Two things, both of them natural, seem likely to have been the causes of the origin of poetry. Representation comes naturally to human beings from childhood, and so does the universal pleasure in representations.
Aristotle's Poetics, 4. (Aristotle, Poetics, tr. A.J.P. Kenny, Oxford: OUP, 2013: 20.)
Let's take a look at the meaning of Mimetic-
"Mimesis is a critical and philosophical term that carries a wide range of meanings, which include imitation, representation, mimicry, imitatio, receptivity, nonsensuous similarity, the act of resembling, the act of expression, and the presentation of the self." -https://en.wikipedia.org/wiki/Mimesis
When we are children, we often learn from observing others and imitating their actions, which is why it's so funny to see a toddler wearing their parent's shoes or sunglasses. Through these imitations and people's reactions to them, we develop an understanding of things which we draw upon throughout our lives, some positive and some negative.
Sometimes these experiences have a major impact on our lives, which is what inspires one to write a poem and the appreciation we have to observe and learn from other's perspectives gives reason to read poetry and share our own.
This is a subtle point, and I'm a bit surprised that Aristotle didn't spend more time explaining it. Perhaps it merely seemed obvious to him, or perhaps it was part of a larger dialog in Greek philosophy that hasn't survived the test of time.
At any rate, Aristotle is suggesting that we all naturally engage in mimesis: the imitative representation of things we perceive in the world around us. Almost from infancy we observe and try to copy what we perceive. We smile when other people smile at us; we imitate the sounds of animals like cats, dogs, and cows; we watch others work and play and copy their movements so we can do it too; we learn language by repeating sounds and associating them with objects and actions... When a parents, teachers, or mentors say "do it this way," they are expecting you to mimic their actions until you have a firm representation in your head of how the action should be performed. That is the nature of learning.
That is one of the foundations of art. A painting isn't just pretty swirls of color, a play isn't just people walking around on stage saying whatever, a song isn't just carefully arranged tones. All of these things gain power and beauty when they trigger our inner representations of the world, bringing up emotions and memories and making new associations. A well-crafted piece of art offers us a representation of the world that is grounded in what we already know but opens us up to what we hadn't considered. It offers us something new to imitate in our heads.
Two things, both of them natural, seem likely to have been the causes of the origin of poetry. Representation comes naturally to human beings from childhood, and so does the universal pleasure in representations. Aristotle, Poetics, IV. 1448b.
It is easy to assume that the ‘two things’ which Aristotle assigns as the ‘causes of the origin of poetry’ (aitiai phusikai) are specified in this passage. Poetry has two roots, one in our inclination to engage in imitation (IV.a5: to mimeisthai) and the other in a natural pleasure we take in representations (IV.a8: to chairein tois mimemasi).
So does this text specify poetry’s dual origin?
No, matters are not so straightforward. Aristotle explains that by means of imitation (1) we learn our first lessons (matheseis) and that (2) in seeing imitations even of things which are unpleasant we take pleasure because by means of these imitations we are ‘enabled to understand and work out what each item is’ (manthanein kai sullogizesthai).
Now (1) and (2) reduce to a single factor, taking pleasure through imitation in the acquisition of knowledge. Imitation – mimesis – yields elementary knowledge which doesn’t disclose the essence or eide of a thing but only its concrete or phenomenal properties. So what is the real second cause - aitia - of poetry? It is indicated, not in the passage above about representation, but clearly just down the page at 1448b20-21:
‘Representation, then, comes naturally to us, as do melody and rhythm (kata phusin de ontos hemin tou mimeisthai kai tes harmonias kai tou rhuthmou).
An instinct for melody and rhythm is then the second aitia of poetry.
References Aristotle, Poetics, tr. A. Kenny, ISBN 10: 0199608369 / ISBN 13: 9780199608362 Published by Oxford University Press.
R. P. Hardie, ‘The Poetics of Aristotle’, Mind , Jul., 1895, New Series, Vol. 4, No. 15 (Jul., 1895), pp. 350-364: 354-355.
Jonathan Lear, 'Katharisis', Phronesis, Vol. 33, No. 3 (1988), pp. 297-326: 307f.
