According to the stories of many cultures, the human beginning was a time of ease and wonder, free from hard labor, struggle, strife, and the alienation and fragmentation we know today. Sometimes this perfection is projected into the future—a New Jerusalem descending upon the earth, the city of God, or a heaven we enter after death. Sometimes it is viewed as the possible result of human effort, a tradition spanning from Plato's Republic (ca. 360 B.C.E.; Hamilton and Cairns, 1969) and Thomas Moore's Utopia (1516), to James Hilton's Shangri-La, (1933) and B. F. Skinner's Walden Two (1948), among many others.