3 2o THE POPULAR SCIENCE MONTHLY. 



the whole constitution of the individual man, and his relations to the 

 "World external to him ; and aims to build it up with the materials 

 furnished by Experience of every kind, mental and bodily, normal 

 and abnormal ; ignoring no fact, however strange, that is attested by 

 valid evidence, and accepting none, however authoritatively sanc- 

 tioned, that will not stand the test of thorough scrutiny. 



It is very easy, and doubtless very pleasant, to dispose of " Cere- 

 bration " by a sneer ; but those who do so may be fairly called upon 

 in the first place to acquaint themselves with a class of facts which 

 they have never studied ; and, when they have examined them, may 

 be challenged to give some better and more scientific rationale of them 

 than that here offered. I should myself rejoice to welcome any new 

 light that metaphysics can throw upon such questions as the following : 



1. What other than "Physical Antecedents" excite those states of 

 Consciousness which we call Sensations, and the Pleasure and Pain 

 associated with them ? 



2. Does not all Psychological as well as Physiological probability 

 point to the identity of the Sensorial instrumentality through which 

 we become conscious (1) of a present Impression, and (2) of a remem- 

 bered Sensation ? 



3. If, then, a Visual perception be immediately dependent on a 

 Physical change in the Sensorium, excited (through the optic nerve) 

 by a Physical change in the Retina, is it not probable that a Visual 

 conception depends on a corresponding Physical change in the Sen- 

 sorium, called forth (through the "nerves of the internal senses") by 

 a Physical change in the cortical substance of the Cerebrum ? 



4. As Sensational Consciousness can be excited by " Physical An- 

 tecedents," why should not Ideational and Emotional f 



5. Is there not Psychological as well as Physiological evidence 

 that the excitement of the Ideational consciousness is the residt of a 

 series of Physical changes taking place in the Cerebrum, as the action 

 of a Mechanism created by its preformed Habits ? In what other way 

 are the facts (admitted by Psychologists of all schools) to be accounted 

 for, which indicate the suggestion of one Idea by another through a 

 chain of Associations, some links of which lie outside the " sphere of 

 consciousness ? " 



6. Is it conceivable that such an oft-recurring phenomenon as the 

 loss of some branch of acquired Knowledge, after a blow on the head 

 or a fever, is a mere coincidence f If not, on what other hypothesis 

 than that of " Physical antecedence" can the blow be the cause of this 

 Mental effect? 



7. Is there not as much evidence that " Physical Antecedents " may 

 produce Moral Pleasure and Pain, as that they produce Sensorial 

 Pleasure and Pain ? 



3. If in any case we admit Physical antecedence as the Cause (in 

 the ordinary language of Science) of Mental Phenomena, why not in 



