EVOLUTION OF THE HUMAN SPECIES 151 



territory of complex human life and of manifold human 

 relations. Without prolonged exercise in scientific 

 methods, it is impossible to view our own kind imper- 

 sonally, as we do the creatures of lower nature. Further- 

 more it seems to many that an analysis of human life 

 and biological history, even if it is possible, must alter 

 or degrade mankind in some degree; this is no more 

 true than that a knowledge of the principles of engineer- 

 ing according to which the Brooklyn Bridge has been 

 constructed renders that structure any different or 

 unsafe for travel. Man remains man, whether we are 

 in utter ignorance of his mode of origin, or whether we 

 know all about his ancestry and about the factors that 

 have made him human. It is because our species 

 appears to occupy a superior and isolated position above 

 the rest of nature that the mind seems reluctant to 

 follow the guidance of science when it conducts its 

 investigations into the history of seemingly privileged 

 human nature. And it is feared also, that if evolution 

 is proven for man as well as for all other kinds of ani- 

 mals, our cherished ideas and our outlook upon many 

 departments of human life must be profoundly affected. 

 This may be so, but science endeavors only to find out 

 the truth ; it cannot alter truth, nor does it seek to do 

 so. We might well wish that the world were different 

 in many respects and that we were free from the control 

 of many natural laws besides that of evolution, but if 

 the real is what it is, then our duty is plain before us ; 

 as we think more widely and deeply on the basis of 

 ripened experience, it becomes ever clearer that a knowl- 

 edge of human history gives the only sure guidance for 

 human life. 



