THE COURSE OF NATURE. 



483 



what this difference of view consists. I shall, 

 therefore, endeavor briefly to explain it. 



The theologian looks upon the doctrines he 

 has been taught as something the truth of which 

 is essential to the welfare of humanity, and, we 

 might almost say, to the supremacy of the Crea- 

 tor. He thus invests them with an attribute of 

 moral excellence, implied rather than expressed 

 in the term orthodoxy, and looks upon those who 

 attack them not simply as men who are mistaken, 

 but as men who are seeking to do a great injury 

 to the human race. Hence, the idea of weighing 

 the arguments on both sides, with entire indiffer- 

 ence to the result, is one which he cannot be ex- 

 pected to receive with favor, or even to readily 

 comprehend as received by others. His idea of 

 truth is symbolized in the pure marble statue, 

 which must be protected from contact with pro- 

 fane hands and whose value arises from its beauty 

 of form and the excellence of the ideas which 

 it embodies. He, therefore, looks upon those 

 who attack it with feelings not unlike those of 

 the keeper of the statue upon a chemist who 

 refuses to see anything in the statue except a 

 lump of carbonate of calcium of peculiar form, 

 and who wants to handle it, weigh it, determine 

 its specific gravity and its cohesive power, and 

 test its substance with acids. The corresponding 

 idea of the scientific investigator is symbolized 

 by the iron-clad turret, which cannot be accepted 

 until it has proved its invulnerability. Instead, 

 therefore, of being protected from violence, as if 

 it were a product of the fine arts, violence is in- 

 vited. Its weak points are sought out by eyes 

 intent on discovering them, and are exposed to 

 the fire of every logical weapon which can be 

 brought to bear upon them. A scientific theory 

 may thus be completely demolished. It may 

 prove so far from perfect that its author is glad 

 to withdraw it for repairs or reconstruction, or it 

 may be hammered into an entirely new shape. 

 But, however completely it may stand the fire, it 

 maintains its position as a scientific theory only 

 by being always in the field, ready to challenge 

 every new-comer and to meet the fire of every 

 fact which seems to militate against it. A 

 countless host of theories have thus been demol- 

 ished and forgotten with the advance of knowl- 

 edge ; but those which remain, having stood the 

 fire of generations, can show us a guarantee of 

 their truthfulness which would not be possible 

 under any other plan of dealing with them. 



As a consequence of this way of viewing the- 

 ories, the scientific man recognizes no such at- 

 tribute as orthodoxy in his doctrines. There is 



nothing at all which he says you must believe to 

 be true as a condition of scientific recognition. 

 There may, indeed, be many propositions to doubt 

 which would indicate extraordinary incredulity, 

 or downright folly, or even insanity ; and he 

 might, therefore, regard a skeptic as possessing 

 a pitiful feebleness of intellect, and, in conse- 

 quence, refuse to listen to him. But he would 

 refuse, not because the man differed from him in 

 opinion, but because he was not worth listening 

 to. Perhaps the point which I am striving to 

 make clear may be most readily grasped by the 

 reflection that science offers its highest rewards 

 to him who will overthrow and supplant its best- 

 established and most widely-received theories. 

 Thus, the names of the men who disproved the 

 theory of epicycles in astronomy and the doctrine 

 of phlogiston in chemistry occupy the most hon- 

 orable positions in the history of science. Of 

 course, no such thing as authority in science has 

 anything more than a provisional recognition. 

 If a man of good repute says that he has inves- 

 tigated a certain subject and reached a certain 

 result, the latter may be accepted on his authori- 

 ty, in the absence of other evidence. But this 

 gives no reason at all why any one else should 

 not reach a different result, and it would be no 

 argument at all to cite the mere authority of the 

 first against the second. In case of a discrepancy 

 of this kind, the whole question would have to 

 be investigated anew. Of course, the dictum, " It 

 is written," has no terror whatever for the inves- 

 tigator of Nature. He can recognize no authority 

 for any feature in the course of Nature except 

 Nature herself, as he sees her. 



These principles are of so much importance 

 in the philosophy of science that I may be par- 

 doned for viewing them in yet another light. 

 In reading those discussions with scientific men 

 on certain theories recently advanced by the more 

 advanced students of philosophic biology in which 

 the representatives of theology sometimes enter, 

 I have often noticed that, if the representative 

 of science propounds, discovers, or brings forward 

 any fact or principle which seems to tell against 

 his side of the question, the other calls it an " ad- 

 mission " or " concession ; " just as if his oppo- 

 nent had first selected his side for the love of it, 

 and was then unwilling to concede or admit any- 

 thing which might militate against it. Now, to go 

 into the philosophy of the subject a little deeper 

 than heretofore, allow me to say that the man of 

 science professes no ability to recognize truth at 

 sight, as he would recognize a house or an animal. 

 The question whether any given proposition is or 



