No. The essence of the soul is not its power. For nothing is in potentiality by reason of an act, as act.
Essentia animae non est eius potentia. Nihil enim est in potentia secundum actum, inquantum est actus.
The act to which primary matter is in potentiality is the substantial form. Therefore the potentiality of matter is nothing else but its essence.
Actus ad quem est in potentia materia prima, est substantialis forma. Et ideo potentia materiae non est aliud quam eius essentia.
Action belongs to the composite, as does existence; for to act belongs to what exists. Now the composite has substantial existence through the substantial form; and it operates by the power which results from the substantial form. Hence an active accidental form is to the substantial form of the agent ... as the power of the soul is to the soul.
Actio est compositi, sicut et esse; existentis enim est agere. Compositum autem per formam substantialem habet esse substantialiter; per virtutem autem quae consequitur formam substantialem, operatur. Unde sic se habet forma accidentalis activa ad formam substantialem agentis ... sicut se habet potentia animae ad animam.
Although the soul is not composed of matter and form, yet it has an admixture of potentiality, as we have said above (Q75, A5, RO4); and for this reason it can be the subject of an accident.
Anima, licet non sit composita ex materia et forma, habet tamen aliquid de potentialitate admixtum ut supra dictum est. Et ideo potest esse subiectum accidentis.
That the accidental form is a principle of action is due to the substantial form. Therefore the substantial form is the first principle of action; but not the proximate principle.
Forma accidentalis est actionis principium, habet a forma substantiali. Et ideo forma substantialis est primum actionis principium, sed non proximum.
Now we observe that what has a soul is not always actual with respect to its vital operations; whence also it is said in the definition of the soul, that it is "the act of a body having life potentially"; which potentiality, however, "does not exclude the soul."
Invenitur autem habens animam non semper esse in actu operum vitae. Unde etiam in definitione animae dicitur quod est "actus corporis potentia vitam habentis," quae tamen potentia "non abiicit animam."
For the soul by its very essence is an act. Therefore if the very essence of the soul were the immediate principle of operation, whatever has a soul would always have actual vital actions, as that which has a soul is always an actually living thing. For as a form the soul is not an act ordained to a further act, but the ultimate term of generation.
Nam anima secundum suam essentiam est actus. Si ergo ipsa essentia animae esset immediatum operationis principium, semper habens animam actu haberet opera vitae; sicut semper habens animam actu est vivum. Non enim, inquantum est forma, est actus ordinatus ad ulteriorem actum, sed est ultimus terminus generationis.
Wherefore, for it to be in potentiality to another act, does not belong to it according to its essence, as a form, but according to its power. So the soul itself, as the subject of its power, is called the first act, with a further relation to the second act.
Unde quod sit in potentia adhuc ad alium actum, hoc non competit ei secundum suam essentiam, inquantum est forma, sed secundum suam potentiam. Et sic ipsa anima, secundum quod subest suae potentiae, dicitur actus primus, ordinatus ad actum secundum.
The operation of the soul is not in the genus of substance; for this belongs to God alone, whose operation is His own substance.
Operatio autem animae non est in genere substantiae; sed in solo Deo, cuius operatio est eius substantia.
Wherefore the Divine power which is the principle of His operation is the Divine Essence itself.
Unde Dei potentia, quae est operationis principium, est ipsa Dei essentia.
This cannot be true either of the soul, or of any creature, as we have said above when speaking of the angels (Q54, A3).
Quod non potest esse verum neque in anima, neque in aliqua creatura; ut supra etiam de Angelo dictum est.
Dionysius (Coel. Hier. xi) says that "heavenly spirits are divided into essence, power, and operation."
Dionysius dicit, XI cap. Caelest. Hier., quod "caelestes spiritus dividuntur in essentiam, virtutem et operationem."
But the potential whole is in each part according to its whole essence, not, however, according to its whole power. Therefore in a way it can be predicated of each part, but not so properly as the universal whole. In this sense, Augustine says that the memory, understanding, and the will are the one essence of the soul.
Totum vero potentiale adest singulis partibus secundum totam suam essentiam, sed non secundum totam virtutem. Et ideo quodammodo potest praedicari de qualibet parte; sed non ita proprie sicut totum universale. Et per hunc modum Augustinus dicit quod memoria, intelligentia et voluntas sunt una animae essentia.
For Augustine says (De Trin. ix, 4), that "mind, knowledge, and love are in the soul substantially, or, which is the same thing, essentially": and (De Trin. x, 11), that "memory, understanding, and will are one life, one mind, one essence."
Dicit enim Augustinus, in IX de Trin., quod "mens, notitia et amor sunt substantialiter in anima, vel, ut idem dicam, essentialiter." Et in X dicit quod "memoria, intelligentia et voluntas sunt una vita, una mens, una essentia."
Therefore the powers of the soul are accidents; and the power of the soul is not its own essence.
Ergo potentiae animae sunt accidentia. Et ita videtur quod potentia animae non sit eius essentia.