The Republic by Plato Part 3 Page 32

Neither are comic and tragic actors the same; yet all these things are but imitations.

They are so.

And human nature, Adeimantus, appears to have been coined into yet smaller pieces, and to be as incapable of imitating many things well, as of performing well the actions of which the imitations are copies.

Quite true, he replied.

If then we adhere to our original notion and bear in mind that our guardians, setting aside every other business, are to dedicate themselves wholly to the maintenance of freedom in the State, making this their craft, and engaging in no work which does not bear on this end, they ought not to practise or imitate anything else; if they imitate at all, they should imitate from youth upward only those characters which are suitable to their profession —