other, or which being in the same genus have a difference,[1] or which have a contrariety in their substance; and contraries are other than one another in species (either all contraries or those which are so called in the primary sense[2]), and so are those things whose formulae differ in the infima species of the genus (e.g. man and horse are indivisible in genus, but their formulae are different), or which being in the same substance have a difference.[3] 'The same in species' has the various meanings opposite to these.
Chapter 11
The words 'prior' and 'posterior' are applied (1) to some things (on the assumption that there is a first, i.e. a beginning, in each class) because they are nearer some beginning determined either absolutely and by nature, or by reference to something or in some place or by certain people, e.g. things are prior in place because they are nearer either to some place determined by nature, e.g. the middle or the last place, or to some chance object; and that which is further is posterior. — Other things are prior in time; some by being further from the present, i.e. in the case of past events (for the Trojan war is prior to the Persian, because it is further from the present), others by being nearer the present, i.e. in the case of future events (for the Nemean games are prior to the Pythian, if we treat the present as beginning and first point, because they are nearer the present). — Other things are prior in movement; for the things that
- ↑ This definition is wider than the previous one, since it includes species subordinate one to the other.
- ↑ Cf. 1018a 25-31 in distinction from 31-35.
- ↑ No satisfactory explanation of this clause has been proposed. Alexander suggests that Aristotle may mean that individuals with the same specific essence differ in individual essence; but in ordinary language (which alone Aristotle is examining in Δ) these would not be called ἕτερα εἴδει. He also suggests that the reference may be to bodies such as earth and water which are ἕτερα εἴδει without being contrary like fire and water; but these could hardly be said to be ἐν τῇ αὐτῇ οὐσίᾳ. Asclepius suggests more plausibly that the reference may be to different elements in the essence of complex substances, e.g. to heat and cold in the essence of man. Cf. νοῦς and αἴσθησις in the human soul. Aquinas thinks the reference is to attributes in the same substance.
