Aristotle tells people that an understanding of what man's function would give people a clearer account of about what happiness is. Aristotle's conclusion does not establish anything about any particular excellence. It is a claim which stands quite independently of competing conceptions of what man's excellences are. The biological function of the soul, which is alone appealed in the premises of the Eudemian Ethics (EE) argument, seems much too weak a basis on which to establish a conception of human flourishing. Aristotle, when faced with the demand of Thrasymachus to show that what is morally good is also in the interests of the agent that sidesteps the issue by means of a mere sleight of hand. The accounts of ethical virtue are intended to be corollaries of the master argument, and an interpretation of the master argument which took rational activity to be intellectual activity would make the connection between the argument and the accounts of ethical virtue quite mysterious.