president's address — SECTION J. 253 



manifestations of the same reality, they are still, as manifestations, 

 as far as possible from being identical with each other. And this 

 difference is equally fatal to the crude materialism expressed in the 

 saying that the brain secretes thought as the liver secretes bile. There 

 can be no true analogy between thought and the " tangible, ponderable, 

 visible " product of a bodily process. But, setting aside these crudities, 

 is the case for materialism improved when we are told (1) that mental 

 action is a mode of motion ; (2) that it is a manifestation of matter ; 

 (3) that it is a form of energy — like heat, light, or electricity ; (or 4) 

 that it is a function of the brain ? These statements are often shuffled 

 about as if they were interchangeable ; but it will be worth our while 

 to glance at each of them in turn. 



(1) A mental fact cannot be identified with a mode of motion. 

 Mobility is an essential property of material things ; apart from motion 

 we could not know them. It is through actual contact of his own 

 moving body and the bodies by which he is surrounded that the child 

 makes their acquaintance. But what is meant by the statement that 

 thought, or any mental process, is a mode of motion ? The physiologist 

 might pore till doomsday over the changes of the brain without being 

 made aware, if he were not aware otherwise, of the existence of mind. 

 He might trace, to a fuller extent than anyone has yet succeeded in 

 doing, the manner in which motion is flashed along the nerve fibres, 

 or stored as potential energy in the cell bodies. Could the whole 

 structure, with its ever-varying movements, be laid bare before him, 

 he would expect like movements in the future ; but were he strictly 

 confined to the investigation of matter in motion he could never from 

 this assert the presence or predict the advent of mind. Thus Tyndall 

 has justly said that " The passage from the physics of the brain to the 

 corresponding facts of consciousness is inconceivable as a result of 

 mechanics. AVere our minds and senses so expanded, strengthened, 

 and illuminated as to enable us to see and feel the very molecules of 

 the brain ; were we capable of following all their motions, the chasm 

 between the two classes of phenomena would still remain intellectually 

 impassable." (<=) And Herbert Spencer, though he has expressed his 

 formula of evolution in terms of matter and motion, has yet, in a well- 

 known passage, decisively rejected the belief that mind may be inter- 

 preted in terms of matter, declaring that, were he compelled to choose 

 between materialism and idealism, the latter alternative would seem 

 to him more acceptc>,ble.(/) Statements such as these emphasize the 

 difference between mental and material facts, and show how impossible 

 it is to reduce mind to motion or matter in motion. 



(2) A similar objection applies to the statement that mental action 

 is a manifestation of matter or material substance. A material thing 

 is made manifest to us through its properties, and w^e know it more 

 fully in proportion as we know them. But mental action is not one of 

 these properties. In attending exclusively to the bodily organism or 

 the brain, the physicist or physiologist abstracts from all knowledge 



(e) Fragments of Science II., pp. 86-7. 

 (/) Principles of Psychology, vol. I., pp. 158-9. 



