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can say I feel, I think, I love ; but how does conscious- 

 ness infuse itself into the problem ? The human brain 

 is said to be the organ of thought and feeling ; when 

 we are hurt the brain feels it, when we ponder it is the 

 brain that thinks, when our passions or affections are 

 excited it is through the instrumentality of the brain. 

 Let us endeavor to be a little more precise here. I 

 hardly imagine that any profound scientific thinker who 

 has reflected upon the subject exists, who would not ad- 

 mit the extreme probability of the hypothesis, that for 

 every fact of consciousness, whether in the domain of 

 sense, of thought, or of emotion, a certain definite 

 molecular condition is set up in the brain ; that this re- 

 lation of physics to consciousness is invariable, so that, 

 given the state of the brain, the corresponding thought 

 or feeling might be inferred ; or, given the thought or 

 feeling, the corresponding state of the brain might be 

 inferred. But how inferred ? It is at bottom not a case 

 of logical inference at all, but of empirical association. 

 You may reply that many of the inferences of science 

 are of this character ; the inference, for example, that 

 an electric current of a given direction will deflect a 

 magnetic needle in a definite way ; but the cases differ 

 in this, that the passage from the current to the needle, 

 if not demonstrable, is thinkable, and that we entertain 

 no doubt as to the final mechanical solution of the prob- 

 lem ; but the passage from the physics of the brain to 

 the corresponding facts of consciousness is unthinka- 

 ble. Granted that a definite thought and a definite 

 molecular action in the brain occur simultaneously, we 

 do not possess the intellectual organ, nor, apparently, 

 any rudiment of the organ, which would enable us to 

 pass by a process of reasoning from the one phenome- 



