Aristotle's Poetics is an analysis of the principles of dramatic writing from the 4th century BC. Despite its age, anyone with a passing appreciation of narrative structure probably knows more about it than they think they do. It is in Poetics, after all, that the concepts of the beginning, middle and end are first articulated. In its few extant pages (about 50 in most editions), Aristotle also discusses reversal of fortune, revelation, surprise and shock, and the principle of dramatic change - terminology familiar from any number of modern creative writing guides.
Aristotle's famous teacher, Plato, believed that literature and art distorted reality. He dreamed of ejecting playwrights from his utopian Republic. Aristotle, on the other hand, viewed drama (specifically tragedy) as a representative form consisting of six elements: plot, character, reasoning, diction, song and spectacle. Together, these work to create an "imitation" of life. Controversially, however, the list turns out to be hierarchical. Two-and-a-half millennia later, writers and critics still argue about whether or not Aristotle was right to place plot above character. Detractors will point to Hollywood movies, which often adhere to a classical narrative "template", and claim that detailed characterisation is sacrificed in favour of action. Others will stand with Henry James, who wrote in his 1884 essay The Art of Fiction, "What is character but the determination of incident? What is incident but the illustration of character?"
I first encountered Aristotle when I was a philosophy graduate, and I was immediately fascinated by his conception of a play as a logically consistent system in which distinct parts act together in harmony. Nothing is wasted or superfluous and everything that happens must be inevitable, or at least very likely. This is exemplified by moments of "astonishment" in drama - an effect that is produced when things happen contrary to our expectation but because of one another. An interesting side-effect of this requirement is that tragedy cannot rely simply on facts. If a play based on real people or events fails to convince us, the writer cannot simply protest "but that's what really happened!" There is a fundamental difference between history and drama. The former is particular and the latter is universal. History tells us what did happen but drama tells us what could happen. Of all the ideas expressed in Poetics, this is the one that still inspires me the most.
Poetics also appeals to the obsessive-compulsive impulse in writers: the desire to create something perfect. It may seem ironic, therefore, that many "canonical" plays (William Shakespeare's The Winter's Tale, Anton Chekhov's Three Sisters, Samuel Beckett's Waiting for Godot) deviate so much from the Aristotelian model. Perhaps this is the inevitable consequence of the tension between our human yearning for order and our equally instinctive resistance to rules or formulae. There is also a third possibility. In many tragic plays, we are left with the feeling that the fallen hero has suffered more than he deserved. Even at the core of such "well-made" drama, then, there is the unsettling suggestion of irrationality.