Dwight Longenecker

Because we are limited in our knowledge, even the sanest of us are slightly insane. Our limitations are a kind of madness, and we can only choose to deny we are mad, and so descend into a dark spiral of total insanity, or accept we are mad and embark on a quest to regain our true and wholesome sanity

Like Achilles, the hero who forgot his heel, or like Icarus who, flying close to the sun, forgot that his wings were made of wax, we should be wary when triumphant ideas seem unassailable, for then there is all the more reason to predict their downfall.