On the other hand species
will give us clear proof of
but is of little service for its elimination.
For example, justice is always a virtue, but that
which is not justice may still be a virtue, such as
fortitude, constancy or self-control. Genus
cannot be eliminated by species
unless all the species
included in the genus
be eliminated, as for instance
in the following sentence: That which is neither rational
nor mortal nor an animal is not a man.