28 INTERPRETATIONS OF NATURE. 
phy. It isa verifiable fact that every expression of con- 
sciousness,—every sensation, thought and emotion—is 
manifested through, and inseparably associated with a 
nervous mechanism ; it is also a fact that every modifica- 
tion of this mechanism, every change in its material con- 
formation—whether wrought by the favorable processes 
of development or by the repressive influences of injury 
or disease—affects the expressions of mental life, and 
thus favors the belief that the conscious mind ‘“‘ has its 
correlative in the physics of the brain.” 
Thus far, science feels its way secure, but it ventures 
no further; it beholds the ‘‘association of two classes 
of phenomena’’—but it gives no explanation of their 
‘‘bond of union.’ ‘*‘ Wedo not possess,’ says Tyndall, 
‘the intellectual organ, nor apparently any rudiment 
of the organ, which would enable us to pass, by a pro- 
cess of reasoning, from the one to the other. They ap- 
pear together, but we do not know why. Were our 
minds and senses so expanded, strengthened, and il- 
luminated as to enable us to see and feel the very mole- 
cules of the brain; were we capable of following all 
their motions, all their groupings, all their electric dis- 
charges, if such there be; and were we intimately ac- 
quainted with the corresponding states of thought and 
feeling, we should be as far as ever from the solution of 
the problem,—‘ How are these physical processes con- 
nected with the facts of consciousness?’ The chasm 
between the two classes of phenomena would still re- 
main intellectually impassable.’’ ‘‘The passage from 
the physics of the brain to the corresponding facts of 
consciousness is unthinkable.”’ 
That, which thus defies the analytic methods of sci- 
ence, is presented to the mind of the metaphysical phil- 
osopher as an independent and immortal soul, having 
the attributes of personality. This shadowy but real 
being is associated with and made manifest through the 
