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from some strange region^ refusing to be accounted for_, or to 
be explained away. Tbe mental power developed simulta- 
neously witb molecular changes in the brain is^ therefore, not 
a phasis of the material energy developed. It cannot be com- 
puted in foot-pounds. Consciousness on this view/^ says 
Tyndall, in the article already cited, is a kind of by-product, 
inexpressible in terms of force and motion, and unessential to 
the molecular changes going on in the brain. Except the 
term by-product,'’^ which implies causal connexion, we may 
accept this statement. A little further on in the same paper 
Tyndall quotes himself as inquiring, What is the causal con- 
nexion between molecular motions and states of conscious- 
ness?^^ My answer,^’ he continues, ^^is, I do not see the 
connexion, nor am I acquainted with anybody who does."” It 
is no explanation to say that the objective and subjective are 
two sides of one and the same phenomenon. Why should the 
phenomenon have two sides ? This is the very core of the 
difficulty. There are plenty of molecular motions which do 
not exhibit this two-sidedness. Does water think or feel 
when it runs into frost-ferns upon a window pane ? If not, 
why should the molecular motion of the brain be yoked to 
this mysterious companion — consciousness ? We can form a 
coherent picture of all the purely physical processes, — the 
stirring of the brain, the thrilling of the nerves, the discharg- 
ing of the muscles, and all the subsequent motions of the 
organism. We are here dealing with mechanical problems, 
which are mentally presentable. But we can form no picture 
of the process whereby consciousness emerges, either as a 
necessary link, or as an accidental by-product, of this series of 
actions. The reverse process of the production of motion by 
consciousness is equally unpresentable to the mind. We are 
here, in fact, on the boundary line of the intellect, where the 
ordinary canons of science fail to extricate us from difficulty. 
It is a favourite saying of the ultra school of Materialists 
that the brain secretes thought as the liver secretes bile. In 
the light of the foregoing observations we may perceive the 
full absurdity of such a statement, as of others of the like 
coinage. Such language has no real significance, except, 
indeed, as displaying that the speaker who employs it has 
failed to grasp the facts of the case. Our conclusion, then, is 
that the association of the human mind with a physical 
organism is not ground on which the philosopher is warranted 
in regarding mind as the mere effiuence and expression of 
material changes. 
As I have quoted largely from Professor Tyndall, it is as 
well to say, that whilst glad of him as a useful ally in what 
