One of the most compelling arguments against hedonism emerges from Aristotle's analysis of pleasure, but it would be quite wrong to infer from this that Aristotle rejected hedonism outright. On the contrary, he agreed with the hedonists in believing pleasure to be a highly desirable aspect of life. Their mistake did not lie in valuing pleasure, but in a mistaken conception of what pleasure is. They thought of pleasure as an experience of a special kind produced by certain activities, an experience that explains why we value those activities, just as the fact that some activities cause us pain explains why we view them negatively. In other words, the hedonists construed pleasure as a kind of sensation, the positive counterpart to pain.
However, this is a mistake, and it leads us to think that activity is valuable if it is pleasure producing, whereas on Aristotle's account, the relationship is the other way round; an activity is pleasure producing if it is valuable. So, I get pleasure from golf, for example, because I think it a good game to play, and I find it even more satisfying when I manage to play it well. If we apply this analysis to the good life in general, then, the focus of our aspiration should not be pleasure in the sense of entertainment or bodily gratification, but the pursuit of activities whose value is such that engaging in them will give us pleasure and satisfaction. Taken in combination, the outcome of a good and rewarding human life is not hedos but eudaimonia.
Eudaimonia is usually translated 'happiness', but this is not an altogether helpful translation. It comes from the Greek words meaning 'good'