LIMITS OF OUR KNOWLEDGE OF NATURE. 29 



knowledge of the brain leaves us with regard to the origin of the low- 

 est mental phenomena, and the complete solution of the highest prob- 

 lems of the physical world which we get from such knowledo-e. A 

 brain that should, from one cause or another, be unconscious — for in- 

 stance, one that should sleep without dreaming — would, had we astro- 

 nomical knowledge of it, hold no secret ; and, if we possessed astro- 

 nomical knowledge of the rest of the body also, then the whole human 

 machine, with its respiration, its heart-beats, its exchanges of materials, 

 its heat, etc. — in short, every thing short of the essence of matter and 

 force, would be fully deciphered. The dreamless sleeper is compre- 

 hensible to us, like the universe previous to consciousness. But, as, on 

 the first awakening of consciousness, the world became doubly incom- 

 prehensible, so too is it with the sleeper, at the first appearance of a 

 faint imasje in dreamino;. 



The irreconcilable conflict of the mechanical view of the universe 

 with freedom of will, and hence indirectly with ethics, is no doubt a 

 matter of high importance. The ingenuity of thinkers in all times has 

 been exhausted in trying to reconcile them, and this question will 

 afford exercise to the mind of man forever. To say nothing of the 

 fact that free-wall may be denied, whereas pleasure and pain are un- 

 questionable ; desire, which gives the impetus to exertion, and hence 

 gives occasion to act, or not to act, is necessarily preceded by sense- 

 impressions. Hence it is to the problem of sensation, and not, as I 

 have once said, to that of free-will, that analytical mechanics leads. 



And here is the other limit of our knowledge of Nature. It is no 

 less absolute than the first limit. For two thousand years, despite all 

 the advances made by natural science, mankind has made no sub- 

 stantial progress toward the understanding of matter and force, any 

 more than toward the understanding of mental activity from its ma- 

 terial conditions. And so will it ever be. Even the Mind imagined 

 by Laplace, with its universal formula, would, in its efforts to over- 

 step these limits, be like an aeronaut essaying to reach the moon. In 

 its world of mobile atoms, the cerebral atoms are in motion indeed, 

 but it is a dumb show. This Mind views their hosts, and sees them 

 crossing each other's course, but does not understand their pantomime ; 

 they think not for him, and hence, as we have already seen, the world 

 of this Mind is still meaningless. 



In this Mind we have the measure of our own capacity, or rather 

 our impotence. Our knowledge of Nature is thus shut up between 

 two limits, the one forevermore determining our incapacity to compre- 

 hend matter and force, the other determining our inability to under- 

 stand mental facts from their material conditions. Between these 

 limits the man of science is lord and master ; he dismembers and builds 

 up, and no one durst say wherein his knowledge and his power are 

 circumscribed. Beyond these limits he cannot now, nor can he 

 ever, go. 



