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 hēdonēs, ēthikos" 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".
The dialogue's central question concerns the relative value of pleasure and knowledge, and produces a model for thinking about how complex structures are developed. Socrates begins by summarizing the two sides of the dialogue:
Philebus was saying that enjoyment and pleasure and delight, and the class of feelings akin to them, are a good to every living being, whereas I contend, that not these, but wisdom[5] and intelligence and memory, and their kindred, right opinion and true reasoning, are better and more desirable than pleasure for all who are able to partake of them, and that to all such who are or ever will be they are the most advantageous of all things.
This contest between a life of ease and pleasure and a life of the mind was already a "rich tradition" among earlier Greek philosophers, and was also dealt with in other dialogues of Plato such as the Gorgias and the Republic. But Socrates and his interlocutors go on to dismiss both pleasure and knowledge as unsatisfactory, reasoning that the truly good is a third type, one of a measured and rational mixture of the two. Socrates already hints that this will be the conclusion in the first lines of the dialogue. The discussion however then turns to a complex discussion of which of the two types of life should be awarded second prize. Thought and reason are declared to be winners of this second prize, but in order to reach and explain this conclusion, Socrates expounds a proposed connection between reason and thought and nature, the orderliness of being itself, including the being of happiness and good. Socrates and Protarchos agree that "the body of the universe had a soul, since that body has the same elements as ours, only in every way superior".[8] This argument was also put in the mouth of Socrates by Plato in his Phaedo where Socrates explains that this was a belief he always found lacking in the philosophy of Anaxagoras. Very similar beliefs are reported of Socrates by Plato's less well-known contemporary Xenophon of Athens.