Z76 THE POPULAR SCIENCE MONTHLY. 



nation to push physical considerations to their utmost legitimate limit ; 

 and an acknowledgment that physical considerations do not lead to 

 the final explanation of all that we feel and know. This acknowledg- 

 ment, be it said in passing, was by no means made with the view of 

 providing room for the play of considerations other than physical. 

 The same intellectual duality, if I may use the phrase, manifests itself 

 in the following extract fi'om an article published in the Saturday Me- 

 vieio for August 4, 1860 : 



" The philosophy of the future will assuredly take more account than that 

 of the past of the dependence of thought and feeling on physical processes; and 

 it may be that the qualities of the mind will be studied through organic com- 

 binations as we now study the character of a force through the affections of 

 ordinary matter. We believe that every thought and every feeling has its defi- 

 nite mechanical correlative — that it is accompanied by a certain breaking up 

 and remarshaling of the atoms of the brain. This latter process is purely physi- 

 cal ; and, were the faculties we now possess sufBciently expanded, without the 

 creation of any new faculty, it would doubtless be within the range of our aug- 

 mented powers to infer from the molecular state of the brain the character of 

 the thought acting on it, and conversely to infer from the thought the exact 

 molecular condition of the brain. "We do not say — and this, as will be seen, is 

 all-important — that the inference here referred to would be an a priori one. 

 But by observing, with the faculties we assume, the state of the brain, and the 

 associated mental affections, both might be so tabulated side by side that, if one 

 were given, a mere reference to the table would declare the other. Our present 

 powers, it is true, shrivel into nothingness when brought to bear on such a 

 problem, but it is because of its complexity and our limits that this is the case. 

 The quality of the problem and of our powers are, we believe, so related that 

 a mere expansion of the latter would enable them to cope with the former. 

 Why, then, in scientific speculation should we turn our eyes exclusively to the 

 past? May it not be that a time is coming — ages no doubt distant, but still 

 advancing— when the dwellers upon this earth, starting from the gross human 

 brain of to-day as a rudiment, may be able to apply to these mighty questions 

 faculties of commensurate extent? Given the requisite expansibility to the 

 present senses and intelhgence of man — given also the time necessary for their 

 expansion — and this high goal may be attained. Development is all that is re- 

 quired, and not a change of quality. There need be no absolute breach of con- 

 tinuity between us and our loftier brothers yet to come. 



" We have guarded ourselves against saying that the inferring of thought 

 from material combinations and arrangements would be an inference a priori. 

 The inference meant would be the same in kind as that which the observation 

 of the effects of food and drink upon the mind would enable us to make, differ- 

 ing only from the latter in the degree of analytical insight which we suppose 

 attained. Given the masses and distances of the planets, we can infer the per- 

 turbations consequent on their mutual attractions. Given the nature of a dis- 

 turbance in water, air, or ether — knowing the physical quahties of the medium 

 — we can infer how its particles will he affected. In all this we deal with physi- 

 cal laws. The mind runs with certainty along the line of thoughts which con- 

 nect the phenomena, and from beginning to end there is no break in the chain. 

 But when we endeavor to pass by a similar process from the phenomena of 

 physics to those of thought, we meet a problem which transcends any conceiv- 



