The Republic by Plato Part 4 Page 17

Yes, said Adeimantus; and you may add my suffrage to Damon’s and your own.

Then, I said, our guardians must lay the foundations of their fortress in music?

Yes, he said; the lawlessness of which you speak too easily steals in.

Yes, I replied, in the form of amusement; and at first sight it appears harmless.

Why, yes, he said, and there is no harm; were it not that little by little this spirit of licence, finding a home, imperceptibly penetrates into manners and customs; whence, issuing with greater force, it invades contracts between man and man, and from contracts goes on to laws and constitutions, in utter recklessness, ending at last, Socrates, by an overthrow of all rights, private as well as public.