There have been many forces urging mankind onward in this long evolution. Religion has played a part. Love of country has played a part. Climate and the nature of the soil have been factors. Man's ever growing curiosity, his desire to know more of the life around him, has had much to do with it. I have put the ideals of religion and patriotism first, Jonathan, because I wanted you to see that they were by no means overlooked or forgotten, but in truth they ought not to be placed first. It is the verdict of all who have made a study of social evolution that, while these factors have exerted an important influence, back of them have been the material economic conditions.
In philosophy this is the basis of a very profound theory upon which many learned volumes have been written. It is generally called "The Materialistic Conception of History," but sometimes it is called "Economic Determinism" or "The Economic Interpretation of History." The first man to set forth the theory in a very clear and connected manner was Karl Marx, upon whose teachings the Socialists of the world have placed a great deal of reliance. I don't expect you to read all the heavy and learned books written upon this subject, for many of them require that a man must be specially trained in philosophy in order to understand them. For the present I shall be quite satisfied if you will read a ten-cent pamphlet called _The Communist Manifesto_, by Karl Marx and Frederick Engels and, along with that, the fourth, fifth and sixth chapters of my book, _Socialism_, about a hundred pages altogether. These will give you a fairly clear notion of the matter. I shall not mention the hard, scientific name of this philosophy again. I don't like big words if little ones will serve.
If you enjoy reading a good story, a novel that is full of romance and adventure, I would advise you to read _Before Adam_, by Jack London, a Socialist writer. It is a novel, but it is also a work of science. He gives an account of the life of the first men and shows how their whole existence depended upon the crude weapons and tools, sticks picked up in the forests, which they used. They couldn't live differently than they did, because they had no other means of getting a living. How a people make their living determines how they live.