12 INTRODUCTION. 



that Darwin himself, in his famous book on the " Descent 

 of Man," did not begin, as might be expected, with the 

 comparison of anatomical or physiological observations, but 

 with a digression upon the gradual development of intel- 

 lectual powers in animals ; he well understood that if he 

 were to succeed in proving the animal descent of man, or 

 even in showing it to be possible, the objection would still 

 remain that man, so far as his mental faculties were con- 

 cerned, was nevertheless entirely and essentially different 

 from the rest of nature. And, although the great naturalist 

 had at his command comparatively small and poor materials 

 (in reality they are far more numerous and more con- 

 vincing), it was yet not difficult for him to find and point 

 out the rudiments, the roots, in animals of nearly every 

 intellectual and moral capacity found in man. For the rest, 

 this digression, like everything written by Darwin, is ad- 

 mirable, rich in facts and in striking deductions and obser- 

 vations, although Darwin here, as in his other writings, 

 uses always the mischievous term " instinct ; " this word 

 leaves room for so much misapprehension, that it should be 

 entirely avoided in scientific books, for, as Dr. Weinland 

 well points out, it is nothing but a lazy way of escaping from 

 the laborious study of animal intelligence. 



" It is as though there were some witchcraft in the word 

 'instinct,'" says Umbreit, in his "Science of Psychology" 

 (1831); "for with the phrase 'It is instinct,' all search 

 after the manifestations of the intelligent life [of animals] 

 is stopped as if by an anathema." 



" The distinction between intelligence and instinct," says 

 J. Franklin, " is now given up by all schools which have 

 examined facts. There is intelligence in animals and 

 instinct in man." 



" Instinct," says Dr. F. C. Noll, in an admirable treatise 

 on the manifestation of so-called instinct (Frankfort, 1876), 

 " is merely an empty word, a veil for our ignorance or 

 indolence." 



Darwin does not, of course, use the word instinct in the 

 old sense of an inexplicable and unchangeable impulse, 

 springing from an unknown source ; he uses it to describe 

 an inherited influence or tendency, originally acquired 

 through adaptation or natui'al and sexual selection, and 

 habits or capabilities of thought transmitted from generation 



