The Story of the Mind

make sure of the results which they get by other methods. For example, the natural scientist, the botanist, let us say, and the physical scientist, the electrician, say, can not observe the plants or the electric sparks without really using his introspection upon what is before him. The light from the plant has to go into his brain and leave a certain effect in his mind, and then he has to use introspection to report what he sees. The astrono-WHAT OUR MINDS HAVE IN COMMON. 9 mer who has bad eyes can not observe the stars well or discover the facts about them, because his introspection in reporting what he sees proceeds on the imperfect and distorted images coming in from his defective .eyesight. So a man given to exaggeration, who is not able to report truthfully what he remembers, can not be a good botanist, since this defect in introspection will render his observation of the plants unreliable. In practice the introspective method has been most important, and the development of psychol- ogy has been up-to very recently mainly due to its use. As a consequence, there are many gen- eral principles of mental action and many laws of mental growth already discovered which should in the first instance engage our attention. They constitute the main framework of the building; and we should master them well before we go on to find the various applications which they have in the other departments of the subject.