256 The Evolution Hypothesis. 



ing between the forces of the organism and the 

 mental operations embodied in thought. The fact 

 that in connexion with and through a bodily organi- 

 zation, the spiritual nature of man receives knowledge 

 of and acts on the external world, renders it certain 

 that there will be found remarkable correspondences 

 between the activities of the mind and the functions 

 of the body ; but it is quite a different thing to assert 

 that mental operations and physical forces are em- 

 braced under one law of correlation and equivalence. 

 " Yet," Mr. Spencer says, " there is no alternative but 

 to make the assertion : the facts which justify, or 

 rather which necessitate it being abundant and con- 

 spicuous." " Between the physical forces and the 

 sensations there exists a correlation like that between 

 the physical forces themselves." * This view is 

 reasoned out both in his First Principles and in his 

 Principles of Psychology with much fulness of argu- 

 ment and illustration. The cogency of the reasoning 

 is, however, greatly weakened by Mr. Spencer's re- 

 pudiation of the materialist theory. If it were 

 maintained that intellection is a mode of molecular 

 motion ; if the mental were accepted as merely phy- 

 sical, or if monism were reached from the opposite 

 side and the material held to be spiritual, one could 

 readily comprehend how the operations of mind might 

 be set in a series of correlations of physical force. 



* First Principles, 71. 



