Febbuabt 21, 1913] 



SCIENCE 



279 



man's ability to discover and prove any- 

 thing about tlie reality of the world in 

 which he lives, or to apprehend with as- 

 surance of conviction what is now actually 

 taking place within or without, or what has 

 actually taken place in the past, we press 

 our scepticism and its resulting agnosticism 

 far beyond the limits warranted by a 

 proper understanding of the Protagorean 

 maxim. Man is indeed the measure of all 

 things, i. e., so far as things really exist 

 for him or actually happen in the real 

 world which environs his existence. 



So, then, he who takes his attitude to- 

 ward his own science, or toward the prac- 

 tical life, from that study of man in which 

 psychology and anthropology may cheer- 

 fully concur, will undoubtedly hold to a 

 certain theory of the relativity of all 

 knowledge. This theory will lead him to 

 say: There are a few things of which I 

 have perfectly certain and absolutely sure 

 knowledge. There are some more — per- 

 haps, many more — of which I am reason- 

 ably sure; and the surer, the more I grow 

 in knowledge. There are yet more of 

 which I am in doubt,, and about which I 

 am holding my mind in suspense and open 

 to the conviction which follows upon trust- 

 worthy and sufficient evidence. But the 

 things I do not know are like a vast and 

 limitless sea — to borrow an illustration 

 from the philosophy of Kant — on the bosom 

 of which lies my little island of knowledge 

 and opinion. How far future explorers in 

 all branches of science may sail that bound- 

 less ocean, or what other islands they may 

 discover or treasures bring up from its 

 depths, I am not going dogmatically to 

 pronounce. That would be to assume more, 

 in view of our present relations to the past 

 and the future of science, than any one is 

 justified in assuming. Besides as a stu- 

 dent of man from the anthropological point 



of view, I am taught to be cautiously ag- 

 nostic in this regard. 



But when any one says of himself, I 

 know absolutely nothing about myself, or 

 about things, or about the transactions be- 

 tween myself and things, or among things, 

 which I am confident have a corresponding 

 reality, he appears more modest with refer- 

 ence to his own powers than the doctrine 

 of the relativity of knowledge requires that 

 he should be. And when he goes on to 

 say, Tou, too, know nothing, and can know 

 nothing as to what is real and actual, he is 

 not altogether polite, not to say flattering, 

 toward a fellow aspirant for knowledge. 

 But when he proceeds with the declara- 

 tion : Neither I, nor you, nor anybody, 

 really knows anything, or ever can know 

 anything, about the real world and about 

 the events assumed actually to occur in 

 this world, his agnosticism has indeed 

 taken a suicidal turn. For, surely such 

 an agnostic knows that he does not know, 

 and yet somehow exists in a world about 

 which he and all others are in this state of 

 perpetual and incurable ignorance; and 

 this would seem to imply that I and others 

 without number, in the most important 

 respects like him, do also exist in an un- 

 knowable but undoubtedly actually exist- 

 ent world. It seems then that the com- 

 plete agnostic is the man who is very sure 

 that he can vindicate his agnosticism by 

 appeal to some actual, objective standard 

 of judgment which he and others possess 

 in common. That is to say, while arguing 

 from his doctrine that man is the measure 

 of all things to the conclusion that no 

 knowledge is possible, he involves the other 

 very important conclusion or assumption 

 that the world is full of actually existent 

 rational beings, besides and outside of 

 himself. 



The importance of considerations like 

 those just announced is greatly increased 



