32.1
I answer that, As stated above (Question 31, Article 1), two things are requisite for pleasure: namely, the attainment of the suitable good, and knowledge of this attainment. Now each of these consists in a kind of operation: because actual knowledge is an operation; and the attainment of the suitable good is by means of an operation. Moreover, the proper operation itself is a suitable good. Wherefore every pleasure must needs be the result of some operation.