To learn to see- to accustom the eye to calmness, to patience, and to allow things to come up to it; to defer judgment, and to acquire the habit of a… - Friedrich Nietzsche

From experience. That something is irrational is no argument against its existence, but rather a condition for it.

If each us had a different kind of sense perception — if we could only perceive things now as a bird, now as a worm, now as a plant, or if one of us saw a stimulus as red, another as blue, while a third even heard the same stimulus as a sound — then no one would speak of such a regularity of nature, rather, nature would be grasped only as a creation which is subjective in the highest degree. After all, what is a law of nature as such for us? We are not acquainted with it in itself, but only with its effects, which means in its relation to other laws of nature — which, in turn, are known to us only as sums of relations. Therefore all these relations always refer again to others and are thoroughly incomprehensible to us in their essence.

He who speaks a bit of a foreign language has more delight in it than he who speaks it well; pleasure goes along with superficial knowledge.