It is certainly not the least charm of a theory that it is refutable; it is precisely thereby that it attracts the more subtle minds. It seems that the hundred-times-refuted theory of the "free will" owes its persistence to this charm alone; some one is always appearing who feels himself strong enough to refute it.
The most spiritual men, as the strongest, find their happiness where others would find their destruction: in the labyrinth, in hardness against themselves and others, in experiments. Their joy is self-conquest: asceticism becomes in them nature, need, and instinct. Difficult tasks are a privilege to them; to play with burdens that crush others, a recreation. Knowledge-a form of asceticism. They are the most venerable kind of man: that does not preclude their being the most cheerful and the kindliest.