This is a history book. Its earliest stages, its course, and laws may be studied; also its influence on individuals and their reaction on it. It is our present purpose so to study it. We have to recognize it as one of the chief forces by which a society is made to be what it is. Out of the unconscious experiment which every repetition of the ways includes, there issues pleasure or pain, and then, so far as the men are capable of reflection, convictions that the ways are conducive to societal welfare. These two experiences are not the same. The most uncivilized men, both in the food quest and in war, do things which are painful, but which have been found to be expedient. Perhaps these cases teach the sense of social welfare better than those which are pleasurable and favorable to welfare. The former cases call for some intelligent reflection on experience.