132 DISCOVERY CH. 



modern spirit. He did, however, make better use of 

 the experimental method than any natural philosopher 

 who preceded him, and his work did much to break down 

 the barrier raised by traditional belief against indepen- 

 dent investigation. 



In the discovery of secrets, and in the investigation of the 

 hidden causes of things, clear proofs are afforded by trustworthy 

 experiments rather than by probable guesses and opinions of 

 ordinary professors and philosophers . . . To you alone, honest 

 and true men of science, who seek knowledge, not from books 

 only, but also from things themselves, do I address these magnetic 

 principles and this new sort of philosophy. If any disagree 

 with my opinion, let them at least take note of the experiments 

 and discoveries which have been worked out and demonstrated 

 by me, with many pains and vigils and expenses. Let them 

 rejoice in these, and employ them to better use if they are able. 

 W . Gilbert. 



The ancients used only two methods of investigation 

 the philosophical and the mathematical ; the third 

 method, by experiment, was put into deliberate practice 

 by Palissy, Gilbert and Galileo. By offering experi- 

 mental evidence against what was believed to be the 

 teachings of Aristotle, Galileo established the modern 

 experimental method of inquiry in Nature. The 

 authority of Aristotle as the arch-priest of natural 

 science had been questioned before the time of Galileo, 

 but no attempt had been made to confound it with truths 

 secured by direct appeal to Nature. The high regard in 

 which Galileo held the facts obtained by experiment, in 

 comparison with the conclusions of peripatetic philo- 

 sophy, is reflected in a letter written by him in 1615 : 



I would entreat these wise and prudent fathers to consider 

 diligently the difference between opinionative and demonstrative 

 doctrines, to the end that they may assure themselves that it 

 is not in the power of professors of demonstrative sciences to 

 change their opinions at pleasure. Galileo* 



