Abstract
My aim is to show how Aristotle's theory of friendship supports his thesis that happiness requires virtuous activity. Ethical behavior is valuable, according to the Nicomachean Ethics, not solely because it uses reason (the immoral can use reason too), but also because it is the expression of a loving attitude towards other persons. By emphasizing this aspect of virtuous activity, I defend Aristotle against the charge that his high estimation for pure intellectual activity commits him to an unethical doctrine. I also argue that his theory of love helps explain why he considers the political life second only to the philosophical life.