Decembee llj 1914] 



SCIENCE 



839 



stances under which the work has heretofore 

 made progress. 



It is the examination of these things which 

 gives rise to such optimism, and especially of 

 those of them which belong to the last few 

 years. We shall not have time to take up 

 these matters in detail so as to examine the 

 events one by one; we can only indicate their 

 general characteristics, leaving it to the reader 

 to supply the concrete individual instances. 



Let us ask : What is the leading character- 

 istic, in the infancy of their development, of 

 those processes and results of thought which 

 have most profoundly influenced human 

 progress ? 



To attempt a fuU discussion of this prob- 

 lem would carry us too far aside. But a par- 

 tial answer lies close at hand. Great steps 

 forward have usually been taken in a way 

 which was not expected and in a field of men- 

 tal activity where the processes and results of 

 thought had assumed an apparently fixed 

 form. In such a region there had been for a 

 time a seething of thought with frequent 

 eruption of new theory; but at last everything 

 had come to a state of quiescence. Appar- 

 ently, nothing more was to be expected from 

 that quarter. But the appearance was false; 

 a fresh development came with astonishing 

 swiftness. 



Often at a moment when least expected new 

 and vital discoveries are made. Thought is 

 ruthlessly jostled out of the rut into which it 

 has fallen. A state of uncertainty and uneasi- 

 ness ensues. Eestlessly the mind seeks new 

 verities to which to fix itself. There is a gen- 

 eral shaking up of its content of thought. 

 The old bottles are not strong enough for the 

 new wine of new truth and are burst 

 asunder. This quickening of thought, this ex- 

 pansion into larger conception, this is the 

 leading characteristic of fundamental ad- 

 vances in human thinking. 



This which I have just described is to my 

 mind precisely the leading characteristic of 

 several important theories of modern science. 

 There has been a ruthless shaking up of the 

 whole substructure; uncertainty, and even 

 uneasiness, have arisen in many quarters; in 



some fields there is no longer any one who be- 

 lieves that he knows what should be expected. 

 An eminent scientist who, a few years ago, 

 was authority for the statement that the fu- 

 ture advancement of physics was to be looked 

 for in the fifth decimal place is now advising 

 younger men to try all sorts of " fool experi- 

 ments." This is an indication of the spirit 

 of the times. We find indeed that our power 

 over nature is increasing and that we can 

 make better predictions than ever before; but 

 we no longer have the faith which we one© 

 had in our theoretical explanations. 



In recent years one surprise after another 

 has come with such rapidity that we no longer 

 know what it is to be orthodox in scientific 

 theory. 



A new liberty — some will say, a new li- 

 cense — in theorizing has sprung up every- 

 where. The boldness of some of the new hy- 

 potheses is amazing, even disconcerting. If 

 ever they come into a general acceptance they 

 will give rise to an expansive development of 

 the human mind in virtue of our attempt to 

 understand the philosophic significance of the 

 new movements. They will require revision 

 of our ways of thinking, and will thus mark 

 a new stage in human progress. 



An examination of the discoveries which 

 have given rise to this sort of thing will lead 

 to the observation that many of them were 

 made in such unexpected ways that one al- 

 most feels as if they came about by accident. 

 In fact there seems to be a certain element of 

 haphazard in all scientific discoveries. We 

 have not yet learned how to make a syste- 

 matic and all-embracing search through 

 fields of thought either old or new. Our best 

 discoveries are frequently made in territory 

 over which we have trodden many times be- 

 fore. 



What are we to conclude from the fact that 

 our particular discoveries are so often hit 

 upon almost by chance and that we have 

 looked about so nearly at random and have 

 found such things? Let us answer by rais- 

 ing another question. Suppose that it had 

 been true twenty years ago that only a iew 

 fundamental facts yet remained to be discov- 



