CONTROVERSY AND PROGRESS. 69 



may be regarded as a scientific theory, devised to 

 explain the origination of the higher from the lower, 

 the more complex and differentiated from the simple 

 and undifferentiated, in inorganic and organic bod- 

 ies, or it may be viewed as a philosophical system, de- 

 signed to explain the manifold phenomena of mat- 

 ter and life by the operation of secondary causes 

 alone, to the exclusion of a personal Creator. In 

 the restricted sense in which we are considering it, it 

 is a scientific hypothesis intended to explain the ori- 

 gin and transmutation of species in the animal and 

 vegetable worlds, by laws and processes disclosed by 

 the study of nature. 



Important as it is, however, it is not always an 

 easy matter to keep the scientific theory separated 

 from the philosophical system. Hence, naturalists 

 and philosophers are continually intruding on each 

 other's territory. The naturalist philosophizes, 

 and the philosopher, if I may give a new meaning 

 to an old word, naturalizes. For naturalists and 

 physicists, as all are aware, are very much given to 

 making excursions into the domain of metaphysics 

 and to substituting speculations for rigid inductions 

 from observed facts. 



And metaphysicians sin in a similar manner by 

 attempting to explain, by methods of their own, the 

 various phenomena of the material world, and in 

 seeking by simple a priori reasons to evolve from 

 their inner consciousness a logical system of the 

 physical universe. The result is inextricable con- 

 fusion and errors without number. It is neither 

 science nor philosophy, but a mixtum compositum, 



