366 SPARKS FROM A GEOLOGIST'S HAMMER. 



as a body of knowledge. It is commonly regarded as the 

 most certain of all knowledge, and the safest foundation 

 for belief, expectation and action. Men stand firm on the 

 conclusions of science, however they falter on the isolated 

 propositions which science subsumes. They formulate 

 their creeds on the dicta of science, though they may pro- 

 fess to doubt or be ignorant in the presence of the naked 

 principles which authenticate the dicta of science. 



That science attains to valid knowledge cannot be ra- 

 tionally denied. Instead of denying, it is our purpose to 

 demonstrate that it is valid; and that it is valid because 

 certain underlying principles which science never men- 

 tions are the firm foundations on which it rests. 



I. All science begins in the assumed existence of a 

 real, thinking being. But what is the ground of the 

 assumption of our personal existence and personal identity 

 from moment to moment and from day to day? The 

 conviction is grounded in our inmost consciousness; we 

 are unable to resist it; but it is only a belief a valid 

 belief the ultimate elemental utterance of mind, speak- 

 ing with the authority of its very being. Nothing, of 

 course, can validate its utterance; but, if we choose to 

 admit a speculative doubt, we negative at once all possi- 

 bility of science and all possibility of a scientific basis 

 for anything. 



All trustworthiness of memory rests in the presuppo- 

 sition, not only that the representative faculty is a true 

 witness, but that we are the same being as yesterday. 

 The scientist records his notes after hours, days or weeks 

 have passed; and he builds most serious reasoning on the 

 assumption that it was he who made the observations 

 which he seems to reproduce. If he is mistaken in this, 



