840 THE AMERICAN JOURNAL OF SOCIOLOGY
It is only in investigations of man as he is now that facts can be dealt with at first hand.
MORE EXACT STUDY OF MIND NEEDED.
Rigid methods of research have until lately been confined to physics, astronomy, physiology, and other sciences ; and when applied to man they have been concerned rather with his physical than mental side. It is only recently that more exact methods have been used in the study of man's mind. These methods were opposed and ridiculed by extreme doctrinaires, but such opposition has ceased almost entirely, and where it does exist it is due either to ignorance or to mistakes liable to occur in the introdution of new methods.
If the study of man is to be worthy of the name, rigid methods must be applied to his mind as well as to his body. The most satisfactory and best method yet known is the psycho- physical method, introduced by Fechner and developed by Wundt into what is called "physiological psychology."
PSYCHO-PHYSICAL LABORATORY.
The first requisite to carry out this psycho-physical method of study is a laboratory containing instruments of precision.
In the study of man one of the greatest difficulties is the defectiveness and limitations of his senses. These defects have reference, not only to insufficiency of the senses to discover certain truths, but also to the errors they cause us to make.
The diurnal rotation of the earth, the distance of the stars, and the weight of the air are not appreciated by our senses, and often may seem contradictory to them. The sensations of cold and heat are not absolute, but merely relative to the temperature of our bodies, frequently misleading us. The illusions of sight, hearing, and touch point to the conclusion, accepted by modern psychology, that our ideas of the external world are the result of a long and unconscious education of the senses.
Science has destroyed the prejudice of the infallibility of the senses, and now finds its main help in the study of man to be in the use of instruments of precision. These not only correct the defects of the senses, but increase their scope, so that the results
