INTRODUCTION. 11 



individual being lie cannot be fully understood. Anatomy and 

 physiology have therefore by themselves no claim to deter- 

 mine the nature of man; nor can they do so in combination 

 with psychology, which being chiefly founded on self-contem- 

 plation, carries us but a few steps beyond the individual man. 

 There is no doubt that the social life into which he enters, con- 

 tributes much towards teaching the individual what passes 

 within him, as in a mirror, and exhibits to him sensually what 

 he would never have been able to comprehend by mere self- 

 contemplation. Nevertheless, this enlarged field of observation 

 is still too confined to enable us to deduce from it alone the 

 notion of Man. 



In order to extend our horizon we must direct our atten- 

 tion to the history of a people, and from it to the whole 

 history of civilization. Yet even this basis is not sufficiently 

 comprehensive. We require, in order to have a just conception 

 of the nature of man, a knowledge of all mankind; but this 

 knowledge cannot be obtained nor even thought of, if it 

 is not preceded by defining the limits of mankind, and deter- 

 mining the question whether all men are of one species, or 

 if not, within what limits the notion of species is to be con- 

 fined. 



The question whether the individuals which we are accus- 

 tomed to call human beings, are all of one stock, or whether 

 there are ^between them permanent specific differences, is im- 

 portant to all sciences. Whether the knowledge of which man 

 is capable, is absolute for all thinking beings, or is only rela- 

 tive to his peculiar stand-point, still all his thinking and know- 

 ing is specifically human, and his only concern is that it should 

 be universally valid among human beings ; for every endeavour 

 in our researches to rise above the sphere in which nature has 

 confined us, resembles the attempt to fly with imaginary wings, 

 when it is inconvenient to put the legs in motion. All the 

 truths which are brought to light necessarily relate to the 

 nature of man, partly, since all knowledge comes of him, and 

 partly because all recognized truths lay claim to general assent, 

 requiring confirmation, not by individual and merely subjective, 

 but by universal human conceptions and notions. We may, 



