Insanity destroys reason, but not wit.
For virtue's self may too much zeal be had; the worst of madmen is a saint run mad.
I doubt if a single individual could be found from the whole of mankind free from some form of insanity. The only difference is one of degree. A man who sees a gourd and takes it for his wife is called insane because this happens to very few people.
Whom God wishes to destroy, he first makes mad.
A man should not strive to eliminate his complexes, but to get into accord with them; they are legitimately what directs his conduct in the world.
Insanity is doing the same thing in the same way and expecting a different outcome.
I saw the best minds of my generation destroyed by madness, starving hysterical naked.
All of us are crazy in one way or another.
Better mad with the rest of the world than wise alone.
What is madness but nobility of soul. At odds with circumstance?
Insanity is often the logic of an accurate mind overtasked.
Though this be madness, yet there is method in it. [Hamlet]