to make as little change as possible in ancient 

 conceptions. 



Luther, the greatest thought-stirrer of them all, 

 practically of the same generation with Copernicns, 

 Leonardo and Colnmbus, does not come in as a scien- 

 tific investigator, bnt as the great loosener of chains 

 which had so fettered the intellect of men that they 

 dared not think otherwise than as the authorities thought. 



Almost coeval with the advent of these intellects 

 was the invention of printing with movable type. 

 Gutenberg was born during the first decade of the 

 century, and his associates and others credited with 

 the invention not many years afterward. If we 

 accept the principle on which I am basing my argu- 

 ment, that we should assign the first place to the birth 

 of those psychic agencies which started men on new 

 lines of thought, then surely was the fifteenth the won- 

 derful century. 



Let us not forget that, in assigning the actors then 

 born to their places, we are not narrating history, but 

 studying a special phase of evolution. It matters not 

 for us that no university invited Leonardo to its halls, 

 and that his science was valued by his contemporaries 

 only as an adjunct to the art of engineering. The 

 great fact still is that he was the first of mankind to 

 propound laws of motion. It is not for anything in 

 Luther's doctrines that he finds a place in our scheme. 

 No matter for us whether they were sound or not. 

 What he did toward the evolution of the scientific 

 investigator was to show by his example that a man 

 might question the best-established and most venerable 

 authority and still live still preserve his intellectual 



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