MAY AXD BRUTE. 3 



rooted prejudices regard in<; his own position in nature, and 

 his relations to the wider world of life ; while that which 

 remains a dim suspicion for the unthinking, becomes a vast 

 argument, fraught with the deepest consequences, for all 

 who are acquainted with the recent progress of anatomical 

 and physiological sciences," * 



The problem, then, which in this generation has for the first 

 time been presented to human thought, is the problem of how 

 this thought itself has come to be. A question of the deepest 

 importance to every system of philosophy has been raised by 

 the study of biology ; and it is the question whether the mind 

 of man is essentially the same as the mind of the lower 

 animals, or, having had, either wholly or in part, some other 

 mode of origin, is essentially distinct — differing not only in 

 degree but in kind from all other types of psychical being. 

 And forasmuch as upon his great and deeply interesting 

 question opinions are still much divided — even among those 

 most eminent in the walks of science who agree in accepting 

 the principles of evolution as applied to explain the mental 

 constitution of the lower animals, — it is evident that the 

 question is neither a superficial nor an easy one. I shall 

 however, endeavour to examine it with as little obscurity as 

 possible, and also, I need hardly say, with all the impartiality 

 of which I am capable, f 



It will be remembered that in the introductory chapter of 

 my previous work I have already briefly sketched the manner 

 in which I propose to treat this question. Here, therefore, it 

 is sufficient to remark that I began by assuming the truth of 

 the general theory of descent so far as the animal kingdom 



• Mans Place in A'ature, p. 59. 



t It is perhaps desirable to explain from the first that by the words " difTcrcnce 

 of kind," as used in the above paragraph and elsewhere throughout this treatise, 

 I mean difference of ori^n. This is the only real distinction that can be dr.i«n 

 between the terms " difference of kind " and " difference of degree ; " and I should 

 scarcely have dccmctl it worth while to give the definition, h.ad it not been for the 

 confused manner in which the terms are used by some writers — e.^. Professor 

 Sayce, who says, while speaking of the development of languages from a common 

 source, " differences of degree l>ccomc in time differences of kind " (/ntroJuclion 

 to (hi Science of Language, ii. 309). 



