"Human beings are bees of the invisible," wrote the great poet Rainer Maria Rilke in a letter to his friend Witold Hulewicz on November 13, 1925, "passionately we plunder the honey of the visible in order to gather it in the great golden hive of the invisible." Just as the honeybee plays an integral part in the flourishing of Nature, so likewise the human being must fulfill an essential role in the harmony of the cosmos. What is this role? To answer this question, we must know what the human being is. Humankind's marvelous advancement in scientific knowledge has come at the cost of...