72 THE DESCENT OF MAN. Part I. 



its intellectual powers had become as well developed, or 

 nearly as well developed, as in man. For, firstly, the 

 social instincts lead an animal to take pleasure in 

 the society of its fellows, to feel a certain amount of 

 sympathy with them, and to perform various services 

 for them. The services may be of a definite and evi- 

 dently instinctive nature ; or there may be only a wish 

 and readiness, as with most of the higher social animals, 

 to aid their fellows in certain general ways. But these 

 feelings and services are by no means extended to all 

 the individuals of the same species, only to those of 

 the same association. Secondly, as soon as the mental 

 faculties had become highly developed, images of all 

 past actions and motives would be incessantly passing 

 through the brain of each individual ; and that feeling 

 of dissatisfaction which invariably results, as we shall 

 hereafter see, from any unsatisfied instinct, would arise, 

 as often as it was perceived that the enduring and 

 always present social instinct had yielded to some other 

 instinct, at the time stronger, but neither enduring in 

 its nature, nor leaving behind it a very vivid impres- 

 sion. It is clear that many instinctive desires, such as 

 that of hunger, are in their nature of short duration ; 

 and after being satisfied are not readily or vividly re- 

 called. Thirdly, after the power of language had been 

 acquired and the wishes of the members of the same 

 community could be distinctly expressed, the common 

 opinion how each member ought to act for the public 

 good, would naturally become to a large extent the guide 

 to action. But the social instincts would still give the 

 impulse to act for the good of the community, this im- 

 pulse being strengthened, directed, and sometimes even 

 deflected by public opinion, the power of which rests, as 

 we shall presently see, on instinctive sympathy. Lastly, 

 habit in the individual would ultimately play a very 



