358 POPULAR SCIENCE MONTHLY 



rearrangement of our preconceptions is to ignore them altogether, or 

 to abuse those who bear witness for them. 



You doubtless wish examples of this process of truth's growth, and 

 the onlv trouble is their superabundance. The simplest case of new 

 truth is jf course the mere numerical addition of new kinds of fact, 

 or of new facts of old kinds, to our experience — an addition that in- 

 volves no alteration in the old beliefs. Day follows day, and its con- 

 tents are simply added. The new contents themselves are not true, 

 they simply come and are. Truth is what we say about them, and 

 when we say that they have come, truth is satisfied by the plain additive 

 formula. 



But often the day's contents oblige a rearrangement. If I should 

 now ntter piercing shrieks and act like a maniac on this platform, it 

 would make many of you revise your ideas as to the probable worth of 

 my philosophy. ' Eadium ' came the other day as part of the day's 

 content, and seemed for a moment to contradict our ideas of the whole 

 order of nature, that order having come to be identified with what is 

 called the conservation of energy. The mere sight of radium pay- 

 ing heat away indefinitely out of its own pocket, seemed to violate that 

 conservation. What to think? If the radiations from it were nothing 

 but an escape of unsuspected ' potential ' energy, preexistent inside 

 the atoms, the principle of conservation would be saved. The dis- 

 covery of ' helium ' as the radiation's outcome, opened a way to this 

 belief. So Ramsay's view is generally held to be true, because, 

 although it extends our old ideas of energy, it causes a minimum of 

 alteration in their nature. 



I need not multiply instances. A new opinion counts as ' true ' 

 just in proportion as it gratifies the individual's desire to assimilate the 

 novel in his experience to his beliefs-in-stock. It must both lean on 

 old truth and grasp new fact; and its success (as I said a moment ago), 

 in doing this, is a matter for the individual's appreciation. When 

 old truth grows, then, by new truth's addition, it is for subjective 

 reasons. We are in the process and obey the reasons. That new idea 

 is truest which performs most felicitously its function of satisfying our 

 double urgency. It makes itself true, gets itself classed as true, by the 

 way it works; grafting itself then upon the ancient body of truth, 

 which grows, thus, much as a tree grows by the activity of a new layer 

 of cambium. 



Now Dewey and Schiller proceed to generalize this observation and 

 to apply it to the most ancient parts of truth. They also once were 

 plastic. They also were called true for human reasons. They also 

 mediated between still earlier truths and what in those days were novel 

 observations. Purely objective truth, truth in whose establishment 

 the function of giving human satisfaction in marrying one part of 

 experience with another played no part whatever, is nowhere to be 



