PREFACE TO THE AMERICAN EDITION. 



THE present volume is the first of a series designed to un- 

 fold the principles of a new philosophy. It is divided into 

 two parts: the aim of the first being to determine the true 

 sphere of all rational investigation, and of the second, to 

 elucidate those fundamental and universal principles which 

 science has established within that sphere, and which are to 

 constitute the basis of the system. The scheme of truth de- 

 veloped in these First Principles is complete in itself, and 

 has its independent value; but it is designed by the 

 author to serve for guidance and verification in the con- 

 struction of the succeeding and larger portions of his philo- 

 sophic plan. 



Having presented in his introductory volume so much of 

 the general principles of Physics as is essential to the devel- 

 opment of his method, Mr. Spencer enters upon the subject 

 of Organic nature. The second work of the series is to be the 

 Principles of Biology a systematic statement of the facts 

 and laws which constitute the Science of Life. It is not to 

 be an encyclopedic and exhaustive treatise upon this vast 

 subject, but such a compendious presentation of its data and 

 general principles as shall interpret the method of 

 nature, afford a clear understanding of the questions in- 

 volved, and prepare for further inquiries. This work is 

 now published in quarterly numbers, of from 80 to 96 



pages. Four of these parts have already appeared, and some 



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