August 30, 1901.] 



SCIENCE. 



309 



language of diplomacy — a satisfactory mo- 

 dus Vivendi if we have not attained perma- 

 nent peace in all our foreign relations. 

 Enlightened man has come to see that his 

 highest duty is to cooperate with Nature, 

 that he may expect to get on very well if 

 he heeds her advice, and that he may ex- 

 pect to fare very ill if he disregards it. 



Secondly, it appears to have been demon- 

 strated that neither the a priori method of 

 the dogmatists nor the historico-critical 

 method of the humanists is alone adequate 

 for the attainment of definite knowledge of 

 either the internal or the external world, or 

 of their relations to one another. In fact, 

 it has been shown over and over again that 

 man cannot trust his unaided senses even 

 in the investigation of the simplest and 

 most obvious material phenomiena. There 

 is an ever-present need of a correction for 

 personal equation. Left to himself, the a pri- 

 ori reasoner weaves from the tangled skein 

 of thought webs so well tied by logical knots 

 that there is no escape for the imprisoned 

 mind except by the rude process applied to 

 cobwebs. And in the serenity of his repose 

 behind the fortress of ' liberal culture, ' the 

 reactionary humanist will prepare apologies 

 for errors and patch up compromises be- 

 tween traditional beliefs and sound learn- 

 ing with such consummate literary skill 

 that even ' the good demon of doubt ' is al- 

 most persuaded that if knowledge did not 

 come to an end long ago it will soon reach 

 its limit. In short, we have learned, or ought 

 to have learned, from ample experience, 

 that in the search for definite, verifiable 

 knowledge we should beware of the investi- 

 gator whose equipment consists of a bundle 

 of traditions and dogmas along with formal 

 logic and a facile pen ; for we may be sure 

 that he will be more deeply concerned with 

 the question of the safety than with the 

 question of the soundness of scientific doc- 

 trines. 



Thirdly, it has been demonstrated equally 



clearly, and far more cogently, that the sort 

 of knowledge we call scientific, knowledge 

 which has in it the characteristics of im- 

 manence and permanence, is founded on 

 observation and experiment. The rise and 

 growth of every science illustrate this fact. 

 Even pure mathematics, commonly held to 

 be the a priori science par excellence, and 

 sometimes called ' the science of necessary 

 conclusions,' is no exception to the rule. 

 Those who would found mathematics on a 

 higher plane have apparentl}^ forgotten to 

 consider the contents of the mathematician's 

 waste-basket. The slow and painful steps 

 by which astronomy has grown out of as- 

 trology and chemistry out of alchemy ; and 

 the faltering, tedious, and generally hotly 

 contested, advances of geology and biology 

 have been rnade secure only by the re- 

 morseless disregard which observational 

 and experimental evidence has shown for 

 the foregone conclusions of the dogmatists 

 and the literary opinions of the humanists. 

 Thus it has been proved by the rough logic 

 of facts and events that the rude processes 

 of 'trial and error,' processes which many 

 philosophers and some men of science still 

 affect to despise, are the most effective 

 means yet devised by man for the discovery 

 of truth and for the eradication of error. 



These facts are so well known to most 

 of you, so much a matter of ingrained ex- 

 perience, that the categorical mention of 

 them here may seem like a rehearsal of 

 truisms. But it is one of the paradoxes of 

 human development that errors which have 

 been completely dislodged from the minds 

 of the few may still linger persistently in 

 the minds of the many, and that the mislead- 

 ing hypotheses and the dead theories of one 

 age may be resuscitated again and again in 

 succeeding ages. Thus, to cite one of the 

 simplest examples, it doubtless appeared 

 clear to the Alexandrian school of scientists 

 that the flat, four-cornered earth of con- 

 temporary myths would speedily give way 



