A life without adventure is likely to be unsatisfying, but a life in which adventure is allowed to take whatever form it will is sure to be short. BERTRAND RUSSELL, "Social Cohesion and Human Nature", Authority and the Individual A religious creed differs from a scientific theory in claiming to embody eternal and absolutely certain truth, whereas science is always tentative, expecting that modification in its present theories will sooner or later be found necessary, and aware that its method is one which is logically incapable of arriving at a complete and final demonstration. - Bertrand Russell