Cursus Philosophicus Thomisticus, Secunda Pars Artis Logicae

TEXT AFTER THE CATEGORIES¹

SUMMARY OF CHAPTER 10.: ON OPPOSITES.

In this chapter Aristotle DOES THREE THINGS: first, he explains the genera of opposition; second, he compares them with one another; third, he explains contraries in particular.

Concerning the first, he sets out four genera of opposition: relative, contrary, privative, and contradictory opposition. He defines relatives as “those things whose very being is said in relation to opposites, or which are said of them in some other way.” He does not define contraries, but explains them by example, such as white and black; and he divides them into immediate contraries, “one of which must necessarily be present in the subject,” such as health and sickness, and mediated contraries, “neither of which must necessarily be present in the subject,” such as white and black. Habit and privation are called privatives; affirmation and negation, contradictories.

In the second part, he proves that these opposites are distinct from one another.

In the third, he gives the properties of contraries: 1) Evil is contrary to good, while both good and evil are contrary to evil. 2) If one contrary is given, the other is given as well. 3) It is impossible for both contraries to belong to the same thing. 4) Contraries are about the same subject. 5) All contraries are either in the same genus or in contrary genera.

SUMMARY OF CHAPTER 11.: ON PRIORITY.

He recounts five modes of priority. First is being prior in time. Second is priority according to the consequence of subsistence: for example, “It is an animal, therefore it is a horse” does not follow, but the converse does; thus animal is prior to horse. Third is priority in order, as the premises are prior in order to the conclusion. Fourth is priority by authority, as a prince is prior to a commoner. Fifth is priority by nature, which is mutually implied with something and yet is its cause, as with the sun and light: the sun is prior by nature to light, although it is simultaneous with it.

SUMMARY OF CHAPTER 12.: ON SIMULTANEITY.

He gives three modes of simultaneity. The first is being simultaneous in time, that is, things whose generation occurs at the same time. The second is simultaneity by convertibility, or by nature, as with correlatives, which are convertible, though neither is the cause of the other. The third is simultaneity in order, or in the division of a genus, as two species under the same genus are simultaneous.

CHAPTER 13.: ON MOTION.

He enumerates six species of motion. The first two are substantial changes, namely generation and corruption. The next two are motions of quantity, namely increase and decrease. The fifth is motion according to quality, namely alteration. The sixth is motion according to place, namely local motion.

CHAPTER 14.: ON HAVING.

He enumerates eight more customary modes of having: 1) Having qualities, such as virtues or vices. 2) Having quantity, such as being three cubits or two cubits in size. 3) Having things that surround us, such as clothes. 4) Having something on a bodily member, such as a ring on a finger. 5) Having the member itself, such as a hand or foot. 6) Having something in a vessel, such as wine or grain. 7) Having by possession, such as a field. 8) Having by cohabitation, such as having a wife.