The exaggeration of the harmony attributed to Nature aroused men to note its disharmonies. An optimistic view of natural benevolence was followed by a more honest, less romantic view of struggle and conflict in nature. After Helvetius and Bentham came Malthus and Darwin. The problem of morals is the problem of desire and intelligence. What is to be done with these facts of disharmony and conflict? After we have discovered the place and consequences of conflict in nature, we have still to discover its place and working in human need and thought. What is its office, its function, its _possibility_, or use? In general, the answer is simple. Conflict is the gadfly of thought. It stirs us to observation and memory. It instigates to invention. It shocks us out of sheep-like passivity, and sets us at noting and contriving. Not that it always effects this result; but that conflict is a _sine qua non_ of reflection and ingenuity. When this possibility of making use of conflict has once been noted, it is possible to utilize it systematically to substitute the arbitration of mind for that of brutal attack and brute collapse. But the tendency to take natural law for a norm of action which the supposedly scientific have inherited from eighteenth century rationalism leads to an idealization of the principle of conflict itself. Its office in promoting progress through arousing intelligence is overlooked, and it is erected into the generator of progress. Karl Marx borrowed from the dialectic of Hegel the idea of the necessity of a negative element, of opposition, for advance. He projected it into social affairs and reached the conclusion that all social development comes from conflict between classes, and that therefore class-warfare is to be cultivated. Hence a supposedly scientific form of the doctrine of social evolution preaches social hostility as the road to social harmony. It would be difficult to find a more striking instance of what happens when natural events are given a social and practical sanctification. Darwinism has been similarly used to justify war and the brutalities of competition for wealth and power.