There is also a third kind of ...

There is also a third kind of madness, which is possession by the Muses, enters into a delicate and virgin soul, and there inspiring frenzy, awakens lyric... But he, who, not being inspired and having no touch of madness in his soul, comes to the door and thinks he will get into the temple by the help of art - he, I say, and his poetry are not admitted; the sane man is nowhere at all when he enters into rivalry with the madman.
There is also a third kind of madness, which is possession by the Muses, enters into a delicate and virgin soul, and there inspiring frenzy, awakens lyric... But he, who, not being inspired and having no touch of madness in his soul, comes to the door and thinks he will get into the temple by the help of art - he, I say, and his poetry are not admitted; the sane man is nowhere at all when he enters into rivalry with the madman.

Quotes from the same author

Love is a serious mental disease.
The man who makes everything that leads to happiness depends upon himself, and not upon other men, has adopted the very best plan for living happily. This is the man of moderation, the man of manly character and of wisdom.
Good actions give strength to ourselves and inspire good actions in others.
Cunning... is but the low mimic of wisdom.
A good decision is based on knowledge and not on numbers.