132 Science Religion and Reality 



was the Galenic physiological system finally sent to limbo. We 

 hear of it no more. 



It is remarkable that all these biological advances, and even 

 the introduction and revelations of the microscope, left the theo- 

 logical world almost unmoved. Even the idea of the automatism 

 of animal movements and reactions developed by Descartes, and 

 further extended later in the century by Borelli and his school, had 

 little or no effect on the position. It was much the same with the 

 work of the chemists. Far otherwise was it with the physical and 

 astronomical discoveries. From the first these attracted theo- 

 logical attention, and throughout the century there was great 

 activity in these departments. 



From the multitude of workers on these subjects we can but 

 select types. Those we choose are men whose investigations 

 most directly influenced the relation of scientific to religious thought. 

 In the first half of the century Galileo and Kepler are the main 

 exponents of natural law. Descartes takes his place here as the 

 first since antiquity who sought to explain the phenomenal universe 

 on a unitary basis. In the second half of the period comes the 

 mighty figure of Newton, whose researches ushered in that phase 

 in our story in which we live to-day. 



Galileo Galilei (1564-1642} lived a long life of almost un- 

 paralleled intellectual activity. Many of the products of his 

 genius were of immediate practical application, many more in- 

 volved profound modification of the current scientific opinions, 

 yet others struck at the very basis of the general beliefs of the day. 

 It is with the last class alone that we are here concerned. 



The early training of Galileo had been along strictly scholastic 

 and Aristotelian lines, as is shown by his lecture note-books written 

 in or before 1^84. Soon after this date he seems to have begun 

 a systematic experimental investigation of the mechanical doctrines 

 of Aristotle. There resulted the " Sermones de Motu Gravium^'' 

 which was circulating in manuscript in 1590 though it did not 

 appear in print until 250 years later. The work contains a number 

 of objections to Aristotelian teaching, together with a record of 

 experiments on the rate of acceleration of falling bodies. These 

 doctrines were announced from his professorial chair and in the 

 following year were demonstrated from the leaning tower of Pisa. 

 By that famous experiment he showed in the most public manner 

 the error of the Aristotelian view that treated the rate of fall as a 



