CHAPTER II. 



NATURAL SELECTION, OR THE EVOLUTIONAL 

 VALUE OF THE INDIVIDUAL VARIATION. 



I SHALL begin this chapter by making some 

 remarks upon the place of the hypothesis in the 

 march of science. Those departments of knowledge 

 that are called Sciences have developed from small 

 beginnings by the application of general principles 

 or categories to the ascertained body of facts or 

 phenomena belonging to them. Certain phenomena 

 are perceived to be related to each other from having 

 certain features or properties in common. The 

 grouping of these phenomena in categories according 

 to their relations to one another is called generalising. 

 As the study of a science advances, and the known 

 facts increase in number and significance, it is found 

 that larger groupings may be made, as the relations 

 between the groups themselves are found to bring two 

 or more of them into a common category, or it is 

 perceived that the principles of grouping hitherto 

 employed require to be altered, and the categories 

 adjusted to accord with new acqusitions of knowledge. 

 Owing to the limitation of the human mind in regard 



to abstract or universal truth, a law of Nature must 



60 



