Page:Principles of Psychology (1890) v1.djvu/31

Rh We need not discuss here whether these writers in drawing their conclusion have done justice to all the premises involved in the cases they treat of. We quote their arguments only to show how they appeal to the principle that no actions but such as are done for an end, and show a choice of means, can be called indubitable expressions of Mind.

I shall then adopt this as the criterion by which to circumscribe the subject-matter of this work so far as action enters into it. Many nervous performances will therefore be unmentioned, as being purely physiological. Nor will the anatomy of the nervous system and organs of sense be described anew. The reader will find in H. N. Martin's 'Human Body,' in G. T. Ladd's 'Physiological Psychology,' and in all the other standard Anatomies and Physiologies, a mass of information which we must regard as preliminary and take for granted in the present work. Of the functions of the cerebral hemispheres, however, since they directly subserve consciousness, it will be well to give some little account.