534 HISTORY OF GEOLOGY. 



to notice the perceptive and active faculties of 

 man; it appeared that there was a ready passage 

 from physiology to psychology, from physics to 

 metaphysics. In the class of sciences now under 

 notice, we are, at a different point, carried from the 

 world of matter to the world of thought and feel- 

 ing, from things to men. For, as we have already 

 said, the science of the causes of change includes 

 the productions of man as well as of nature. The 

 history of the earth, and the history of the earth's 

 inhabitants, as collected from phenomena, are go- 

 verned by the same principles. Thus the portions 

 of knowledge which seek to travel back towards the 

 origin, whether of inert things or of the works of 

 man, resemble each other. Both of them treat of 

 events as connected by the thread of time and 

 causation. In both we endeavour to learn accurately 

 what the present is, and hence what the past has 

 been. Both are historical sciences in the same 

 sense. 



It must be recollected that I am now speaking 

 of history as setiological ; as it investigates causes, 

 and as it does this in a scientific, that is, in a 

 rigorous and systematic, manner. And I may ob- 

 serve here, though I cannot now dwell on the sub- 

 ject, that all setiological sciences will consist of 

 three portions ; the Description of the facts and 

 phenomena ; the general Theory of the causes of 

 change appropriate to the case ; and the Applica- 

 tion of the theory to the facts. Thus, taking Geology 



