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 be examined—the relation of the mind to the body.

According to the definition I am aiming at, psychology would be the science of internal facts, while the other sciences deal with the external. Psychology, it has also been said, has as its instrument introspection, while the natural sciences work with the eye, the touch, the ear—that is to say, with the senses of extrospection.

To this distinction, I reply that in all sciences there exist but two things: sensations and the consciousness which accompanies them. A sensation may belong to the inner or the outer world through accidental reasons, without any change in its nature; the sensation of the outer world is the social sensation which we share with our fellows. If the excitant which provokes it is included in our nervous system, it is the sensation which becomes individual, hidden to all except ourselves, and constituting a microcosm by the side of a macrocosm. What importance can this have, since all the difference depends on the position occupied by the excitant?

But we are persistently told: there are in reality two ways of arriving at the cognition of objects—from within and from without. These two ways are as opposite as the right and wrong side of a stuff. It is in this sense that psychology is the science of the within and looks at