Evolution 413 



tinuity, namely, that the laws of nature never vary. Yet we find all 

 biologists agreeing that the law of continuity has been broken, by the 

 fact that living forms must have once sprung from non-living, a con- 

 dition now no longer true. This is the great "heresy" of evolutionary 

 science. As life and mentality do not now operate as they once did, 

 when, where, and how did they begin? 



13. No Satisfactory Theory of Evolution. 



No theory of evolution yet propounded is satisfactory because none 

 has satisfied the requirements set forth above. 



14. Impossibility of a Satisfactory Physical Explanation. 



There exist certain rays, known as infra-red and ultra-violet, which 

 no human eye can see ; yet, these rays can be proved to exist by the 

 physicist. If the ultra-violet rays are thrown upon a group of brown 

 ants they will immediately scatter quite hurriedly, thus demonstrating 

 their ability to sense rays which man cannot. 



Now, it is probably from such evidence as this that one biologist, at 

 least, draws the conclusion that just as there are undoubtedly thousands 

 of colors which no human eye can see, and thousands of sounds no 

 human ear can hear, so there must be thousands of factors in every 

 explanation which the human mind cannot grasp. This being true, it 

 follows that, if we can find any explanation which is plausible, and which 

 fits in with every nook and crevice of our mind, we know that such a 

 theory is not likely to be true, because there are thousands of points 

 that we must necessarily have neglected to consider due to our sheer 

 intellectual inability. Thus even the most plausible arguments are 

 vitiated. 



SUMMARY 



We have presented practically all of the important arguments for 

 and against evolution itself and the various theories which attempt to 

 account for it, because it is just as essential for a well-educated man to 

 know the opposing arguments in any given case as it is for him to know 

 the supporting ones. The theories which the student is to accept are 

 those which he finds sufficient evidence for in his work throughout his 

 laboratory course. 



Regardless of what one may believe that the evidence has brought 

 forth, all biological workers must accept evolution as a scientific- 

 hypothesis, though this does not mean that they must accept any of the 

 theories propounded to account for it. The above statement is true, 

 because there is much more evidence to show that an evolution has 

 taken place than there is to show how and why it took place. 



Then, too, the student must note the difference between the cause 



