"Why did God create human beings with two eyes, rather than with one or three or four?" a disciple once asked his master, Rabbi Mendel of Kotzk.
"Because human beings need no more and no less than two eyes," answered the master. "They need one eye for looking outward, at the world. And, they need a second eye for peering inward, into the self."
— Rabbi Mendel of Kotzk , The Community of Religions by Wayne Teasdale, editor, George Cairns, editor