Reply Obj. 3:  As stated in Metaph. ix, 7 action is twofold.  One proceeds from the agent into outward matter, such as “to burn” and “to cut.”  And such an operation cannot be happiness:  for such an operation is an action and a perfection, not of the agent, but rather of the patient, as is stated in the same passage.  The other is an action that remains in the agent, such as to feel, to understand, and to will:  and such an action is a perfection and an act of the agent.  And such an operation can be happiness.

Reply Obj. 4:  Since happiness signifies some final perfection; according as various things capable of happiness can attain to various degrees of perfection, so must there be various meanings applied to happiness.  For in God there is happiness essentially; since His very Being is His operation, whereby He enjoys no other than Himself.  In the happy angels, the final perfection is in respect of some operation, by which they are united to the Uncreated Good:  and this operation of theirs is one only and everlasting.  But in men, according to their present state of life, the final perfection is in respect of an operation whereby man is united to God:  but this operation neither can be continual, nor, consequently, is it one only, because operation is multiplied by being discontinued.  And for this reason in the present state of life, perfect happiness cannot be attained by man.  Wherefore the Philosopher, in placing man’s happiness in this life (Ethic. i, 10), says that it is imperfect, and after a long discussion, concludes:  “We call men happy, but only as men.”  But God has promised us perfect happiness, when we shall be “as the angels . . . in heaven” (Matt. 22:30).

Consequently in regard to this perfect happiness, the objection fails:  because in that state of happiness, man’s mind will be united to God by one, continual, everlasting operation.  But in the present life, in as far as we fall short of the unity and continuity of that operation so do we fall short of perfect happiness.  Nevertheless it is a participation of happiness:  and so much the greater, as the operation can be more continuous and more one.  Consequently the active life, which is busy with many things, has less of happiness than the contemplative life, which is busied with one thing, i.e. the contemplation of truth.  And if at any time man is not actually engaged in this operation, yet since he can always easily turn to it, and since he ordains the very cessation, by sleeping or occupying himself otherwise, to the aforesaid occupation, the latter seems, as it were, continuous.  From these remarks the replies to Objections 5 and 6 are evident. ________________________

THIRD ARTICLE [I-II, Q. 3, Art. 3]

Whether Happiness Is an Operation of the Sensitive Part, or of the
Intellective Part Only?

Objection 1:  It would seem that happiness consists in an operation of the senses also.  For there is no more excellent operation in man than that of the senses, except the intellective operation.  But in us the intellective operation depends on the sensitive:  since “we cannot understand without a phantasm” (De Anima iii, 7).  Therefore happiness consists in an operation of the senses also.