Kitap 10
2
This may also be seen from the affinity which exists between the various pleasures and the activities which they perfect. For an activity is augmented by the pleasure that belongs to it; since those who work with pleasure always work with more discernment and with greater accuracy—for instance, students who are fond of geometry become proficient in it, and grasp its various problems better, and similarly lovers of music, architecture or the other arts make progress in their favorite pursuit because they enjoy it. An activity then is augmented by its pleasure; and that which augments a thing must be akin to it. But things that are akin to things of different kinds must themselves differ in kind.
3
A still clearer proof may be drawn from the hindrance that activities receive from the pleasure derived from other activities. For instance, persons fond of the flute cannot give their attention to a philosophical discussion when they overhear someone playing the flute, because they enjoy music more than the activity in which they are engaged; therefore the pleasure afforded by the music of the flute impairs the activity of study.
4
The same thing occurs in other cases when a man tries to do two things at once; the pleasanter activity drives out the other, the more so if it is much more pleasant, until the other activity ceases altogether. Hence, when we enjoy something very much, we can hardly do anything else; and when we find a thing only mildly agreeable, we turn to some other occupation; for instance, people who eat sweets at the theater do so especially when the acting is bad.
