Aristotle's ethics builds upon earlier Greek thought, particularly that of his teacher Plato and Plato's teacher, Socrates. While Socrates left no written works, and Plato wrote dialogues and a few letters, Aristotle wrote treatises in which he sets forth philosophical doctrines directly.
According to Aristotle in his Metaphysics, Socrates was the first Greek philosopher to concentrate on ethics, although he apparently did not give it this name, as a philosophical inquiry concerning how people should best live. Aristotle dealt with this same question but giving it two names, "the political" (or Politics) and "the ethical" (Ethics), with Politics being the more important part. The original Socratic questioning on ethics started at least partly as a response to sophism, which was a popular style of education and speech at the time. Sophism emphasized rhetoric, and argument, and therefore often involved criticism of traditional Greek religion and flirtation with moral relativism.
Aristotle's ethics, or study of character, is built around the premise that people should achieve an excellent character (a virtuous character, "ethikē aretē" in Greek) as a pre-condition for attaining happiness or well-being (eudaimonia). It is sometimes referred to in comparison to later ethical theories as a "character based ethics". Like Plato and Socrates he emphasized the importance of reason for eudaimonia, and that there were logical and natural reasons for humans to behave virtuously, and try to become virtuous.
Aristotle's treatment of the subject is distinct in several ways from that found in Plato's Socratic dialogues.
- Aristotle's presentation is obviously different from Plato's because he does not write in dialogues, but in treatises. Apart from this difference, Aristotle explicitly stated that his presentation was different from Plato's because he started from whatever could be agreed upon by well brought-up gentlemen, and not from any attempt to develop a general theory of what makes anything good. He explained that it was necessary not to aim at too much accuracy at the starting point of any discussion to do with controversial matters such as those concerning what is just or what is beautiful. (From this starting point however, he built up to similar theoretical conclusions concerning the importance of intellectual virtue and a contemplative life.)
- Rather than discussing only four "cardinal virtues" of Plato (courage, temperance, justice, and prudence), all three of the ethical works start with courage and temperance as the two typical moral virtues which can be described as a mean, go on to discuss a whole range of minor virtues and vices which can be described as a mean, and only after that touch upon justice and the intellectual virtues. Aristotle places prudence (phronēsis, often translated as practical wisdom) amongst these intellectual virtues. (Nevertheless, like Plato he eventually says that all the highest forms of the moral virtues require each other, and all require intellectual virtue, and in effect that the most eudaimon and most virtuous life is that of a philosopher.)
- Aristotle emphasizes throughout all his analyses of virtues that they aim at what is beautiful (kalos), effectively equating the good, at least for humans, with the beautiful (to kalon).
- Aristotle's analysis of ethics makes use of his metaphysical theory of potentiality and actuality. He defines eudaimonia in terms of this theory as an actuality (energeia); the virtues which allow eudaimonia (and enjoyment of the best and most constant pleasures) are dynamic-but-stable dispositions (hexeis) which are developed through habituation; and this pleasure in turn is another actuality that complements the actuality of euidaimon living.