The true aim and virtue of verbal expression in poetry—diction—is to be clear without being low. The clearest poetic expression is that which uses regular words, but this is low, as with the style of Cleophon and of Sthenelus. An impressive diction results from employing strange words: foreign words, metaphors, expanded words, and anything out of the ordinary habits of usage. But to compose entirely based on this impressive diction results only in riddles or barbarisms, riddles if composed only of metaphor, and barbarisms if composed only of foreign words.
Thus, poetic expression must incorporate some mixture of high and low, of common and unusual words. Foreign words, metaphors, and ornamental words will work to prevent the poetry from being low, while the use of common language ensures clarity and accessibility. Extending, shortening, or altering words is also important for the combination of clarity and distinction—by varying the regular form and usual pattern it produces an effect of distinction, and by overlapping with normal usage produces clarity. Those, like Euclides, who ridicule the poet for using this style are wrong in their criticism—though by exaggerating this effect the result can be ridiculous. Moderation is key. For example, Aeschylus and Euripides composed the same iambic line. Euripides changed just one word, substituting a strange word for the regular one, and gave his verse a high style, compared to Aeschylus’s version’s low style.
While all of the previously mentioned techniques are important, a command of metaphor is essential, but cannot be learned from others; instead it is an innate gift based on the ability to perceive likenesses in things. Compound words are best suited to dithyramb, foreign words to epic verse, and metaphors to iambic verse.
Epic is narrative and works in verse, and it is apparent that just as in tragedies, its plots should be dramatic—they should have a single action, be whole and complete, with a beginning, middle, and end, and like a unified creature produce appropriate pleasure, not resembling histories, which produce not single action but a single time and all the events that occurred within that time-span. But many poets do just this, and Homer seems much better than the others because, though the war had a beginning and an even, he did not attempt to treat the entire war, realizing such a narrative would be far too vast. Instead, he chose to focus on one part of the war, using other parts as episodes, while others focus their poems on a single man or a single period or time as with the Cypria or the Little Iliad (the latter is a work sometimes attributed by the ancient Greeks to Homer but which is now, but for thirty lines of text, lost).
Chapters 22-23, Analysis
In this section, Aristotle attempts to explicate a theory of poetic diction, and ideal poetic expression in verse. The main concept here is the idea of balance—a successful poem will mix ordinary language with more complicated, exotic language to achieve a mix of low and high, and a naturalness that would otherwise be missing. Aristotle delineates several types of words that can be incorporated in order to achieve this balance: foreign words, ornamental words, metaphors, and expanded or altered words. An over-emphasis on either type of word results in poetry that is singularly offensive—either pure riddle (in the case of a composition overly laden with metaphors) or pure barbarism (in the case of a composition that makes no attempt to distance itself from common language). Finally, Aristotle emphasizes the importance of metaphor, while noting that the ability to command metaphors is hardly teachable, but instead related to an innate ability to detect similarities between dissimilar things.
In Chapter 23, Aristotle begins to outline his views on epic poetry, defining it as narrative, and in verse. Pointing to Homer as a superior model for epic, he argues that epics should be whole and unified, focusing on a single coherent moment rather than attempting to encompass an entire history and all of the events and character within that history, citing the Cypria and the Little Iliad as examples of works (both now lost) that fail to match Homer’s focus and unity.