But this is impiety.

There is, however, a more plausible account of the matter given by others, who make their likes or dislikes the criterion of excellence.
Sometimes nature crosses habit, or conversely, and then they say that such and such fashions or gestures are pleasant, but they do not like to exhibit them before men of sense, although they enjoy them in private.
'Very true.' And do vicious measures and strains do any harm, or good measures any good to the lovers of them?
'Probably.' Say, rather 'Certainly': for the gentle indulgence which we often show to vicious men inevitably makes us become like them.

And what can be worse than this?
'Nothing.' Then in a well-administered city, the poet will not be allowed to make the songs of the people just as he pleases, or to train his choruses without regard to virtue and vice.

'Certainly not.' And yet he may do this anywhere except in Egypt; for there ages ago they discovered the great truth which I am now asserting, that the young should be educated in forms and strains of virtue.

These they fixed and consecrated in their temples; and no artist or musician is allowed to deviate from them.