2 28 THE POPULAR SCIENCE MONTHLY. 



No one has hitherto treated the subject from this point of view. 

 Yet from this point it presents itself to us as a living issue in fact, 

 as the most important of all living issues. 



A few years ago, it was the politic and therefore the proper course 

 to abstain from all allusion to this controversy, and to keep it as far 

 as possible in the background. The tranquillity of society depends so 

 much on the stability of its religious convictions, that no one can be 

 justified in wantonly disturbing them. But faith is in its nature 

 unchangeable, stationary ; Science is in its nature progressive ; and 

 eventually a divergence between them, impossible to conceal, must 

 take place. It then becomes the duty of those whose lives have made 

 them familiar with both modes of thought, to present modestly, but 

 firmly, their views ; to compare the antagonistic pretensions calmly, 

 impartially, philosophically. History shows that, if this be not done, 

 social misfortunes, disastrous and enduring, will ensue. When the 

 old mythological religion of Europe broke down under the weight of 

 its own inconsistencies, neither the Roman emperors nor the philoso- 

 phers of those times did any thing adequate for the guidance of pub- 

 lic opinion. They left religious affairs to take their chance, and ac- 

 cordingly those affairs fell into the hands of ignorant and infuriated 

 ecclesiastics, parasites, eunuchs, and slaves. 



The intellectual night which settled on Europe, in consequence of 

 that great neglect of duty, is passing away ; we live in the daybreak 

 of better things. Society is anxiously expecting light, to see in what 

 direction it is drifting. It plainly discerns that the track along which 

 the voyage of civilization has thus far been made, has been left ; and 

 that a new departure, on an unknown sea, has been taken. 



Though deeply impressed with such thoughts, I should not have 

 presumed to write this book, or to intrude on the public the ideas it 

 presents, had I not made the facts with which it deals a subject of 

 long and earnest meditation. And I have gathered a strong incentive 

 to undertake this duty from the circumstance that a " History of the 

 Intellectual Development of Europe," published by me several years 

 ago, which has passed through many editions in America, and has 

 been reprinted in numerous European languages, English, French, 

 German, Russian, Polish, Servian, etc., is everywhere received with 

 favor. 



In collecting and arranging the materials for the volumes I pub- 

 lished under the title of " A History of the American Civil War," a 

 work of very great labor, I had become accustomed to the comparison 

 of conflicting statements, the adjustment of conflicting claims. The 

 approval with which that book has been received by the American 

 public, a critical judge of the events considered, has inspired me with 

 additional confidence. I had also devoted much attention to the ex- 

 perimental investigation of natural phenomena, and had published 

 many well-known memoirs on such subjects. And perhaps no one can 



