iv PREFACE BY THE AUTHOR. 



rious examination. Such, at least, is the principal pur- 

 pose of this book. 



It has another, also. The evident disposition of the 

 present day is to repose infinite hopes on the natural 

 sciences, and to expect unlimited benefits from them. 

 I certainly shall not view this inclination as an illu- 

 sion, and this volume sufficiently attests the high value 

 I set upon all that can encourage and foster such feel- 

 ings. But precisely because I am not suspected of en- 

 mity to those sciences, it has seemed to me the more 

 necessary to indicate a fatal mistake accompanying 

 those commendable sentiments; I mean the mistake 

 of those who, after loudly praising the excellence of 

 science, denounce the weakness and deny the author- 

 ity of metaphysics. 



Now, my reader will come upon more than one 

 page manifestly inspired by the conviction that science, 

 properly so called, does not satiate the mind eager to 

 know and to understand, and that therefore metaphys- 

 ics holds a large and an authorized place in the activity 

 of human thought. While I have retouched every thing 

 in these essays which seemed to me, from an exclusively 

 scientific point of view, susceptible of a higher degree 

 of exactness and precision, I have, on the contrary, 

 preserved with jealous care the literal tenor of all the 

 passages expressly written under the influence of that 

 conviction. And I have done so, not because of any 

 peculiar value in those reflections, many of which are 

 nothing more than a very imperfect representation of 



