I answer that, Happiness consists in an operation of the speculative rather than of the practical intellect. This is evident for three reasons. First because if man's happiness is an operation, it must needs be man's highest operation. Now man's highest operation is that of his highest power in respect of its highest object: and his highest power is the intellect, whose highest object is the Divine Good, which is the object, not of the practical but of the speculative intellect. Consequently happiness consists principally in such an operation, viz. in the contemplation of Divine things. And since that "seems to be each man's self, which is best in him," according to Ethic. ix, 8, and x, 7, therefore such an operation is most proper to man and most delightful to him.
Secondly, it is evident from the fact that contemplation is sought principally for its own sake. But the act of the practical intellect is not sought for its own sake but for the sake of action: and these very actions are ordained to some end. Consequently it is evident that the last end cannot consist in the active life, which pertains to the practical intellect.
Thirdly, it is again evident, from the fact that in the contemplative life man has something in common with things above him, viz. with God and the angels, to whom he is made like by happiness. But in things pertaining to the active life, other animals also have something in common with man, although imperfectly.
Therefore the last and perfect happiness, which we await in the life to come, consists entirely in contemplation. But imperfect happiness, such as can be had here, consists first and principally, in an operation of the practical intellect directing human actions and passions, as stated in Ethic. x, 7,8.
