406 FRAGMENTS OF SCIENCE. 



for example, can say " I feel," " I think," " I love; " but 

 how does consciousness 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 pon- 

 der, or 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 there 

 exists a profound scientific thinker, who has reflected upon 

 the subject, unwilling to admit the extreme probability of 

 the hypothesis, that for every fact of consciousness, 

 whether in the domain of sense, thought, or emotion, a 

 definite molecular condition, of motion or structure, is set 

 up in the brain: or who would be disposed even to deny 

 that if the motion, or structure, be induced by internal 

 causes instead of external, the effect on consciousness will 

 be the same? Let any nerve, for example, be thrown by 

 morbid action into the precise state of motion which would 

 be communicated to it by the pulses of a heated body, 

 surely that nerve will declare itself hot the mind will 

 accept the subjective intimation exactly as if it were ob- 

 jective. The retina may be excited by purely mechanical 

 means. A blow on the eye causes a luminous flash, and 

 the mere pressure of the finger on the external ball produces 

 a star of light, which Newton compared to the circles on 

 a peacock's tail. Disease makes people see visions and 

 dream dreams; but, in all such cases, could we examine 

 the organs implicated, we should, on philosophical grounds, 

 expect to find them in that precise molecular condition 

 which the real objects, if present, would superinduce. 



The relation of physics to consciousness being thus in- 

 variable, it follows 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 would 

 be 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 conceivable, aud that 

 we entertain no doubt as to the final mechanical solution 

 of the problem. But the passage from the physics of the 



