THE NATURE OF LIFE 11 



what we call the life of the organism. In considering what is 

 the meaning of all this we must remember that, primarily at any 

 rate, every living thing exists for its own benefit, and that 

 living, like virtue, is its own reward. The organism also, 

 however, exists for the benefit of future generations, to which 

 it may hand on the lamp of life before its own flame is finally 

 extinguished. There is a race life as well as an individual life, 

 and we cannot realize too clearly that in the economy of nature 

 the former is of infinitely greater importance than the latter. 



The ideas which we have just been considering are by no 

 means of modern origin. More than' three centuries ago the 

 philosopher Descartes endeavoured to explain the human body 

 as a machine, but as a machine under the control of the " soul," 

 which he curiously located in that part of the brain known as 

 the pineal gland. His ideas of physiology, however, were, 

 naturally, of the crudest description, and immense strides have 

 been made in this direction since his time. Chemists and 

 physicists have helped us much towards a correct understanding 

 of the living mechanism, but when they have done their best it 

 may well be that the question " What is Life? " will still remain 

 unanswered, and that we may still have to take refuge in the 

 idea of an unknown " soul " to explain the difference between 

 living and not-living things. The " soul " of Descartes' 

 philosophy corresponds more or less closely with the " vital 

 force " of some more recent writers and the " entelechy " l of 

 others, but whatever term we employ it must be rather as a 

 cloak for our ignorance than as an expression of any definite 

 opinion as to what it is that really animates the living body. 



1 Vide Driesch, " The Science and Philosophy of the Organism," (London, 

 A. & C. Black, 1908), Vol. 2, pp. 137, 138. 



