206 PHYSICAL INVESTIGATION. [PART I. 



stand-point of the inquirer. It has been connected with 

 the theories on the origin of man, and the ape has been con- 

 sidered as the ancestor of man, which is the doctrine of 

 those who assume a development of animal species : it may 

 be that this transformation was limited to periods of great 

 geological changes, or that it was slowly progressive in the 

 course of time by continuous accommodation to external cir- 

 cumstances. 1 



Although one would not feel inclined to attach much value to 

 this theory in preference to that of the permanence of species, 

 it still appears important, from the analogy in which it stands to 

 a scientific theory of nature and human life. The gradual de- 

 velopment of the earth, and of higher forms from lower forms, 

 apparently without any manifestation of new creative power, 

 appears to force upon us that view of the origin of man, whose 

 history seems to show that the higher forms and the develop- 

 ment of external and internal life have proceeded from lower 

 forms, and which in course of time they maybe destined to super- 

 sede. Certain as it is that man has somewhere, and at some 

 period, appeared on this earth, it is equally certain that all 

 scientific analogies tend to show that he originated in a natural 

 way. It must, however, as candidly be admitted, that all analo- 

 gies indicating the transformation of the ape into a man are as 

 yet wanting to experimental science ; nor can we at present 

 scientifically render an account of the natural origin of man, 

 though science is justified in assuming it. But is the investi- 

 gator bound to establish theories in the absence of facts ? 

 Certainly not ; the love of truth, on the contrary, forbids it. 

 It is certainly very disagreeable to many to be bound to con- 

 fess that their wisdom is at an end ; but logic, and a real sci- 

 entific interest, require such a confession where facts are 

 wanting. If a theory can only be supported by a general ana- 

 logy and not by definite grounds, whilst there is opposed to it 

 a wide field of conflicting possibilities, its foundation is weak 

 indeed, and there remains in its favour but a scanty probability 

 that it may be as we are inclined to expect. 



1 Lamarck and his followers. I. Geoffrey St. Hilaire. 



