Founded in Athens by Plato in 385 BCE, the Academy was the center of Greek learning. Aristotle spent twenty years there and owes a great deal of his life's work to this formative influence.


Usually translated as “incontinence,” this term connotes a lack of self-control. A person exhibiting akrasia knows what good behavior consists of but lacks the self-control not to give in to physical pleasures. The concept of akrasia is significant to Aristotle, as he generally agrees with the Socratic claim that no one willingly does evil and that all wrongdoing is a result of ignorance. If the incontinent person acts wrongly in full knowledge of what is good, this poses a dilemma for Socratic ethics, that Book VII of Nicomachean Ethics attempts to answer.


This word translates as "recognition" or "discovery." In tragedy, it describes the moment where the hero, or some other character, passes from ignorance to knowledge. This could be a recognition of a long lost friend or family member, or it could be a sudden recognition of some fact about oneself, as is the case with Oedipus. Anagnorisis often occurs at the climax of a tragedy in tandem with peripeteia.


Usually translated as “virtue,” this important term means something more akin to “excellence.” For the Greeks, arete can be used to refer not only to a person’s moral or intellectual virtues, but to any other kind of excellence, be it the fitness of an athlete or even the sharpness of a knife. Generally speaking, a person, animal, or thing exhibits arete when it is performing its function properly. That the Greeks use the term arete in their discussions of ethics implies a strong sense that humans have a function just as knives do, and that we become good by fulfilling this function.


A self-governing political unit that is sometimes under the power of an overseeing nation, as Athens was in Greece.


Literally "tying," the desis is all the action in a tragedy leading up to the climax. Plot threads are craftily woven together to form a more and more complex mess. At the peripeteia, or turning point, these plot threads begin to unravel in what is called the lusis, or denouement.

Doctrine of the Mean

Aristotle’s doctrine, stated most explicitly in Book II, that virtue is a mean state between the vicious extremes of excess and deficiency. This doctrine is left necessarily vague, as Aristotle thinks that this mean varies from person to person. Essentially, it consists of the observation that it is always possible to have too much or too little of a good thing.


This Greek word, which is the root of our word energy, is generally translated as “activity.” However, it is not necessarily an activity in the sense that we might understand it. For instance, Aristotle describes both happiness and contemplation as activities. In calling happiness an energeia, Aristotle contrasts it with virtue, which he considers to be a hexis, or disposition. That is, the virtues dispose us to behave in the correct manner. Actually behaving according to the virtues, however, is not itself a virtue but rather the energeia of happiness.


We can see that this term is the root of our word ethics. However, it is more accurately translated as “character,” which gives us an important insight to understanding Nicomachean Ethics. Aristotle is not so much concerned with moralizing as he is with determining what constitutes an admirable character.


Normally translated as “happiness,” eudaimonia also carries connotations of success and fulfillment. For the Greeks, happiness is not an inner, emotional state, but the activity, or energeia, of a successful person. The Greeks did not share our sharp distinction between the public and the private, so for them, happiness is a public matter that can be evaluated just as accurately by an observer as by the person being observed.

Four Causes

Aristotle's classification of the kinds of causes that a natural philosopher must investigate: 1) the constituent factor; 2) the form or pattern; 3) the immediate origin; and 4) the end or purpose.

Good Life

For Aristotle, the good life required community participation—otherwise, a man was incomplete. Reason and language are what set man apart from the other animals, and he must exercise them in a public forum to live a fulfilling life.


This word translates almost directly as "error," though it is often rendered more elaborately as "tragic flaw." Tragedy, according to Aristotle, involves the downfall of a hero, and this downfall is effected by some error on the part of the hero. This error need not be an overarching moral failing: it could be a simple matter of not knowing something or forgetting something.


Translated as “disposition,” hexis is the term Aristotle uses to qualify the virtues. According to Aristotle, virtue is not something one actively does. Rather, virtue is a disposition to behave in the right way.


This word was normally used in ancient Greece by doctors to mean "purgation" or by priests to mean "purification." In the context of tragedy, Aristotle uses it to talk about a purgation or purification of emotions. Presumably, this means that katharsis is a release of built up emotional energy, much like a good cry. After katharsis, we reach a more stable and neutral emotional state.


Mimesis is the act of creating in someone's mind, through artistic representation, an idea or ideas that the person will associate with past experience. Roughly translatable as "imitation," mimesis in poetry is the act of telling stories that are set in the real world. The events in the story need not have taken place, but the telling of the story will help the listener or viewer to imagine the events taking place in the real world.


When dealing with tragedy, this word is usually translated as "plot," but unlike "plot," mythos can be applied to all works of art. Not so much a matter of what happens and in what order, mythos deals with how the elements of a tragedy (or a painting, sculpture, etc.) come together to form a coherent and unified whole. The overall message or impression that we come away with is what is conveyed to us by the mythos of a piece.


Literally "untying," the lusis is all the action in a tragedy from the climax onward. All the plot threads that have been woven together in the desis are slowly unraveled until we reach the conclusion of the play.


The rival school to the Academy set up by Plato that Aristotle set up after he returned to Athens in 355 BCE. While the Academy continued to thrive on mostly mathematical courses of study, the Lyceum focused more on biology and natural history. It was at the Lyceum that Aristotle wrote most of his surviving works.


A reversal, either from good to bad or bad to good. Peripeteia often occurs at the climax of a story, often prompted by anagnorisis. Indeed, we might say that the peripeteiais the climax of a story: it is the turning point in the action, where things begin to move toward a conclusion.


Often translated as “prudence,” this term is perhaps better, but more cumbersomely, translated as “practical wisdom.” Phronesis is an important intellectual virtue that allows us to reason properly about practical matters. Phronesis consists in no small part of an appropriate application of the practical syllogism.


The root of our word psychology, psuche is generally translated as “soul,” though it carries none of the spiritual connotations of the Christian use of that word. Psuche is that unobservable property that distinguishes living things from nonliving things. The human psuche consists of three major parts: the nutritive part, which it shares with both plants and animals; the appetitive part, which it shares with only animals; and the rational part, which is distinctively human.


A substance that underlies the real attributes of the material world.

Syllogism/Practical Syllogism

A syllogism is a three-term argument consisting of a major premise stating some universal truth (e.g., “All horses have four legs”), a minor premise stating some particular truth (e.g., “Black Beauty is a horse”), and a conclusion derived from these two premises (e.g., “Therefore, Black Beauty has four legs”). The practical syllogism is a form of practical reasoning in syllogistic form, the conclusion of which is an action. An example might be that the major premise “All intruders will be shot on sight” and the minor premise “I see an intruder over there” leads to the practical conclusion of shooting at the intruder.

Theory of Forms

A core theory of Plato’s philosophy that was ultimately rejected by Aristotle.  According to this theory, the objects of experience are just shadows of a higher world of Forms that lie beyond sensory experience. For example, the various things we see in this world that we call beautiful have beauty because they participate in the Form of Beauty, which is itself immaterial and eternal. In Plato’s view, the purpose of philosophy is to train the intellect to see beyond appearances and to grasp the higher world of Forms.


Telos is an important term can be translated variously as “end,” “goal,” or “purpose.” According to Aristotle, we have a telos as humans, which it is our goal to fulfill. This telos is based on our uniquely human capacity for rational thought. Aristotle’s view of humans having a telos based in our rationality leads directly to his conclusion that contemplation is the highest human good. Teleology is defined as the consideration of natural ends or purposes in explaining phenomena.

Unmoved Mover

The first cause of all motion that is itself unmoved. Aristotle extended this natural science concept to his theology, arguing that the Unmoved Mover was equivalent to God. The being is perfect and eternal but does not take an interest in the world.