196 NATURE AND MAN. 



correctness of his method, the geologist is almost entirely destitute 

 of any such means of verification. For the value of any prediction 

 that he may hazard — as in regard to the existence or non-existence 

 of coal in any given area — depends not only upon the truth of the 

 general doctrines of geology in regard to the succession of stratified 

 deposits, but still more upon the detailed knowledge which he may 

 have acquired of the distribution of those deposits in the particular 

 locality. Hence no reasonably-judging man would discredit either 

 the general doctrines or the methods of geology, because the pre- 

 diction proves untrue in such a case as that now about to be 

 brought in this neighbourhood to the trial of experience. 



We have thus considered man's function as the scientific in- 

 terpreter of Nature in two departments of natural knowledge ; 

 one of which affords an example of the strictest, and the other 

 of the freest method, which man can employ in constructing his 

 intellectual representation of the universe. And as it would be 

 found that in the study of all other departments the same methods 

 are used, either separately or in combination, we may pass at once 

 to another part of our inquiry. 



The whole fabric of geometry rests upon certain axioms which 

 every one accepts as true, but of which it is necessary that the 

 truth should be assumed, because they are incapable of demon- 

 stration. So, too, the deliverances of our "common sense" derive 

 their trustworthiness from what we consider the " self-evidence " 

 of the propositions affirmed. There are, then, certain primary 

 beliefs, which constitute the groundwork of all scientific reasoning ; 

 and we have next to inquire into their origin. 



This inquiry brings us face to face with one of the great 

 philosophical problems of our day, which has been discussed by 

 logicians and metaphysicans of the very highest ability as leaders 

 of opposing schools, with the one result of showing how much can 

 be said on each side. By the intuitionalists, it is asserted that the 

 tendency to form these primary beliefs is inborn in man, an original 

 part of his mental organization ; so that they grow up spontaneously 

 in his mind as its faculties are gradually unfolded and developed, 

 requiring no other experience for their genesis, than that which 

 suffices to call these faculties into exercise. But by the advocates 



