308 



SCIENCE. 



[N. S. Vol. XIV. No. 348. 



though intimately related to, was more or 

 less opposed to the supernatural ; the latter 

 being, in fact, under the uncertain sway of, 

 and the former subject to the arbitrary 

 jurisdiction of, good and evil spirits. 



The second fact is that man thus early 

 devised for the investigation of this problem 

 three distinct methods, which have likewise 

 persisted with equal tenacity, though with 

 varying fortunes, down to the present day. 

 The first of these is what is known as the 

 a priori method. It reasons from subjective 

 postulates to objective results. It requires, 

 in its purity, neither observation nor ex- 

 periment on the external world. It often 

 goes so far, indeed, as to adopt conclusions 

 and leave the assignment of the reasons for 

 them to a subsequent study. The second 

 is known as the historico-critical method. 

 It depends, in its purity, on tradition, his- 

 tory, direct human testimony and verbal 

 congruity. It does not require an appeal 

 to Nature except as manifested in man. It 

 limits observation and experiment to human 

 affairs. The third is the method of science. 

 It begins, in its elements, with observation 

 and experiment. Its early applications 

 were limited mostly to material things. In 

 its subsequent expansion it has gained a 

 footing in nearly every field of thought. 

 Its prime characteristic is the insistence on 

 objective verification of its results. 



All these methods have been used more or 

 less by all thinking men. But for the pur- 

 poses of ready classification it may be said 

 that the first has been used chiefly by dog- 

 matists, including especially the foundersand 

 advocates of all fixed creeds from the athe- 

 istic and the pantheistic to the theistic and 

 the humanistic ; the second has been used 

 chiefly by humanists, including historians, 

 publicists, jurists and men of letters ; and 

 the third has been used chiefly by scientists, 

 including astronomers, mathematicians, 

 physicists, naturalists, and more recently 

 the group of investigators falling under the 



comprehensive head of anthropologists. 

 The first and third methods are frequently 

 found to be mutually antithetical, if not mu- 

 tually exclusive. The second occupies mid- 

 dle ground. Together they are here set 

 down in the order of their apparent early 

 development and in the order of their popu- 

 larly esteemed importance during all his- 

 toric time previous to, if not including, this 

 first year of the twentieth century. 



No summary view of the progress of 

 science, it seems to me, can be made intelli- 

 gible except by a clear realization of these 

 two facts, which may be briefly referred to 

 as man's conception of the universe and his 

 means of investigating it. "What, then, in 

 the light of these facts, has been the sequel ? 

 The full answer to this question is an old 

 and a long story, now a matter of minute 

 and exhaustive history as regards the past 

 twenty centuries. I have no desire to re- 

 call the dramatic events involved in the 

 rise of science from the Alexandrian epoch 

 to the present day. All these events are 

 trite enough to men of science. A mere 

 reference to them is a sufficient suggestion 

 of the existence of a family skeleton. But, 

 setting aside the human element as much 

 as possible, it may not be out of place or 

 time to state what general conclusions ap- 

 pear to stand out plainly in that sequel. 

 These are our tangible heritage and upon 

 them we should fix our attention. 



In the first place, the progress of science 

 has been steadily opposed to, and as stead- 

 ily opposed by, the adherents of man's 

 primitive concepts of the universe. The 

 domain of the natural has constantly 

 widened and the domain of the supernatu- 

 ral has constantly narrowed. So far, at 

 any rate, as evil spirits are concerned, they 

 have been completely cast out from the 

 realm of science. The arch fiend and the 

 lesser princes of darkness are no longer use- 

 ful even as an hj'pothesis. We have 

 reached — if I may again use the cautious 



