There remains for us to examine if a difference of a quality never be a
quality, as that of a being is not a being, nor that of a quantity, a
quantity. Does five differ from three by two? No: five does not differ
from three, it only exceeds it by two. How indeed could five differ
from three by two, when five contains two? Likewise, a movement does
not differ from a movement by a movement. As to virtue and vice, here
is one whole opposed to another whole, and it is thus that the wholes
are distinguished. If a distinction were drawn from the same genus,
that is, from quality, instead of founding itself on another genus; as,
for instance, if one said that such a vice referred to pleasures, some
other to anger, some other to acquisitiveness, and if one were to admit
that such a classification was good; it would evidently result that
there are differences that are not qualities.