It was not an ideal world in which they found themselves. The greater part of the people were serfs or "villains," farm-hands who were as much a part of the soil upon which they lived as the cows and sheep whose stables they shared. Their fate was not particularly happy nor was it particularly unhappy. But what was one to do? The good Lord who ruled the world of the Middle Ages had undoubtedly ordered everything for the best. If He, in his wisdom, had decided that there must be both knights and serfs, it was not the duty of these faithful sons of the church to question the arrangement. The serfs therefore did not complain but when they were too hard driven, they would die off like cattle which are not fed and stabled in the right way, and then something would be hastily done to better their condition. But if the progress of the world had been left to the serf and his feudal master, we would still be living after the fashion of the twelfth century, saying "abracadabra" when we tried to stop a tooth-ache, and feeling a deep contempt and hatred for the dentist who offered to help us with his "science," which most likely was of Mohammedan or heathenish origin and therefore both wicked and useless. When you grow up you will discover that many people do not believe in "progress" and they will prove to you by the terrible deeds of some of our own contemporaries that "the world does not change." But I hope that you will not pay much attention to such talk. You see, it took our ancestors almost a million years to learn how to walk on their hind legs. Other centuries had to go by before their animal-like grunts developed into an understandable language. Writing--the art of preserving our ideas for the benefit of future generations, without which no progress is possible was invented only four thousand years ago. The idea of turning the forces of nature into the obedient servants of man was quite new in the days of your own grandfather. It seems to me, therefore, that we are making progress at an unheard-of rate of speed. Perhaps we have paid a little too much attention to the mere physical comforts of life. That will change in due course of time and we shall then attack the problems which are not related to health and to wages and plumbing and machinery in general.