Summary. This is an orderly world, in which everything has a cause. All events are connected in a chain of causes and effects. Human beings live in this world of natural law and are subject to it. Human life is completely within this world of law and order and is a part of it. Education is possible only because we can change human beings by having influences act upon them.

Individuals receive their original traits from their ancestors, probably as parts or units. Mendelism is the doctrine of the pure transmission of unit characters. Eugenics is the science of improving the human race by selective breeding. An individual’s life is the result of the interaction of his hereditary characteristics and his environment.

CLASS EXERCISES

  1. Try to find rock containing the remains of animals. You can get information on such matters from a textbook on geology.
  2. Read in a geology about the different geological epochs in the history of the earth.
  3. Make a comparison of the length of infancy in the lower animals and in man. What is the significance of what you find? What advantage does it give man?
  4. What is natural selection? How does it lead to change in animals? Does natural selection still operate among human beings? (See a modern textbook on zoölogy.)
  5. By observation and from consulting a zoölogy, learn about the different classes of animal forms, from low forms to high forms.
  6. By studying domestic animals, see what you can learn about heredity. Enumerate all the points that you find bearing upon heredity.
  7. In a similar way, make a study of heredity in your family. Consider such characteristics as height, weight, shape of head, shape of nose, hair and eye color. Can you find any evidence of the inheritance of mental traits?
  8. Make a complete outline of Chapter [II].

REFERENCES FOR CLASS READING

CHAPTER III
MIND AND BODY

Gross Dependence. The relation of mind to body has always been an interesting one to man. This is partly because of the connection of the question with that of life after death. An old idea of this relation, almost universally held till recently, was that the mind or spirit lived in the body but was more or less independent of the body. The body has been looked upon as a hindrance to the mind or spirit. Science knows nothing about the existence of spirits apart from bodies. The belief that after death the mind lives on is a matter of faith and not of science. Whether one believes in an existence of the mind after death of the body, depends on one’s religious faith. There is no scientific evidence one way or the other. The only mind that science knows anything about is bound up very closely with body. This is not saying that there is no existence of spirit apart from body, but that at present such existence is beyond the realm of science.

The dependence of mind upon body in a general way is evident to every one, upon the most general observation and thought. We know the effect on the mind of disease, of good health, of hunger, of fatigue, of overwork, of severe bodily injury, of blindness or deafness. We have, perhaps, seen some one struck upon the head by a club, or run over by an automobile, and have noted the tremendous consequences to the person’s mind. In such cases it sometimes happens that, as far as we can see, there is no longer any mind in connection with that body. The most casual observation, then, shows that mind and body are in some way most intimately related.

Finer Dependence. Let us note this relation more in detail, and, in particular, see just which part of the body it is that is connected with the mind. First of all, we note the dependence of mind upon sense organs. We see only with our eyes. If we close the eyelids, we cannot see. If we are born blind, or if injury or disease destroys the retinas of the eyes or makes the eyes opaque so that light cannot pass through to the retinas, then we cannot see.