ix LIMITS OF NATURAL SELECTION IN MAN 207 



adopts the " well founded doctrine that life is the cause and 

 not the consequence of organisation." In his celebrated 

 article " On the Physical Basis of Life," however, he maintains 

 that life is a property of protoplasm, and that protoplasm 

 owes its properties to the nature and disposition of its 

 molecules. Hence he terms it "the matter of life," and 

 believes that all the physical properties of organised beings 

 are due to the physical properties of protoplasm. So far we 

 might, perhaps, follow him, but he does not stop here. He 

 proceeds to bridge over that chasm which Professor Tyndall 

 has declared to be " intellectually impassable," and, by means 

 which he states to be logical, arrives at the conclusion that 

 our "thoughts are the expression of molecular changes in that 

 matter of life which is the source of our other vital phenomena." 

 Not having been able to find any clue in Professor Huxley's 

 writings to the steps by which he passes from those vital 

 phenomena, which consists only, in their last analysis, of 

 movements of particles of matter, to those other phenomena 

 which we term thought, sensation, or consciousness, but 

 knowing that so positive an expression of opinion from him 

 will have great weight with many persons, I shall endeavour 

 to show, with as much brevity as is compatible with clearness, 

 that this theory is not only incapable of proof, but is also, as 

 it appears to me, inconsistent with accurate conceptions of 

 molecular physics. To do this, and in order further to 

 develop my views, I shall have to give a brief sketch of the 

 most recent speculations and discoveries as to the ultimate 

 nature and constitution of matter. 



The Nature of Matter 



It has been long seen by the deepest thinkers on the 

 subject, that atoms, considered as minute solid bodies from 

 which emanate the attractive and repulsive forces which give 

 what we term matter its properties, could serve no purpose 

 whatever ; since it is universally admitted that the supposed 

 atoms never touch each other, and it cannot be conceived that 

 these homogeneous, indivisible, solid units are themselves the 

 ultimate cause of the forces that emanate from their centres. 

 As, therefore, none of the properties of matter can be due to 

 the atoms themselves, but only to the forces which emanate 



