Obj. 2:  Further, Boethius says (De Consol. iii) that happiness is “a state made perfect by the aggregate of all good things.”  But state does not indicate operation.  Therefore happiness is not an operation.

Obj. 3:  Further, happiness signifies something existing in the happy one:  since it is man’s final perfection.  But the meaning of operation does not imply anything existing in the operator, but rather something proceeding therefrom.  Therefore happiness is not an operation.

Obj. 4:  Further, happiness remains in the happy one.  Now operation does not remain, but passes.  Therefore happiness is not an operation.

Obj. 5:  Further, to one man there is one happiness.  But operations are many.  Therefore happiness is not an operation.

Obj. 6:  Further, happiness is in the happy one uninterruptedly.  But human operation is often interrupted; for instance, by sleep, or some other occupation, or by cessation.  Therefore happiness is not an operation.

On the contrary, The Philosopher says (Ethic. i, 13) that “happiness is an operation according to perfect virtue.”

I answer that, In so far as man’s happiness is something created, existing in him, we must needs say that it is an operation.  For happiness is man’s supreme perfection.  Now each thing is perfect in so far as it is actual; since potentiality without act is imperfect.  Consequently happiness must consist in man’s last act.  But it is evident that operation is the last act of the operator, wherefore the Philosopher calls it “second act” (De Anima ii, 1):  because that which has a form can be potentially operating, just as he who knows is potentially considering.  And hence it is that in other things, too, each one is said to be “for its operation” (De Coel ii, 3).  Therefore man’s happiness must of necessity consist in an operation.

Reply Obj. 1:  Life is taken in two senses.  First for the very being of the living.  And thus happiness is not life:  since it has been shown (Q. 2, A. 5) that the being of a man, no matter in what it may consist, is not that man’s happiness; for of God alone is it true that His Being is His Happiness.  Secondly, life means the operation of the living, by which operation the principle of life is made actual:  thus we speak of active and contemplative life, or of a life of pleasure.  And in this sense eternal life is said to be the last end, as is clear from John 17:3:  “This is eternal life, that they may know Thee, the only true God.”

Reply Obj. 2:  Boethius, in defining happiness, considered happiness in general:  for considered thus it is the perfect common good; and he signified this by saying that happiness is “a state made perfect by the aggregate of all good things,” thus implying that the state of a happy man consists in possessing the perfect good.  But Aristotle expressed the very essence of happiness, showing by what man is established in this state, and that it is by some kind of operation.  And so it is that he proves happiness to be “the perfect good” (Ethic. i, 7).