e 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certain occupations, whereby a man is altogether withdrawn from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.