CHAPTER I. 

 THE PROBLEMS AND CONCEPTS OF EVOLUTION. 



INTRODUCTION. 



The following chapters give the results derived from an attempt to analyze 

 the phenomena of evolution, using chrysomelid beetles of the genus Leptino- 

 tarsa as materials for investigation. In this investigation I am interested only 

 in processes or reactions productive of evolutionary phenomena, or that are of 

 experimentally proven importance in evolution, because they are the modus 

 operandi of the evolution of living substance and are universal in action. The 

 chrysomelid beetles and their transmuted products and characters are of 

 interest only to the extent that they have been convenient reagents for use in 

 the investigation. 



It is important to understand clearly the general philosophical conceptions 

 from which we interpret nature and which guide our efforts in the prosecution 

 of research, since this will largely determine the logical, philosophical, and 

 experimental methods used in investigation and the hypotheses created. It is 

 sufficient to state my own position ; others must decide for themselves to what 

 extent they can interpret the phenomena of organic life upon the same basis. 



In the absence of any evidence to the contrary, the physical world, as known 

 to us from our sense perceptions, is all that exists, and the general philosophical 

 postulate from which I must approach any investigation of nature is that of 

 positive materialism, and all activities, from the lowest to the highest, from 

 this postulate are, in the end, capable of statement and explanation upon purely 

 mechanistic physical relations and reactions. 



It is our task to interpret and understand ourselves and nature from the- 

 operation of known physical agencies. When we have entirely and honestly 

 exhausted all of the possibilities of physical science, when physical science shall 

 have reached its end, if there remain phenomena not capable of statement in 

 terms of the physical factors of the universe, it may then be necessary to search 

 for ultra-physical causes. At present we fall so far short of exhausting the 

 possible applications of physical knowledge to the problems of living bodies 

 that there is no valid excuse for even suggesting the existence of non-physical 

 agents or causes which find expression in living material objects and reactions. 



PHYSICAL CONCEPTION OF LIFE. 



In the contact zones between the lithosphere, the hydrosphere, and the atmos- 

 phere of this planet, marvelously complex integrations of matter occur, pre- 

 senting activities and reactions that are conspicuously unlike, in their totality,, 

 anything else found in nature, but upon analysis there has been found only the 

 action of physical principles in these living bodies, combined in an immensely 

 complex system of interacting factors, collectively presenting end or superficial 

 aspects, which to some seem sharply and finally to differentiate this product of 



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