Reply Obj. 2: The imperfection of participated Happiness is due to one of two causes. First, on the part of the object of Happiness, which is not seen in Its Essence: and this imperfection destroys the nature of true Happiness. Secondly, the imperfection may be on the part of the participator, who indeed attains the object of Happiness, in itself, namely, God: imperfectly, however, in comparison with the way in which God enjoys Himself. This imperfection does not destroy the true nature of Happiness; because, since Happiness is an operation, as stated above (Q. 3, A. 2), the true nature of Happiness is taken from the object, which specifies the act, and not from the subject.
Reply Obj. 3: Men esteem that there is some kind of happiness to be had in this life, on account of a certain likeness to true Happiness. And thus they do not fail altogether in their estimate. ________________________
FOURTH ARTICLE [I-II, Q. 5, Art. 4]
Whether Happiness Once Had Can Be Lost?
Objection 1: It would seem that Happiness can be lost. For Happiness is a perfection. But every perfection is in the thing perfected according to the mode of the latter. Since then man is, by his nature, changeable, it seems that Happiness is participated by man in a changeable manner. And consequently it seems that man can lose Happiness.
Obj. 2: Further, Happiness consists in an act of the intellect; and the intellect is subject to the will. But the will can be directed to opposites. Therefore it seems that it can desist from the operation whereby man is made happy: and thus man will cease to be happy.
Obj. 3: Further, the end corresponds to the beginning. But man's Happiness has a beginning, since man was not always happy. Therefore it seems that it has an end.
On the contrary, It is written (Matt. 25:46) of the righteous that "they shall go . . . into life everlasting," which, as above stated (A. 2), is the Happiness of the saints. Now what is eternal ceases not. Therefore Happiness cannot be lost.
I answer that, If we speak of imperfect happiness, such as can be had in this life, in this sense it can be lost. This is clear of contemplative happiness, which is lost either by forgetfulness, for instance, when knowledge is lost through sickness; or again by certain occupations, whereby a man is altogether withdrawn from contemplation.
This is also clear of active happiness: since man's will can be changed so as to fall to vice from the virtue, in whose act that happiness principally consists. If, however, the virtue remain unimpaired, outward changes can indeed disturb such like happiness, in so far as they hinder many acts of virtue; but they cannot take it away altogether because there still remains an act of virtue, whereby man bears these trials in a praiseworthy manner. And since the happiness of this life can be lost, a circumstance that appears to be contrary to the nature of happiness, therefore did the Philosopher state (Ethic. i, 10) that some are happy in this life, not simply, but "as men," whose nature is subject to change.