hus we speak of an active or
contemplative life, or of a life of pleasure; and in this way the last
end is called life everlasting, as is clear from the text: "This is
life everlasting, that they know Thee, the only true God."

By the definition of Boethius, that happiness is "a state made perfect
by the aggregate sum of all things good," nothing else is meant than
that the happy man is in a state of perfect good. But Aristotle has
exprest the proper essence of happiness, showing by what it is that
man is constituted in such a state, namely, by a certain activity.

Action is two-fold. There is one variety that proceeds from the agent
to exterior matter, as the action of cutting and burning, and such an
activity can not be happiness, for such activity is not an act and
perfection of the agent, but rather of the patient. There is another
action immanent, or remaining in the agent himself, as feeling,
understanding, and willing. Such action is a perfection and act of the
agent, and an activity of this sort may possibly be happiness.

Since happiness means some manner of final perfection, happiness must
have different meanings according to the different grades of
perfection that there are attainable by different beings capable of
happiness. In God is happiness by essence, because His very being is
His activity, because He does not enjoy any other thing than Himself.
In the angels final perfection is by way of a certain activity,
whereby they are united to the uncreated good; and this activity is in
them one and everlasting. In men, in the state of the present life,
final perfection is by way of an activity whereby they are united to
God. But this activity can not be everlasting or continuous, and by
consequence it is not one, because an act is multiplied by
interruption; and, therefore, in this state of the present life,
perfect happiness is not to be had by man.

Hence the philosopher, placing the happiness of man in this life, says
that it is imperfect, and after much discussion he comes to this
conclusion: "We call them happy, so far as happiness can be
predicated of men." But we have a promise from God of perfect
happiness, when we shall be "like the angels in heaven." As regards
this perfect happiness, the objection drops, because in this state of
happiness the mind of man is united to God by one continuous and
everlasting activity. But in the present life, so far as we fall short
of the unity and continuity of suc