INSTINCT AND FINAL TENDENCY. 17 



It is obvious that the influence of "purpose," or a 

 final tendency, is met with everywhere in the universe. 

 The recognition of this truth is forcibly brought home 

 to us by the study of the laws of inorganic matter 

 in the wonderful cycle of carbon in the realm of nature, 

 the numeric proportions according to which atoms com- 

 bine and separate, the peculiar quality of water in 

 reaching its maximum density at 4 C. It is clearly 

 demonstrated by the laws of organic life in general, 

 and especially by the study of the human body, its 

 organs and functions, the eye, the heart, the circulation 

 of the blood, the activity of brain and nerves. But 

 nowhere is the recognition of final tendency demanded 

 more emphatically than in the explanation of the act- 

 ivity of animals which originates in their instinctive 

 faculties. Indeed, we meet with so many actions ap- 

 propriate to specific ends that, if anywhere in nature, 

 then surely in the domain of instinct, "final tendency' ' 

 holds the sceptre of sovereignty. 



Countless illustrations offered by natural history 

 show that the tendency, which is characteristic of all 

 instinctive activity, refers to the preservation of the 

 individual animal and of its distinctive species. Con- 

 sequently, there are three principal groups of instinc- 

 tive actions: those which refer to the nutrition of the 

 individual, those which tend to its defence, and 

 those which are directed toward the propagation 

 of the species. As it is impossible to investigate 

 every instinctive action in detail, we shall con- 

 fine our study to these three groups, and we shall 

 find abundant evidence to prove that "final tendency" 

 is an essential constituent of every activity that is 

 acknowledged to belong to the realm of instinct. 



