The facts are as follows: People have been here on the earth a very long time, millions of years they think. Machines they have had for only a very short time, or, as you now see them, for only two generations. Before they had machines nearly everyone tilled the soil. There was no industry save handicraft. In the space of one hundred years these conditions have so remarkably changed that now only half the people are required to till the soil; the other half live by industry. This does not mean what you thought at first; it does not mean that half the fields have been abandoned so that half the people might go into industry. You are careful to get this straight, for it is very important. On the contrary, since machines appeared whole new continents of land have been opened to cultivation. This was necessary in order to feed the industrial workers who live in cities, far off from fields, and buy their food, whereas formerly everyone generally speaking produced his own food, even the people of what once were called cities going forth seasonally to till and reap the earth. Actually, the number of people engaged in agriculture has greatly increased; yet it is only half the population where before it was the whole of it. What does this mean? It means that since the advent of machines the human race has enormously increased in number; it has so increased that the half of it which now is agricultural is greater than the whole of it was before. The new, non-agricultural half is the industrial part: it is the part that serves machines. This fact is so astonishing that you wish to verify it. You ask them what would happen if all the machines in the world should vanish suddenly away. Their answer is that half the people living would perish in a week. And that is what you thought. What may you deduce from these facts? First, you will be amused that people are so naïve as to think they make machines. Then you may say there are two kinds of people here, agricultural and industrial. The earth makes one kind; machines make the other. And you will feel as sure of this as if you had proved it to your senses when you have looked at a typical industrial city where people live densely in compacted habitations with no visible errand on earth but to run to and fro tending the machines that hum night and day in the factories. Those tall, cylindrical, erupting forms called smokestacks will appear to you as generative symbols. If they were not there, neither would the people be there. Not only would the people not be there. They would be nowhere. They could never have existed. If the smokestacks disappeared, so would all these people, the industrial part of the population, leaving only the agricultural part—the part belonging to the soil—as it was before.