Metaphysics

”Prior” and “posterior” are said of some things in one sense because, on the assumption that there is some first thing and beginning in each genus, they are nearer to some determined beginning, either simply and by nature, or relative to something, or somewhere, or by certain people. For example, some things are so in respect of place, because they are nearer either to some place determined by nature (such as the middle or the extreme) or to some chance place, and that which is further is posterior. Others in respect of time (for some are so by being further from the “now”, as in the case of past events, for the Trojan war is prior to the Persian because it is further away from the “now”; and others by being nearer to the “now”, as in the case of future events, for the Nemean games are prior to the Pythian because they are nearer to the “now”, using the “now” as the beginning and first limit). Others in respect of movement (for that which is nearer to the first mover is prior, as a boy is prior to a man; and this too is a certain beginning simply). Others in respect of power (for that which exceeds in power, and is more powerful, is prior; and of this sort is that according whose choice the other, i.e., the posterior, must follow, so that when the former does not move the latter does not move, and when it moves the latter moves; and choice is a beginning). Others in respect of order (and these are all those which, with reference to some one determined thing, stand at a distance according to some formula, as the second man in the rank is prior to the third, and the paranete is prior to the nete; for in the one case the leader of the chorus is the beginning, and in the other the middle string). — In these ways, then, are things said to be prior, but in another way that which is prior in knowledge is also called prior simply. Of these, those which are prior in formula and those in sensation are different. For in formula universals are prior, but in sensation particulars are prior. And in formula also the accident is prior to the whole, as “musical” to “musical man”, for the formula cannot be whole without the part; and yet “musical” cannot exist unless there is someone who is musical. Further, the attributes of prior things are said to be prior, as straightness to smoothness; for the former is an attribute of a line in itself, and the latter of a surface. Some things, then, are called prior and posterior in this way, but others by nature and substance, which are all those that can exist without other things, while the others cannot exist without them; a distinction which Plato used. (And since “to be” is said in many ways, first, the subject is prior, and therefore substance is prior; and secondly, those things which are in capacity and those in actuality are prior in different ways. For some are prior in capacity and others in actuality; e.g. in capacity the half-line is prior to the whole line, and the part to the whole, and the matter to the substance, but in actuality they are posterior; for it is only when the whole has been dissolved that they will exist in actuality.) In a certain way, then, all things that are called prior and posterior are so called according to these. For some can exist without the others in respect of generation (as the whole without the parts), and others in respect of destruction (as the part without the whole). And similarly with the other cases.