This is evidently the case in regard to sensible ends.  For if the acquisition of money were through an act of the will, the covetous man would have it from the very moment that he wished for it.  But at the moment it is far from him; and he attains it, by grasping it in his hand, or in some like manner; and then he delights in the money got.  And so it is with an intelligible end.  For at first we desire to attain an intelligible end; we attain it, through its being made present to us by an act of the intellect; and then the delighted will rests in the end when attained.

So, therefore, the essence of happiness consists in an act of the intellect:  but the delight that results from happiness pertains to the will.  In this sense Augustine says (Confess. x, 23) that happiness is “joy in truth,” because, to wit, joy itself is the consummation of happiness.

Reply Obj. 1:  Peace pertains to man’s last end, not as though it were the very essence of happiness; but because it is antecedent and consequent thereto:  antecedent, in so far as all those things are removed which disturb and hinder man in attaining the last end:  consequent inasmuch as when man has attained his last end, he remains at peace, his desire being at rest.

Reply Obj. 2:  The will’s first object is not its act:  just as neither is the first object of the sight, vision, but a visible thing.  Wherefore, from the very fact that happiness belongs to the will, as the will’s first object, it follows that it does not belong to it as its act.

Reply Obj. 3:  The intellect apprehends the end before the will does:  yet motion towards the end begins in the will.  And therefore to the will belongs that which last of all follows the attainment of the end, viz. delight or enjoyment.

Reply Obj. 4:  Love ranks above knowledge in moving, but knowledge precedes love in attaining:  for “naught is loved save what is known,” as Augustine says (De Trin. x, 1).  Consequently we first attain an intelligible end by an act of the intellect; just as we first attain a sensible end by an act of sense.

Reply Obj. 5:  He who has whatever he desires, is happy, because he has what he desires:  and this indeed is by something other than the act of his will.  But to desire nothing amiss is needed for happiness, as a necessary disposition thereto.  And a good will is reckoned among the good things which make a man happy, forasmuch as it is an inclination of the will:  just as a movement is reduced to the genus of its terminus, for instance, “alteration” to the genus “quality.” ________________________

FIFTH ARTICLE [I-II, Q. 3, Art. 5]

Whether Happiness Is an Operation of the Speculative, or of the
Practical Intellect?

Objection 1:  It would seem that happiness is an operation of the practical intellect.  For the end of every creature consists in becoming like God.  But man is like God, by his practical intellect, which is the cause of things understood, rather than by his speculative intellect, which derives its knowledge from things.  Therefore man’s happiness consists in an operation of the practical intellect rather than of the speculative.