We may fairly say that all this is merely a development of and an improvement upon the plain man’s knowledge of minds and of bodies.  There is no normal man who does not know that his mind is more intimately related to his body than it is to other bodies.  We all distinguish between our ideas of things and the external things they represent, and we believe that our knowledge of things comes to us through the avenues of the senses.  Must we not open our eyes to see, and unstop our ears to hear?  We all know that we do not perceive other minds directly, but must infer their contents from what takes place in the bodies to which they are referred—­from words and actions.  Moreover, we know that a knowledge of the outer world and of other minds is built up gradually, and we never think of an infant as knowing what a man knows, much as we are inclined to overrate the minds of infants.

The fact that the plain man and the psychologist do not greatly differ in their point of view must impress every one who is charged with the task of introducing students to the study of psychology and philosophy.  It is rather an easy thing to make them follow the reasonings of the psychologist, so long as he avoids metaphysical reflections.  The assumptions which he makes seem to them not unreasonable; and, as for his methods of investigation, there is no one of them which they have not already employed themselves in a more or less blundering way.  They have had recourse to introspection, i.e. they have noticed the phenomena of their own minds; they have made use of the objective method, i.e. they have observed the signs of mind exhibited by other persons and by the brutes; they have sometimes experimented—­this is done by the schoolgirl who tries to find out how best to tease her roommate, and by the boy who covers and uncovers his ears in church to make the preacher sing a tune.

It may not be easy to make men good psychologists, but it is certainly not difficult to make them understand what the psychologist is doing and to make them realize the value of his work.  He, like the workers in the other natural sciences, takes for granted the world of the plain man, the world of material things in space and time and of minds related to those material things.  But when it is a question of introducing the student to the reflections of the philosophers the case is very different.  We seem to be enticing him into a new and a strange world, and he is apt to be filled with suspicion and distrust.  The most familiar things take on an unfamiliar aspect, and questions are raised which it strikes the unreflective man as highly absurd even to propose.  Of this world of reflective thought I shall say just a word in what follows.

11.  REFLECTIVE THOUGHT.—­If we ask our neighbor to meet us somewhere at a given hour, he has no difficulty in understanding what we have requested him to do.  If he wishes to do so, he can be on the spot at the proper moment.  He may never have asked himself in his whole life what he means by space and by time.  He may be quite ignorant that thoughtful men have disputed concerning the nature of these for centuries past.