EXAMPLES OF THE FOUR METHODS. 475 



towards the sun. It was this which determined astronomers 

 to consider the law of gravitation as obtaining between 

 all bodies whatever, and therefore between all particles of 

 matter; their first tendency having been to regard it as a 

 force acting only between each planet or satellite and the 

 central body to whose system it belonged. Again, the 

 catastrophists, in geology, be their opinion right or wrong, 

 support it on the plea, that after the effect of all causes 

 now in operation has been allowed for, there remains in the 

 existing constitution of the earth a large residue of facts, 

 proving the existence at former periods either of other forces, 

 or of the same forces in a much greater degree of intensity. 

 To add one more example : those who assert, what no one 

 has shown any real ground for believing, that there is in 

 one human individual, one sex, or one race of mankind 

 over another, an inherent and inexplicable superiority in 

 mental faculties, could only substantiate their proposition by 

 subtracting from the differences of intellect which we in fact 

 see, all that can be traced by known laws either to the ascer- 

 tained differences of physical organization, or to the dif- 

 ferences which have existed in the outward circumstances in 

 which the subjects of the comparison have hitherto been 

 placed. What these causes might fail to account for, would 

 constitute a residual phenomenon, which and which alone 

 would be evidence of an ulterior original distinction, and 

 the measure of its amount. But the assertors of such sup- 

 posed differences have not provided themselves with these 

 necessary logical conditions of the establishment of their 

 doctrine. 



The spirit of the Method of Residues being, it is hoped, 

 sufficiently intelligible from these examples, and the other 

 three methods having already been so fully exemplified, we 

 may here close our exposition of the four methods, considered 

 as employed in the investigation of the simpler and more 

 elementary order of the combinations of phenomena. 



6. Dr. Whewell has expressed a very unfavourable 

 opinion of the utility of the Four Methods, as well as of the 



