Descent of Man, and Selection in Relation to Sex, v.2

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390 GENERAL SUMMARY PART II. heart) imperfectly developed. This animal seems to have been more like the larvro of our existillg marine Ascidians than any other known form. The greatest difficulty which presents itself, when we are driven to the above conclusion on the origin of man, is the high standard of intellectual power and of moral disposition which he has attained. But every one who admits the general principle of evolution, must see that the mental powers of the higher animals, which arc the same in kind with those of mankind, though so different in degree, are capable of advancement. Thus the interval between the mental powers of one of the higher apes and of a fish, or between those of an ant and scale-insect, is immense. 'fhe develop­ment of these powers in animals does not offer any special difficulty; for with our domesticated animals, tho mental faculties are certainly variable, and the variations are inherited. No one doubts that these faculties are of the utmost importance to animals in a state of nature. Therefore the conditions are favour­able for their development through natural selection. The same conclusion may be extended to man; the intellect must have been all-important to him, even at a very remote period, enabling him to use language, to invent and make weapons, tools, traps, &c.; bv which means, in combination with his social habit~, he long ago became the most dominant of all living creatures. A great stride in the development of the intellect will have followed, as soon as, through a previous consi­Jerable advance, the half-art and half-instinct of lan­guage came into use; for the continued use of language will have reacted on tho brain, and produced an in­herited effect; and this again will have reacted on the CIIAI'. XXI. AND CONCLUDING REMARKS. 391 improvement of language. 'l'ho large size of the .brain. in man, in comparison with that of the lower ammals, relatively to the ~:;ize of their bodies, may be attributed in chief part, as Mr. Chauncey Wright has \Yell re­marked/ to the early use of some simple form of language,-that wonderful engine which affixes signs to all sorts of objects and qualities, and excites trains ·of thouo-ht which would never arise from the mere im- b pression of the senses, and if they did arise could not be followed out. 'fhe higher intellectual powers of man, such as those of ratiocination, abstraction, self­~ onsciousness, &c., will have followed from the con­tinued improvement of other mental faculties; but without considerable culture of the mind, both in the race and in the individual, it is doubtful whether these high powers would be exercised, and thus fully attained. The development of the moral qualities is a more interesting and difficult problem. Their foundation lies in the social instincts, including in this term the family ties. These instincts are of a highly complex nature, and in tho case of the lower animals give :apecial tendencies towards certain definite actions; but the more important elements for us are love, and the ·distinct emotion of sympathy. Animals endowed with the social instincts take pleasure in eaeh other's com­pany, warn each other of danger, defend and aid each ()ther in many ways. These instincts are not extended to all the individuals of the species, but only to those .of the same community. As they are highly beneficial to the species, they have in all probability been acquired through natural selection. A moral being is one who is capable of comparing I On the "Limits of Natural Selection," in the 'North American Review,' Oct. 1870, p. 29.5.