He may be mad, but there's method in his madness. There nearly always is method in madness. It's what drives men mad, being methodical.

Though this be madness, yet there is method in't.

Madness is the genius’ substitute for stupidity.

There is no great genius without a mixture of madness

Imperfection is beauty, madness is genius

Genius is the side effect of madness, rather than the reverse.

There nearly always is a method in madness.

To say that a great genius is half-mad, while recognizing his artistic prowess, is worth as much as saying that he was rheumatic, or that he suffered from diabetes. Madness, in fact, is a medical expression to which a balanced critic should pay no more heed than he would to the accusation of heresy brought by the theologian, or to the accusation of immorality brought by the public prosecutor.

Madness is the acme of intelligence.

Sometimes I feel sure he is as mad as a hatter and then, just as he is at his maddest, I find there is a method in his madness.

Between genius and madness there is often not the thickness of a hair.

Madness is somewhere between chaos and having a dream.

madness, in a higher sense, is the beginning of all wisdom

Genius is one of the many forms of insanity.