St. Thomas Aquinas (1225-1274)

Summa Theologica

1273

"And (De Anima ii, 3) he [Aristotle] compares the various souls to the species of figures, one of which contains another; as a pentagon contains and exceeds a tetragon."

We must therefore conclude that in man the sensitive soul, the intellectual soul, and the nutritive soul are numerically one soul. This can easily be explained, if we consider the differences of species and forms. For we observe that the species and forms of things differ from one another, as the perfect and imperfect; as in the order of things, the animate are more perfect than the inanimate, and animals more perfect than plants, and man than brute animals; and in each of these genera there are various degrees. For this reason Aristotle, Metaph. viii (Did. vii, 3), compares the species of things to numbers, which differ in species by the addition or subtraction of unity. And (De Anima ii, 3) he compares the various souls to the species of figures, one of which contains another; as a pentagon contains and exceeds a tetragon. Thus the intellectual soul contains virtually whatever belongs to the sensitive soul of brute animals, and to the nutritive souls of plants. Therefore, as a surface which is of a pentagonal shape, is not tetragonal by one shape, and pentagonal by another—-since a tetragonal shape would be superfluous as contained in the pentagonal—-so neither is Socrates a man by one soul, and animal by another; but by one and the same soul he is both animal and man.
(I, Q76 A3)

Uncategorized::Geometry

Reading at Past Masters

St. Thomas Aquinas, Summa Theologiae, trans. Fathers of the English Dominican Province (London: Burns, Oates, and Washburne, 1912-36; New York: Benziger, 1947-48; New York: Christian Classics, 1981). Text from Intelex Past Masters, The Collected Works of St. Thomas Aquinas. Electronic edition. <Link to Past Masters>

06/14/2011