A convention is an established practice commonly adopted by implicit agreement or precedent. All artistic media employ certain conventions of representation. For example, in watching a play we accept the convention that the stage represents a room, battlefield, or whatever other space the play seeks to portray. Other conventions would include the rules by which we understand a poem to be a sonnet (fourteen lines, iambic pentameter, rhyme scheme etc.), a narrative work of fiction to be a novel, and so on. More generally, literary works make use of a number of conventional uses of language that includes various figurative and rhetorical uses of language, techniques of representation, and cultural understandings about how the world operates.
As Mitchell suggests (p. 13), conventions, or codes, include both a means and a manner. The means are the basic material (language, the physical stage etc.) and manner is different ways these material are used. Mitchell treats conventions as specialized “mini-codes,” but this is a matter of degree rather than of kind, as his defines both code and convention as “social agreements” about ways to represent objects. In the list of examples above, I have more or less begun at the code end of this continuum (the codes of dramatic representation) and proceeded to the convention end of the continuum (conventional uses of language).
We might see literary conventions as the grammar of literature. Just as all speakers of a language share a knowledge of the rules of grammar that enables them to understand each other, so writers and readers of literature share a knowledge of the rules by which we understand literature texts. As with ordinary language, knowledge of the grammar or conventions of literature may be unconscious or conscious, but as with ordinary language we have to learn this grammar. We learn, for example, that when a Shakespeare play calls for a battle scene, the stage represents a field and a handful of actors entire armies, but we may not be fully conscious that we know this convention. The set of conventions by which we recognize a sonnet, by contrast, must be conscious; we are not going to merely intuit that what we are reading is a sonnet. We need not get this knowledge in the classroom; if we read enough sonnets, we’ll begin to recognize the pattern. However, conscious knowledge of literary conventions can help us better understand what kinds of effects the author is trying to produce, especially because many of these effects are achieved by pushing the boundaries of convention. In this respect, literary conventions are much more complex than the grammar of ordinary language. As in ordinary language, we can only make meaning out of a literary statement if we know the conventions it employs. Because we already know the conventions of ordinary language, we can always make a good start on understanding a literary work, but the more familiar we are with the full range of literary conventions the better we will be able to understand, and appreciate, the work.
Because the meanings of conventions, like the meanings of words, are always changing, there is always the potential, some would say the necessity, that we will understand the text differently. Thus Mitchell points out that representations as a “barrier” that cuts across the axis of communication (between author and reader) may be an “obstacle” rather than a “means of communication” (13). This is why some authors and readers, as Mitchell later points out, regard representation as dangerous (pp. 14-15) and others insist that the aim of literary works is not to represent some aspect of reality but to express what is unrepresentable (expressionism) or to reflect on the ways in which we understand the world through language (aestheticism and formalism).