Great minds are related to the brief span of time during which they live as great buildings are to a little square in which they stand: you cannot see them in all their magnitude because you are standing too close to them.
Genius is, to be sure, not a matter of arbitrariness, but rather of freedom, just as wit, love, and faith, which once shall become arts and disciplines. We should demand genius from everybody, without, however, expecting it.
All the means of action -- the shapeless masses -- the materials -- lie everywhere about us. What we need is the celestial fire to change the flint into the transparent crystal, bright and clear. That fire is genius.
All of us, you, your children, your neighbors and their children are everyday geniuses, even though the fact is unnoticed and unremembered by everyone. That's probably because school hasn't encouraged us to notice what's hidden inside us waiting for the right environment to express itself.
Saying that a great genius is mad, while at the same time recognizing his artistic worth, is like saying that he had rheumatism or suffered from diabetes. Madness, in fact, is a medical term that can claim no more notice from the objective critic than he grants the charge of heresy raised by the theologian, or the charge of immorality raised by the police.
Unpretending mediocrity is good, and genius is glorious; but a weak flavor of genius in an essentially common person is detestable. It spoils the grand neutrality of a commonplace character, as the rinsings of an unwashed wine-glass spoil a draught of fair water.