Aristotle's Poetics V

Comedy is of lower character, not necessarily in a bad sense, but in an 'ugly' or 'misshapen' way. Like a mask, it imitates a face, but in a distorted form. Comedy has a relatively short history, as it was not respected or treated seriously in any manner, certainly not appropriate for a Dithyramb. Comedy progresses Poetry far beyond any spiritual sense and moves along into a sense of self reflection of society, similar to epic poetry. However, Epic Poetry has strict rules when it comes to metre, Comedy on the other hand has no use for these rules. Similar to Epic Poetry, Tragedy follows these rules, and in essence Epic Poems follow after Tragedy, not vice versa.