Madness is good.

from Phaedrus by Plato nonfiction ~2 min read

There will be more reason in appealing to the ancient inventors of names, who would never have connected prophecy (mantike) which foretells the future and is the noblest of arts, with madness (manike), or called them both by the same name, if they had deemed madness to be a disgrace or dishonour;-they must have thought that there was an inspired madness which was a noble thing; for the two words, mantike and manike, are really the same, and the letter t is only a modern and tasteless insertion. And this is confirmed by the name which was given by them to the rational investigation of futurity, whether made by the help of birds or of other signs-this, for as much as it is an art which supplies from the reasoning faculty mind (nous) and information (istoria) to human thought (oiesis) they originally termed oionoistike, but the word has been lately altered and made sonorous by the modern introduction of the letter Omega (oionoistike and oionistike), and in proportion prophecy (mantike) is more perfect and august than augury, both in name and fact, in the same proportion, as the ancients testify, is madness superior to a sane mind (sophrosune) for the one is only of human, but the other of divine origin. Again, where plagues and mightiest woes have bred in certain families, owing to some ancient blood-guiltiness, there madness has entered with holy prayers and rites, and by inspired utterances found a way of deliverance for those who are in need; and he who has part in this gift, and is truly possessed and duly out of his mind, is by the use of purifications and mysteries made whole and except from evil, future as well as present, and has a release from the calamity which was afflicting him. The third kind is the madness of those who are possessed by the Muses; which taking hold of a delicate and virgin soul, and there inspiring frenzy, awakens lyrical and all other numbers; with these adorning the myriad actions of ancient heroes for the instruction of posterity. But he who, having no touch of the Muses' madness in his soul, comes to the door and thinks that he will get into the temple by the help of art-he, I say, and his poetry are not admitted; the sane man disappears and is nowhere when he enters into rivalry with the madman.

—Plato, Phaedrus, p. -1