DR. DRAPER'S LECTURE ON EVOLUTION. 179 



considerations. These were now to be replaced by others of a more 

 definite and solid kind, derived from physical science. 



The starting-point of Christendom in the theory of evolution, for 

 the Mohammedans had now ceased to philosophize, was the publica- 

 tion by Copernicus of the book " De Revolutionibus Orbium Celes- 

 tium." In this the Pythagorean view of the emplacement of the solar 

 system was revived. The way for this restoration had been prepared 

 by such books as that of Cusa " On Learned Ignorance." He conceived 

 of -the universe as a vast organism, the life of which is the breath of 

 God, and which has neither centre nor circumference, but is infinite 

 as its maker. Such views were largely prevalent in Italy, at that 

 time the focus of infidelity, and there Copernicus had been. His work 

 was followed by Kepler's great discovery of the three laws that bear 

 his name. 



After the invention of printing, the "Index Expurgatorius " of pro- 

 hibited books had become essentially necessary to the religious Reign 

 of Terror, and for the stifling of the intellectual development of man. 

 The Papal Government, accordingly, established the Congregation of 

 that Index. 



It was very plain that the tendency of Kepler's discoveries was 

 to confirm the dominating influence of law in the solar system, as well 

 as to destroy geocentric and anthropocentric theories. It was, there- 

 fore, adverse to the Italian theological views, and to the current reli- 

 gious practices. Kepler had published an epitome of the Copernican 

 theory. This, as also the book itself of Copernicus, was placed in 

 the Index, and forbidden to be read. 



The Reformation came. It did not much change the matter. It 

 insisted on the Mosaic views, and would tolerate no natural science 

 that did not accord with them. Nevertheless, under the shadow of 

 the political power it shortly gathered, Newton's " Principia " was 

 safely published. The two great powers into which Christendom 

 was divided held each other in check. The sectarian divisions fast 

 springing up in Protestantism found occupation in their contentions 

 with each other. The bearing which Newton's book had upon those 

 already condemned consisted chiefly in this it gave indisputable 

 reasons that Kepler's laws are a mathematical necessity. For the 

 finger of Providence it substituted mechanical force. And thus the 

 Reign of Law, that great essential to the theory of evolution, was 

 solidly established. 



But not alone did the discoveries of physical astronomy lead to 

 these views. If the heavens were observed, the earth, also, was exam- 

 ined. There could no longer be any doubt that fossil remains were 

 the relics of beings that were once alive, as Xenophanes in the old 

 times, and Da Vinci and Palissy more recently, had affirmed not 

 mere hisus naturce ; that the earth's strata were not all of the same 

 age ; that in the oldest no fossils could be found ; that there had been 



