EVOLUTION THE MASTER-KEY 



completely failed when they attempted to show 

 how this end may be attained. The reason for 

 this failure is evident. These thinkers were unable 

 to make their science more than empirical, more 

 than an inference from the facts of human life as 

 observed by all. It was thus hardly worthy to 

 be called scientific. But the new ethics grounds 

 the principles of morality in the facts of life and 

 mind and society. It is precisely because of the 

 thirty years he spent on these studies that Spencer 

 was enabled to reach his goal ; and this is true 

 even though he himself regretted that the princi- 

 ples of evolution had not furnished him, in this 

 final inquiry, with as much guidance as he had 

 hoped. 



Spencer was the first to make explicit the as- 

 sumption which underlies all ethical systems, the 

 assumption that life is worth living. This I will 

 not further examine until we come to discuss 

 evolution and optimism. Given this primary 

 datum, we are enabled to frame a definition of the 

 best conduct. If life, on the whole, be worth 

 living, "that conduct is best which achieves the 

 greatest totality of life in self, in offspring, and in 

 fellow-men." [Let us mark the inclusion of self in 

 this definition, for it prepares us for some consid- 

 eration as to the ultimate relation between egoism 

 and altruism.] This definition must, of course, be 

 interpreted in its highest and most liberal sense, as 

 its author states in the context. Life must gain in 

 " breadth " as well as " length." It must be " com- 

 264 



