EVOLUTION DEFINED 9 



chance or whim. Whatever occurs comes as the resultant of 

 moving forces. Could we know and estimate these forces, we 

 should have, so far as our estimate is accurate and our logic 

 perfect, the gift of prophecy. Knowing the law, and knowing 

 the facts, we should foretell the results. To be able in some 

 degree to do this is the art of life. It is the ultimate end of 

 science, which finds its final purpose in human conduct. 



"A law," according to Darwin, "is the ascertained sequence 

 of events." The actual sequence of events it is, in fact, but 

 man knows nothing of what is necessary, only of what has been 

 ascertained to occur. Because human observation and logic 

 can be only partial no law of life can be fully stated. Because 

 the processes of human mind are human, with organic limita- 

 tions, the study of the mind itself becomes a part of the science 

 of bionomics. For it is itself an instrument or a combination 

 of instruments by which we acquire such knowledge of the 

 world outside of ourselves as may be needed in the art of living, 

 in the degree in which we are able to practice that art. 



The necessary sequence of events exists, whether we are able 

 to comprehend it or not. The fall of a leaf follows fixed laws 

 as surely as the motion of a planet. It falls by chance because 

 its short movement gives us no time for observation and calcu- 

 lation. It falls by chance because, its results being unim- 

 portant to us, we give no heed to the details of its motion. But 

 as the hairs of our head are all numbered, so are numbered all 

 the gyrations and undulations of every chance autumn leaf. 

 All processes in the universe are alike natural. The creation 

 of man or the growth of a state is as natural as the formation 

 of an apple or the growth of a snowbank. All are alike super- 

 natural, for they all rest on the huge unseen solidity of the 

 universe, the imperishability of matter, the conservation of 

 energy, and the immanence of law. 



We sometimes classify sciences as exact and inexact, in 



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accordance with our ability exactly to weigh forces and results. 

 The exact sciences deal with simple data accessible and capable 

 of measurement. The results of their interactions can be 

 reduced to mathematics. Because of their essential simplicity, 

 the mathematical sciences have been carried to great com- 

 parative perfection. It is easier to weigh an invisible planet 

 than to measure the force of heredity in a grain of corn. The 

 sciences of life are inexact because the human mind can never 



