Mimesis in Plato and Aristotle
The central meaning of the ancient Greek word μίμησις‚ (mimesis) is 'imitation', but besides being used in everday contexts with this meaning, the word is also used as a technical term by the philosophers Plato and Aristotle in their discussions of art and literature. Two different ways in which the word is used in these contexts need to be distinguished.
Mimesis and diegesis
In Republic Books II & III, while discussing the place of literature in the education of the Guardians of the Ideal State (376e-400c, especially 392c-398b), Plato contrasts mimesis with diegesis (διήγησις, narration or narrative). He applies the term diegesis to those poems or parts of a poem in which the poet speaks in his own person and reports what has been said or what has happened, and the term mimesis to those poems or parts of a poem in which the poet 'speaks the words of a character in the poem', i.e., uses direct speech, so that a person reciting the poem would seek to impersonate this character. Plato illustrates the distinction with the opening lines of Homer's Iliad, contrasting the lines in which the poet, speaking in his own voice, tells how the old priest Chryses asked the commander of the Greek army, Agamemnon, to release his daughter, Chryseis, and the lines in which the poet gives us the very words Chryses used in his appeal, 'speaking with Chryses' voice and trying his hardest to make us believe that it isn't Homer who is speaking, but the old priest' (393a-b). Plato draws the distinction between mimesis and diegesis because he is concerned that the imitation or impersonation of bad or wicked characters, which could be involved in reciting mimetic poetry, will have a harmful effect on the impressionable minds of children.
Artistic production as mimesis
More commonly the word mimesis does not serve to identify a particular type of poetry but is applied to all artistic productions, whether literary or not. In Republic Book X (595a-608b), in developing his case for banishing poets, artists, and musicians from the Ideal State, Plato says that painters merely create the appearances of physical objects such as beds and tables, and since these objects are in turn reflections of the immaterial Forms, which constitute true reality, painters' creations are 'two steps away from reality' (599a). He immediately generalises the point that pictures are merely copies or 'imitations', assuming that poets and musicians, like painters, 'imitate' (μιμεισθαι, mimeisthai) and referring to them collectively as 'imitators' (μιμηταί, mimetai) (597e).
Perhaps surprisingly, this view of artistic production as mimesis ('imitation') seems to have been widely held in fourth century Greece. Aristotle, who is far from sharing the dismissive attitude to artistic production for which Plato argues in Republic Book X, nonetheless opens his Poetics by taking it for granted that 'epic poetry, tragedy, comedy, dithyrambic poetry, and most flute playing and lyre playing are all forms of mimesis' (1447a13-16; and see also 1460b8-9) - though he immediately acknowledges that there are differences between them: 'they differ from one another in three ways - the media in which they imitate are different in kind; the objects they imitate are different; and they do it in different ways' (1447a16-18).
This view of artistic production as mimesis may be thought to be obviously unsatisfactory for at least two reasons:
1. It is implausible to suppose that all forms of artistic production, in whatever medium, are essentially of the same kind. This objection, however, can be met, at least to some extent, by emphasising that the word mimesis has a broader, more flexible meaning than its usual translation as 'imitation' would imply. The concept of mimesis is the concept of making or doing something which in some way or other resembles something else, and so mimesis includes not only imitation but also representation, suggestion, and expression.
2. Insofar as the characterisation of artistic production as mimesis implies that painters, poets, and musicians are 'mere copyists' (as Plato maintains in Republic Book X), it ignores or denies the creative or imaginative aspects of artistic production. However, Plato and Aristotle resist this implication. Plato recognises in the Phaedrus that poets need inspiration if they are to write good poetry: 'if any man come to the gates of poetry without the madness of the Muses, persuaded that skill alone will make him a great poet, then shall he and his works of sanity with him be brought to nought by the poetry of madness' (Phaedrus 245a). Both Plato and Aristotle understand the importance of 'structure' in an artistic production: Aristotle, e.g., insists that a tragedy should be 'a complete whole ... with a beginning, a middle, and an end' (Poetics 1450b23-27; cf. Plato, Phaedrus 264c and 268d; and see further Classical unities). And Aristotle is clearly aware that painters and poets can represent their subjects not as they actually are, but as they might be, e.g., as better or worse than they are: he reports Sophocles' remark that he (Sophocles) portrayed men as they ought to be, whereas Euripides portrayed them as they actually are (Poetics 1460b33-34).
That artistic productions are a form of mimesis remained the generally held view in the Greco-Roman world until the third century CE when the philosopher Philostratus (c170-c245), one of the members of the intellectual circle patronised by the Roman emperor Septimius Severus (reigned 193-21) and his wife Julia Domna, used the word φαντασία (phantasia, imagination) to characterise artistic activity.