What, indeed, does man know of himself?
Can he even once perceive himself completely, laid out as if in an illuminated glass case?
Does not nature keep much the most from him, even about his body, to spellbind and confine him in a proud, deceptive consciousness, far from the coils of the intestines, the quick current of the blood stream, and the involved tremors of the fibers? She threw away the key; and woe to the calamitous curiosity which might peer just once through a crack in the chamber of consciousness and look down, and sense that man rests upon the merciless, the greedy, the insatiable, the murderous, in the indifference of his ignorance-hanging in dreams, as it were, upon the back of a tiger.
In view of this, whence in all the world comes the urge for truth? Insofar as the individual wants to preserve himself against other individuals, in a natural state of affairs he employs the intellect mostly for simulation alone. But because man, out of need and boredom, wants to exist socially, herd-fashion, he requires a peace pact and he endeavors to banish at least the very crudest bellum omnium contra omnes (war of all against all) from his world.
— Excerpt taken from Nietzsche’s Thus Spoke Zarathustra