122 PHYSICAL BASIS OF CIVILIZATION 



though not as easily possible, to make experiments 

 confirming the situation and conduct of the upright 

 brute actors as depicted in the five paragraphs 

 mentioned. And are the greater difficulties in- 

 volved reasons from which to argue against the 

 acceptance of this explanation, when only accord, 

 and no discord, exists between the known and 

 ascertainable facts and the assumed explanation? 

 When this is the only possible rational explanation, 

 and when the conditions thus explained are in 

 accord with the totality of average, normal, human 

 experience, and not in discord with any part of it ? 



