scible faculty. For since different powers
have different objects, as stated in the First Part (Q. 77, A. 3),
the passions of different powers must of necessity be referred to
different objects. Much more, therefore, do the passions of different
faculties differ in species; since a greater difference in the object
is required to diversify the species of the powers, than to diversify
the species of passions or actions. For just as in the physical
order, diversity of genus arises from diversity in the potentiality
of matter, while diversity of species arises from diversity of form
in the same matter; so in the acts of the soul, those that belong to
different powers, differ not only in species but also in genus, while
acts and passions regarding different specific objects, included
under the one common object of a single power, differ as the species
of that genus.

In order, therefore, to discern which passions are in the irascible,
and which in the concupiscible, we must take the object of each of
these powers. For we have stated in the First Part (Q. 81, A. 2),
that the object of the concupiscible power is sensible good or evil,
simply apprehended as such, which causes pleasure or pain. But, since
the soul must, of necessity, experience difficulty or struggle at
times, in acquiring some such good, or in avoiding some such evil, in
so far as such good or evil is more than our animal nature can easily
acquire or avoid; therefore this very good or evil, inasmuch as it is
of an arduous or difficult nature, is the object of the irascible
faculty. Therefore whatever passions regard good or evil absolutely,
belong to the concupiscible power; for instance, joy, sorrow, love,
hatred, and such like: whereas those passions which regard good or
bad as arduous, through being difficult to obtain or avoid, belong to
the irascible faculty; such are daring, fear, hope and the like.

Reply Obj. 1: As stated in the First Part (Q. 81, A. 2), the
irascible faculty is bestowed on animals, in order to remove the
obstacles that hinder the concupiscible power from tending towards
its object, either by making some good difficult to obtain, or by
making some evil hard to avoid. The result is that all the irascible
passions terminate in the concupiscible passions: and thus it is that
even the passions which are in the irascible faculty are followed by
joy and sadness which are in the concupiscible faculty.

Reply Obj. 2: Jerome ascribes hatred o