Thus each generation of scientists accepts from its predecessors a trust for the future. Not only must it preserve the body of knowledge, but it must verify, amplify and enrich it. This is as true of the social scientist as it is of the natural scientist. The difference between them is that the natural scientist has worked out his technique and established his field, while the social scientist has reached only the threshold. 6. _Accumulating Social Knowledge_ Social knowledge is yet in its infancy. It is only within the century that Comte, Buckle, Marx, Spencer and other historians and sociologists have made an attempt to place the accumulations of social knowledge on a par with the accumulations of mathematical or chemical knowledge. Until some effort was made to study society in a scientific spirit, there was no reason for supposing that men might be able to cope with social ills or to prevent social disaster. Even to-day, while there is no longer any question as to the possibility of classifying social facts, and while sociology is regarded as a science of great promise, the feeling lingers that social events are fore-ordained. Many people feel to-day about social disaster as the men of the middle ages felt about the plague--that it is outside the field of man's preventive power. Another fatalistic school of thought holds that men learn their social lessons only through failure and disaster. According to the first line of thought it is useless to interfere with social processes because they are in the hands of the gods; according to the second, men will not interfere until they have been whipped into rebellion by the adverse conditions surrounding them. Men in the past have modified the course of human events in the most profound way. The first smelter of iron and the first constructor of a wheel began a series of events that is still molding social life. It is quite possible to say that these events were fore-ordained, but it is at least equally possible to reply that the same process of fore-ordination is still busy, and that the changes that it will make through the present generation will be at least as important as those which it has made in the preceding ages.