Q.
75, A. 5, ad 4); and for this reason it can be the subject of an
accident. The statement quoted is verified in God, Who is the Pure
Act; in treating of which subject Boethius employs that phrase (De
Trin. i).

Reply Obj. 7: Rational and sensitive, as differences, are not taken
from the powers of sense and reason, but from the sensitive and
rational soul itself. But because substantial forms, which in
themselves are unknown to us, are known by their accidents; nothing
prevents us from sometimes substituting accidents for substantial
differences.
_______________________

SECOND ARTICLE [I, Q. 77, Art. 2]

Whether There Are Several Powers of the Soul?

Objection 1: It would seem that there are not several powers of the
soul. For the intellectual soul approaches nearest to the likeness of
God. But in God there is one simple power: and therefore also in the
intellectual soul.

Obj. 2: Further, the higher a power is, the more unified it is. But
the intellectual soul excels all other forms in power. Therefore
above all others it has one virtue or power.

Obj. 3: Further, to operate belongs to what is in act. But by the
one essence of the soul, man has actual existence in the different
degrees of perfection, as we have seen above (Q. 76, AA. 3, 4).
Therefore by the one power of the soul he performs operations of
various degrees.

_On the contrary,_ The Philosopher places several powers in the soul
(De Anima ii, 2,3).

_I answer that,_ Of necessity we must place several powers in the
soul. To make this evident, we observe that, as the Philosopher says
(De Coelo ii, 12), the lowest order of things cannot acquire perfect
goodness, but they acquire a certain imperfect goodness, by few
movements; and those which belong to a higher order acquire perfect
goodness by many movements; and those yet higher acquire perfect
goodness by few movements; and the highest perfection is found in
those things which acquire perfect goodness without any movement
whatever. Thus he is least of all disposed of health, who can only
acquire imperfect health by means of a few remedies; better disposed
is he who can acquire perfect health by means of many remedies; and
better still, he who can by few remedies; best of all is he who has
perfect health without any remedies. We conclude, therefore, that
things which are below man acquire a certain limited goodness; and
so they have a few determinate operations and powers. But man can
acquire u