And we cannot allow you to pitch your stage in the agora, and make your voices to be heard above ours, or suffer you to address our women and children and the common people on opposite principles to our own.

Come then, ye children of the Lydian Muse, and present yourselves first to the magistrates, and if they decide that your hymns are as good or better than ours, you shall have your chorus; but if not, not.
There remain three kinds of knowledge which should be learnt by freemen--arithmetic, geometry of surfaces and of solids, and thirdly, astronomy.

Few need make an accurate study of such sciences; and of special students we will speak at another time.

But most persons must be content with the study of them which is absolutely necessary, and may be said to be a necessity of that nature against which God himself is unable to contend.

'What are these divine necessities of knowledge ?' Necessities of a knowledge without which neither gods, nor demigods, can govern mankind.