Aristotle didn't know anything about theatre

Why do playwrights still adhere to the philosopher's over-simplistic view of drama? It's a Greek tragedy
The Bacchae by Euripides
Alan Cummings as Dionysus in The Bacchae by Euripides. Photograph: Murdo Macleod

I have a problem with Aristotle. Not the Aristotle who pondered being, politics, or ethics, but the Aristotle who, in the wake of Greek tragedy, tried to nail what made those great plays so great. His Poetics is a fragment of preserved lecture notes, part of a wider riposte to Plato's attack on the poets (perhaps it should be pinged over to Jeremy Hunt pretty damn quick). But it's less the real-life Greek I'm bothered about; it's what we continue to make of him.

Poetics doesn't occupy a crowded field. Writing about playwriting, as I have just done for my new book The Secret Life of Plays, can be a lonely experience, if you're after wisdom from fellow writers. There are a handful of accounts you can trust, most recently David Edgar's indispensable How Plays Work. But Poetics remains first and foremost. Aristotle begins neutrally enough, pledging to analyse "the art of poetic composition in general and its various species", but with item three on his agenda ("how plots should be constructed if the composition is to be an artistic success"), his task begins to become prescriptive. As he proceeds, Aristotle warms to his role as lay adviser, offering famous observations such as "Tragedy cannot exist without a plot but it can without characters" (really?), or "Among simple plots and actions the episodic is the worst" (possibly, but ...). At one point, he even offers tips about apt subjects for plays that always make the heart sink.

Such advice has proved irresistible to subsequent writers on playwriting. Indeed, if you want a view other than mine on Aristotle, try enthusiastic disciple Michael Tierno's bluntly titled Aristotle's Poetics for Screenwriters: Storytelling Secrets from the Greatest Mind in Western Civilization, which suggests Poetics might do for Hollywood what Sun Tzu's The Art of War does for the Pentagon. What playwright Timberlake Wertenbaker has wonderfully called "Aristotalitarianism" is ubiquitous, from the bossy neo-classicism of Ben Jonson or Dryden or Corneille, with their distaste for the unruly pleasures of Shakespeare, to contemporary avatars in tub-thumbing toolkits such as Robert McKee's Story, which claims: "In the 23 centuries since Aristotle wrote Poetics, the 'secrets' of story have been as public as the library down the street," which rather raises the question as to the necessity of his own mighty book. Wherever plot is deemed to trump all other aspects of playwriting, Aristotle's ghost is hovering nearby.

Yet Poetics' fatal flaw (to borrow an Aristotelian term) is that it's an outsider's view of writing. All too often Aristotle's inventory of conventions is mimicked, as if plays were no more than the sum of their parts, and the author a phrenologist detecting a criminal from the shape of their skull. Generations of playwrights and critics have rummaged through Poetics' checklist of elements hoping to find a readymade framework for their plays or analyses. It's very tempting. Technical terms, especially Greek ones, sound very authoritative: take some dianoia, add in a little sophrosyne, sprinkle over it a smidgeon of anagnorisis, work the whole lot into a lovely peripeteia, and wait for the inevitable katharsis.

If I might add my own hubris to that list, another shortcoming of Aristotle's account of playwriting lies in his focus on Sophocles' Oedipus Tyrannus. It's a very good play, no question, but this poster-boy of formal perfection has too often served as a cudgel to beat into shape all sorts of equally good, but formally eccentric works. How would Aristotle's toolkit of the unities – of place, of time, of action – have served him had he considered the unruly danger of Euripides' The Bacchae or the trilogy of The Oresteia, let alone the madcap playfulness of any play by Aristophanes? But then the fact that it stakes everything on one exemplary text perhaps explains the seductive reductiveness of the Poetics.

Philosophers tend to make dogmatic critics, dismembering plays to illustrate their concepts, paring back the biodiversity of actual plays to create a monoculture of well-behaved exemplars. Nevertheless, however much we might crave papyrus records of Aeschylus taking part in a post-show discussion, or a series of unpublished essays by Euripides entitled "Writing in Tavernas", Aristotle's end-of-term report still too often sets the standard. I'm happy to take my hat off to the great Greek, but we need to thumb our noses at his disciples. Playwriting's too rich and strange for their tidy minds.