X.] SENSATION AND THE SENSIFEROUS ORGANS. 261 



come to an end ; while phenomena of another order, 

 or immaterial states of consciousness, make their 

 appearance. How is the relation between the material 

 and the immaterial phenomena to be conceived? 

 This is the metaphysical problem of problems, and 

 the solutions which have been suggested have been 

 made the corner-stones of systems of philosophy. 

 Three mutually irreconcilable readings of the riddle 

 have been offered. 



The first is, that an immaterial substance of mind 

 exists ; and that it is affected by the mode of motion 

 of the sensorium in such a way as to give rise to the 

 sensation. 



The second is, that the sensation is a direct effect 

 of the mode of motion of the sensorium, brought 

 about without the intervention of any substance of 

 mind. 



The third is, that the sensation is neither directly 

 nor indirectly an effect of the mode of motion of the 

 sensorium, but that it has an independent cause. 

 Properly speaking, therefore, it is not an effect of 

 the motion of the sensorium, but a concomitant of it. 



As none of these hypotheses is capable of even 

 an approximation to demonstration, it is almost need- 

 less to remark that they have been severally held with 



words, to the phenomena of mind. Knowledge of the physical world, 

 or of one's own body and of objects external to it, is a system of 

 beliefs or judgments based on the sensations. The term "self" is 

 applied not only to the series of mental phenomena which constitute 

 the ego, but to the fragment of the physical world which is their con- 

 stant concomitant. The corporeal self, therefore, is part of the non- 

 ego ; and is objective in relation to the ego as subject. 



