See John Leslie, "The Prerequisites of Life in Our Universe," in Newton and the New Direction in Science, ed. G. V. <!g>Coyne and and J. Zycinski M. Heller (Vatican City State: Vatican Observatory, 1988). See also Stephen W. <!g>Hawking, A Brief History of Time: From the <!g>Big Bang to Black Holes (New York: Bantam Books, 1988).