Why some animals have feet and some do not.
One asks why some animals have feet and some do not. It seems that many that have feet, like flies and bees, were born more to lack them than were fish, which are more perfect animals. must be, potentially, either one. Insofar as the sense of touch itself is neutral, it occupies a kind of "mean" or midway point, and has the power to sense what lies on either side of it. The "excesses" of these qualities, however, destroy or corrupt the sense itself. If a sound is too sharp or too flat, it destroys the hearing; if a "tangible" is too hot or cold, it is painful and will injure the sense of touch. Thus, for the sense to perform properly, a proper mixture and ratio of the sensible qualities is essential. On this point, and for a definition of excellentiae sensibilium, see A.'s De anima 2.4.9. It is in this way, namely, that a sense must occupy the mean between extremes or the excess of sensible qualities, that touch is midway between the excellentiae sensibilium.
One must say that animals with ringed bodies have a weak nature, and this is why what they lack in composition nature provides in organization, providing them with many feet by which a ringed body can be supported. But fish stay in the water, which is not a solid body, and this is why water cannot support any sort of a weighty body walking on it. And this is why no fish has feet, except for one that lives equally in the water and on land or which has naturally to seek its nutriment on the bottom of the water. Thus, because nature operates for the sake of an end, and "does nothing in vain and is not lacking in things necessary," many questions that address these sorts of issues can be solved by reference to nature's intention and its desire.
Why the rational animal has only one species.
Next one asks why the rational animal has only one species, although there are many species of irrational animals. Because as many ways as an individual of a set of opposites is divided, so too for the rest. Therefore, etc.
One must reply that the intellect does not use a bodily organ and this is why it cannot be diversified substantially according to the diversity of the one receiving it. But sense uses a bodily organ, and diversity in matter requires diversity in form. And this is why to the extent that the body, which is the organ for the sensitive soul, is variously proportioned, so too is the sensitive soul diversified. But this diversification of the body is due to the diversity of the soul in a formal sense. And this is why there can be many species of irrational animal, on account of the diversity of the sensitive soul. And again, although there can be many ordered to one end, the end is nevertheless indivisible. But all inferior animals are ordered to "rational animal," and this is why although there are many brute, irrational beasts there will be nevertheless one species of rational animal.
Whether physiognomy can be established on the basis of parts of the body.
"And it is necessary that we recall, etc." In this part the Philosopher makes a determination about anatomy and physiognomy.
One asks whether it is possible to obtain a physiognomy concerning moral traits from the parts of the body.
1. It seems not. For according to the Philosopher in the third book of On the Soul, the intellect does not use a corporeal organ. Therefore, its operation does not occur through a mediating organ. But mores do not occur without the intellect's operation; otherwise, these would be found in brute beasts; therefore, mores cannot be known from body parts.
2. Likewise, this does not follow. According to the Philosopher in the Topics, this or that person is naturally chaste and is therefore chaste. But this conclusion would hold if mores could be known through the disposition of the body; therefore, etc.
3. Likewise, according to the Philosopher in the second book of the Ethics, nature does not accustom itself to contraries; but mores can be made accustomed to contraries. Therefore, mores do not follow the dispositions of nature or matter.
In this chapter, the Philosopher implies the opposite.
One must reply that two things are necessary for mores, that is, virtues, namely, the sensitive appetite and right reason; but the sensitive appetite uses a corporeal organ, and for this reason a corporeal organ is necessarily required for mores. This is why the Philosopher determines in the Ethics that moral virtues exist in the rational appetite through participation, that is, in the sensitive appetite. But right reason is required for the completion of virtue. For if the appetite were not regulated by reason, an error would occur in mores. But now it is the case that some are naturally disposed to fortitude and some to liberality and some to chastity, who nevertheless can be changed or inclined to the opposite by habitual action. And similarly certain ones are naturally disposed to vice, as melancholiacs are to envy and cholerics to wrath, who yet can be habituated to the contraries by the discernment of the intellect. As a result, natural aptitudes to mores or their opposites can be recognized from the parts of the body, with respect to humans. But a habit [ habitus] existing in the soul cannot be recognized from them. For the Philosopher relates that the disciples of Hippocrates showed an excellently portrayed likeness of the man to the best physiognomer, Philotinus, and asked him the natural mores of the one whose image it was, and after inspecting the image he said that it was an image of one who is unstable and incontinent. And the disciples were amazed and rejected what he had said of such a great man, and reported to Hippocrates what he had said, and he responded that the physiognomer had spoken the truth. But he said himself that by means of the discernment of the intellect and the love of study and the natural mores of virtue, he had changed into the contrary. Thus he was by nature one thing, although he was good by operation.
Thus, briefly: One can know by the parts of the body to which mores a man is naturally disposed, although one cannot know what mores he will exercise and use.
1. On to the arguments. To the first, one must reply that although the intellect does not use an organ, nevertheless it requires sensitive organs for its operation, and this is why the intellect's operation is often changed by the various dispositions of the body. For it is impeded in madmen owing to an injury to the organ of phantasy and so the body's dispositions contribute a great deal to mores.
2. To the second, one must reply that someone who is chaste is properly one who has the habit of chastity and not one who has the potential or aptitude for it. And it therefore does not follow: "He is naturally chaste, and therefore he is chaste."
3. To the third, one must reply that mores do not follow upon the dispositions of the body by necessity; but that there rather is a certain inclination toward mores owing to the diverse disposition of the body.
-  See A., DA 184.108.40.206-30 ( SZ 1: 93-95). Since physiognomers sought to deduce moral traits such as bravery, rectitude, cowardice, or lecherousness from physical traits, mores here can probably be safely translated as "moral traits." For the remainder of this passage, however, the original Latin will be left intact to assist the reader in forming his or her own opinion.
-  Ar., Topica 2.11 (115b14-17); trans. Boethius (PL 64: 934A); A., Topica 2.2.8. "Naturally chaste": it was something of a commonplace that a cold complexion naturally supports chastity. For discussion with reference to the Virgin Mary's chastity, see Ps. Albertus Magnus, Quaestiones super Evangelium, q. 18, 6-8; for the arguments to the contrary, see Quaestiones super Evangelium, q. 18, 9-11. For a discussion of this question, see also Resnick (2002).
-  Various versions of the tale are collected in Foerster, 2:187-91. Compare with DA 220.127.116.11 (SZ1: 93) where the name given is Phylemon.