Philebus

The Philebus is a Socratic dialogue written in the 4th century BC by Plato. Besides Socrates (the main speaker) the other interlocutors are Philebus and Protarchus. Philebus, who advocates the life of physical pleasure (hedonism), hardly participates, and his position is instead defended by Protarchus, who learnt argumentation from Sophists. Socrates proposes there are higher pleasures (such as those of the mind) as well as lower ones, and asks if the best life isn't one that optimally mixes both.
Manuscripts of the work give it the subtitle "peri h¿don¿s, ¿thikos" ("ethics/moral concerning pleasure") implying that its topic is "concerning pleasure" and it is a work on ethics - that is, the question of what way of life is best. However "there are large parts in the dialogue that deal with dialectics and ontology but have nothing to do with pleasure and ethics, or if so, only indirectly"