo plus distat a plantis quam ab animalibus brutis.

Sed plantae habent staturam rectam; animalia autem bruta pronam.

Ergo homo non debuit habere staturam rectam.

Sed Contra

Sed contra est quod dicitur Eccle. VII, deus fecit hominem rectum.

Corpus

Respondeo dicendum quod omnes res naturales productae sunt ab arte divina, unde sunt quodammodo artificiata ipsius dei.

Quilibet autem artifex intendit suo operi dispositionem optimam inducere, non simpliciter, sed per comparationem ad finem.

Et si talis dispositio habet secum adiunctum aliquem defectum, artifex non curat. Sicut artifex qui facit serram ad secandum, facit eam ex ferro, ut sit idonea ad secandum; nec curat eam facere ex vitro, quae est pulchrior materia, quia talis pulchritudo esset impedimentum finis. Sic igitur deus unicuique rei naturali dedit optimam dispositionem, non quidem simpliciter, sed secundum ordinem ad proprium finem.

Et hoc est quod philosophus dicit, in II physic., et quia dignius est sic, non tamen simpliciter, sed ad uniuscuiusque substantiam.

Finis autem proximus humani corporis est anima rationalis et operationes ipsius, materia enim est propter formam, et instrumenta propter actiones agentis. Dico ergo quod deus instituit corpus humanum in optima dispositione secundum convenientiam ad talem formam et ad tales operationes. Et si aliquis defectus in dispositione humani corporis esse videtur, considerandum est quod talis defectus sequitur ex necessitate materiae, ad ea quae requiruntur in corpore ut sit debita proportio ipsius ad animam et ad animae operationes.

Ad 1

Ad primum ergo dicendum quod tactus, qui est fundamentum aliorum sensuum, est perfectior in homine quam in aliquo alio animali, et propter hoc oportuit quod homo haberet temperatissimam complexionem inter omnia animalia. Praecedit etiam homo omnia alia animalia, quantum ad vires sensitivas interiores; sicut ex supra dictis apparet.

Ex quadam autem necessitate contingit quod, quantum ad aliquos exteriores sensus, homo ab aliis animalibus deficiat. Sicut homo, inter omnia animalia, habet pessimum olfactum. Necessarium enim fuit quod homo, inter omnia animalia, respectu sui corporis haberet maximum cerebrum, tum ut liberius in eo perficerentur operationes interiorum virium sensitivarum, quae sunt necessariae ad intellectus operationem, ut supra dictum est; tum etiam ut frigiditas cerebri temperaret calorem cordis, quem necesse est in homine abundare, ad hoc quod homo sit rectae staturae. Magnitudo autem cerebri, propter eius humiditatem, est impedimentum olfactus, qui requirit siccitatem.

Et similiter potest assignari ratio quare quaedam animalia sunt acutioris visus et subtilioris auditus quam homo, propter impedimentum horum sensuum quod necesse est consequi in homine ex perfecta complexionis aequalitate. Et eadem etiam ratio est assignanda de hoc quod quaedam animalia sunt homine velociora, cui excellentiae velocitatis repugnat aequalitas humanae complexionis.

Ad 2

Ad secundum dicendum quod cornua et ungulae, quae sunt quorundam animalium arma, et spissitudo corii, et multitudo pilorum aut plumarum, quae sunt tegumenta animalium, attestantur abundantiae terrestris elementi; quae repugnat aequalitati et teneritudini complexionis humanae. Et ideo haec homini non competebant. Sed loco horum habet rationem et manus, quibus potest parare sibi arma et tegumenta et alia vitae necessaria, infinitis modis.

Unde et manus, in III de anima, dicitur organum organorum.

Et hoc etiam magis competebat rationali naturae, quae est infinitarum conceptionum, ut haberet facultatem infinita instrumenta sibi parandi.

Ad 3

Ad tertium dicendum quod habere staturam rectam conveniens fuit homini propter quatuor. Primo quidem, quia sensus sunt dati homini non solum ad vitae necessaria procuranda, sicut aliis animalibus; sed etiam ad cognoscendum. Unde, cum cetera animalia non delectentur in sensibilibus nisi per ordinem ad cibos et venerea, solus homo delectatur in ipsa pulchritudine sensibilium secundum seipsam. Et ideo, quia sensus praecipue vigent in facie, alia animalia habent faciem pronam ad terram, quasi ad cibum quaerendum et providendum sibi de victu, homo vero habet faciem erectam, ut per sensus, et praecipue per visum, qui est subtilior et plures differentias rerum ostendit, libere possit ex omni parte sensibilia cognoscere, et caelestia et terrena, ut ex omnibus intelligibilem colligat veritatem. Secundo, ut interiores vires liberius suas operationes habeant, dum cerebrum, in quo quodammodo perficiuntur, non est depressum, sed super omnes partes corporis elevatum. Tertio, quia oporteret quod, si homo haberet pronam staturam, uteretur manibus loco anteriorum pedum.

Et sic utilitas manuum ad diversa opera perficienda cessaret.

Quarto, quia, si haberet pronam staturam, et uteretur manibus loco anteriorum pedum, oporteret quod cibum caperet ore. Et ita haberet os oblongum, et labia dura et grossa, et linguam etiam duram, ne ab exterioribus laederetur, sicut patet in aliis animalibus. Et talis dispositio omnino impediret locutionem, quae est proprium opus rationis. Et tamen homo staturam rectam habens, maxime distat a plantis. Nam homo habet superius sui, idest caput, versus superius mundi, et inferius sui versus inferius mundi, et ideo est optime dispositus secundum dispositionem totius. Plantae vero habent superius sui versus inferius mundi (nam radices sunt ori proportionales), inferius autem sui versus superius mundi. Animalia vero bruta medio modo, nam superius animalis est pars qua accipit alimentum, inferius autem est pars qua emittit superfluum.