The term opposite
is applied to (a) contradiction; (b) contraries; (c) relative terms; (d) privation; (e) state; (f) extremes; e.g. in the process of generation and destruction. And (g) all things which cannot be present at the same time in that which admits of them both are called opposites; either themselves or their constituents. Grey
and white
do not apply at the same time to the same thing, and hence their constituents are opposite.
Contrary
means: (a) attributes, generically different, which cannot apply at the same time to the same thing. (b) The most different attributes in the same genus; or (c) in the same subject; or (d) falling under the same faculty. (e) Things whose difference is greatest absolutely, or in genus, or in species.
Other things are called contrary
either because they possess attributes of this kind, or because they are receptive of them, or because they are productive of or liable to them, or actually produce or incur them, or are rejections or acquisitions or possessions or privations of such attributes.
And since one
and being
have various meanings, all other terms which are used in relation to one
and being
must vary in meaning with them; and so same,
other
and contrary
must so vary, and so must have a separate meaning in accordance with each category.
Things are called other in species
(a) which belong to the same genus and are not subordinate one to the other; or (b) which are in the same genus and contain a differentia; or (c) which contain a contrariety in their essence.
(d) Contraries, too (either all of them or those which are called so in a primary sense), are other in species
than one another; and (e) so are all things of which the formulae are different in the final species of the genus (e.g., man
and horse
are generically indivisible, but their formulae are different); and (f) attributes of the same substance which contain a difference. The same in species
has the opposite meanings to these.