450 PROGRESS OF SCIENCE IN THE CENTURY. 



from the establishment of a penny-post between the 

 planets of the solar system.'' * This is one of the 

 linest specimens of ironical scientific literature since 

 science began. 



When the question is asked in this form : — Do the 

 formulae of biology, of physiology, of chemistry and 

 physics, suffice to restate the facts of mental life? 

 There is at present no manner of doubt that the 

 answer should be an emphatic " No." 



Whether the development (personal) and evolu- 

 tion (racial) of that synthesis which we call Mind 

 ( " the unity of manifold successive and simulta- 

 neous modes of consciousness in an individual 

 whole ") can be traced is another question, to which 

 the sanguine would — with some justification — an- 

 swer "Yes.'' 



Whether we shall ever be able to conceive how it is 

 that protoplasmic metabolism comes to be in certain 

 cases attended by consciousness (which we cannot posi- 

 tively define) is another question, answers to which 

 are mere matters of opinion. The correlation and 

 parallelism of metabolism and mentality, of neuroses 

 and psychoses must be admitted, but the two sets of 

 facts cannot be identified, and science as such has 

 at present no answer to give in regard to the nature 

 of the relation between them. We may simply state 

 the three metaphysical alternatives: — (a) that the 

 brain is the only real agency and consciousness one 

 of its phenomena; (b) that consciousness is the real- 

 ity of which the correlated brain-process is a phenom- 

 enon; or (c) that brain-process and consciousness are 

 two aspects of the same reality. 



Summary. — The physiologist who devotes himself 

 to the study of nervous functions often speaks as if 



