Read this summary of Plato's Republic. Pay particular attention to the summary of Books 6,7, and 8; the Theory of Universals; to the definition of justice; and to the Ideal City. What are the four types of government which Plato rejects, and why does he reject them?
Concluding a theme brought up most explicitly in the Analogies of the Sun and Divided Line in Book VI, Socrates finally rejects any form of imitative art and concludes that such artists have no place in the just city. He continues on to argue for the immortality of the psyche and even espouses a theory of reincarnation. He finishes by detailing the rewards of being just, both in this life and the next. Artists create things but they are only different copies of the idea of the original. "And whenever any one informs us that he has found a man who knows all the arts, and all things else that anybody knows, and every single thing with a higher degree of accuracy than any other man - whoever tells us this, I think that we can only imagine to be a simple creature who is likely to have been deceived by some wizard or actor whom he met, and whom he thought all-knowing, because he himself was unable to analyze the nature of knowledge and ignorance and imitation".
"And the same object appears straight when looked at out of the water, and crooked when in the water; and the concave becomes convex, owing to the illusion about colours to which the sight is liable. Thus every sort of confusion is revealed within us; and this is that weakness of the human mind on which the art of conjuring and deceiving by light and shadow and other ingenous devices imposes, having an effect upon us like magic".
He speaks about illusions and confusion. Things can look very similar, but be different in reality. Because we are human, at times we cannot tell the difference between the two.
"And does not the same hold also of the ridiculous? There are jests which you would be ashamed to make yourself, and yet on the comic stage, or indeed in private, when you hear them, you are greatly amused by them, and are not at all disgusted at their unseemliness - the case of pity is repeated - there is a principle in human nature which is disposed to raise a laugh, and this which you once restrained by reason, because you were afraid of being thought a buffoon, is now let out again; and having stimulated the risible faculty at the theatre, you are betrayed unconsciously to yourself into playing the comic poet at home".
With all of us, we may approve of something, as long we are not directly involved with it. If we joke about it, we are supporting it.
"Quite true, he said. And the same may be said of lust and anger and all the other affections, of desire and pain and pleasure, which are held to be inseparable from every action - in all of them poetry feeds and waters the passions instead of drying them up; she lets them rule, although they ought to be controlled, if mankind are ever to increase in happiness and virtue".
Sometimes we let our passions rule our actions or way of thinking, although they should be controlled, so that we can increase our happiness.