Kitap 9
19
Imperishable things are resembled in this respect by things which are always undergoing transformation, such as earth and fire; for the latter too are always active, since they have their motion independently and in themselves.Cf. Aristot. De Gen. et Corr. 337a 1-7. Other potentialities, according to the distinctions already made,Aristot. Met. 9.5.2. all admit of the opposite result; for that which is capable of causing motion in a certain way can also cause it not in that way; that is if it acts rationally.
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The same irrational potentialities can only produce opposite results by their presence or absence.
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Thus if there are any entities or substances such as the dialecticiansFor this description of the Platonists cf. Aristot. Met. 1.6.7. describe the Ideas to be, there must be something which has much more knowledge than absolute knowledge, and much more mobility than motion; for they will be in a truer sense actualities, whereas knowledge and motion will be their potentialities.This is a passing thrust at the Ideal theory. Absolute knowledge (the faculty of knowledge) will be a mere potentiality, and therefore substantially posterior to its actualization in particular instances. Thus it is obvious that actuality is prior both to potentiality and to every principle of change.
1
That a good actuality is both better and more estimable than a good potentiality will be obvious from the following arguments. Everything of which we speak as capable is alike capable of contrary results; e.g., that which we call capable of being well is alike capable of being ill, and has both potentialities at once; for the same potentiality admits of health and disease, or of rest and motion, or of building and of pulling down, or of being built and of falling down.
