Aristotle first used the term ethics to name a field of study developed by his predecessors Socrates and Plato which is devoted to the attempt to provide a rational response to the question of how humans should best live.
As Aristotle argues in Book II of the Nicomachean Ethics, the man who possesses character excellence will tend to do the right thing, at the right time, and in the right way.
The highest aims are living well, and eudaimonia – a Greek word often translated as well-being, happiness or "human flourishing".
For example, Aristotle thinks that the man whose appetites are in the correct order takes pleasure in acting moderately.
Aristotle also claims that the right course of action depends upon the details of a particular situation, rather than being generated merely by applying a law.
The Nicomachean Ethics has received the most scholarly attention, and is the most easily available to modern readers in many different translations and editions.
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 treatment of the subject is distinct in several ways from that found in Plato's Socratic dialogues.
(NE II.2)The Aristotelian Ethics all aim to begin with approximate but uncontroversial starting points.
One common objection to Aristotle's function argument is that it uses descriptive or factual premises to derive conclusions about what is good.
Aristotle therefore describes several apparently different kinds of virtuous person as necessarily having all the moral virtues, excellences of character.
But such emotional dispositions may also lie at a mean between two extremes, and these are also to some extent a result of up-bringing and habituation.
Such a failure to act in a way that is consistent with one's own decision is called "akrasia", and may be translated as weakness of will, incontinence, or lack of self-mastery.
In his discussion of particular justice, Aristotle says an educated judge is needed to apply just decisions regarding any particular case.
In the Posterior Analytics and Nicomachean Ethics he identified five intellectual virtues as the five ways the soul arrives at truth by affirmation or denial.
Aristotle's teachings spread through the Mediterranean and the Middle East, where some early Islamic regimes allowed rational philosophical descriptions of the natural world.
Al-Farabi was a major influence in all medieval philosophy and wrote many works which included attempts to reconcile the ethical and political writings of Plato and Aristotle.
Later Avicenna, and later still Averroes, were Islamic philosophers who commented on Aristotle as well as writing their own philosophy in Arabic.
Averroes, a Muslim living in Europe, was particularly influential in turn upon European Christian philosophers, theologians and political thinkers.
Later the medieval church scholasticism in Western Europe insisted on Thomist views and suppressed non-Aristotelian metaphysics.
Aquinas also added new theological virtues to Aristotle's system: faith, hope and charity.
Modern science develops theories about the physical world based on experiments and careful observation—in particular, on the basis of exact measurements of time and distance.
Aristotle's well-known function argument is less commonly accepted today, since he seems to use it in order to develop a claim about human perfection from an observation from what is distinctive about man.
But the exact role of the function argument in Aristotle's ethical theory is itself a matter of dispute.