Joseph Campbell, The Masks of God, Vol. III: Occidental Mythology, p. 522

"The adventure of the Grail––the quest within for those creative values by which the Waste Land is redeemed––has become today for each the unavoidable task; for, as there is no more any fixed horizon, there is no more any fixed center, any Mecca, Rome, or Jerusalem. Our circle today is that announced, c. 1450, by Nicholas Cusanus: whose circumference is nowhere and whose center is everywhere; the circle of infinite radius, which is also a straight line."