In one way we speak of privation when something has nothing of the sort of things given by nature, even if the thing itself does not possess it by nature, as, for instance, we say that plants are deprived of eyes. In another, when the thing itself or the genus to which it belongs does not possess something, though the latter ought to belong to the former naturally, e.g. the way in which a blind man is deprived of sight differs from that in which a mole is deprived of the same attribute; for the latter is deprived of sight in virtue of its genus (for it is in so far as it is a rodent and not as a mole that it is deprived of sight, since rodents do possess sight by nature), while the former in virtue of himself. Again, when something has not an attribute which ought to possess by nature and at the time it ought to possess it; for blindness is a sort of privation, yet an animal is not said to be blind at any and every age, but only if it has not sight at the time at which it ought to by nature (for whelps cannot see). And similarly when something either in respect of the medium (e.g. in the light, not in the dark) or in respect of the organ (e.g. in the eyes, not in the legs) or in respect of the object in relation to which (e.g. the tree, not the voice) or in respect of the way in which it is done (e.g. we cannot see ahead or far away, not behind) has not an attribute, although it ought to possess it by nature. Moreover the violent removal of anything is called privation.
Privations also are said of in the same number of ways as the negations derived from a negative affix; for a thing is called unequal because it has not equality though it could have it, and invisible either because it has no color at all or because it has a dim color, and apodous either because it has no feet at all or because it has inadequate feet. Again, it may mean having something in a small degree, e.g. “kernel-less”; and this means having it in a defective way. Again, because it comes about not easily or not well; e.g. a thing is said “uncuttable” not only because it cannot be cut but also because it cannot be cut easily or well. Again, because it has not the attribute at all; for it is not the one-eyed man but he who is sightless in both eyes that is called blind. Hence not every man is good or bad, just or unjust, but there is also an intermediate state.
Bibliography: Aristotle, Metaphysics (1022b.22 έως 1023a.7)
Translation: George Kotsalis