We speak of "privation" (1) if something has not one of the
attributes which a thing might naturally have, even if this thing
itself would not naturally have it; e.g. a plant is said to be
"deprived" of eyes.-(2) If, though either the thing itself or its
genus would naturally have an attribute, it has it not; e.g. a blind
man and a mole are in different senses "deprived" of sight; the latter
in contrast with its genus, the former in contrast with his own normal
nature.-(3) If, though it would naturally have the attribute, and when
it would naturally have it, it has it not; for blindness is a
privation, but one is not "blind" at any and every age, but only if
one has not sight at the age at which one would naturally have it.
Similarly a thing is called blind if it has not sight in the medium in
which, and in respect of the organ in respect of which, and with
reference to the object with reference to which, and in the
circumstances in which, it would naturally have it.-(4) The violent
taking away of anything is called privation.

    Indeed there are just as many kinds of privations as there are
of words with negative prefixes; for a thing is called unequal because
it has not equality though it would naturally have it, and invisible
either because it has no colour at all or because it has a poor
colour, and apodous either because it has no feet at all or because it
has imperfect feet. Again, a privative term may be used because the
thing has little of the attribute (and this means having it in a sense
imperfectly), e.g. "kernel-less"; or because it has it not easily or
not well (e.g. we call a thing uncuttable not only if it cannot be cut
but also if it cannot be cut easily or well); or 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. This is why not every man
is "good" or "bad", "just" or "unjust", but there is also an
intermediate state.