Maech 20, 1896.] 



SCIENCE. 



439 



apparatus of brain, nerve and muscle has not 

 been made ready for the combination which is 

 effected. As far as there are modifications in 

 the grouping, even these are very slight func- 

 tional variations from the uses already made of 

 the muscles involved. This point is no longer 

 subject to dispute ; for pathological cases show 

 that unless some adequate idea of a former 

 movement made by the same muscles, or by as- 

 sociation some other idea which stands for it, 

 can be brought up in mind the intelligence is 

 helpless. Not only can it not make new move- 

 ments; it can not even repeat old habitual 

 movements. So we may say that intelligent 

 adaptation does not create coordinations; it 

 only makes functional use of coordinations 

 which were alternatively present already in the 

 creature's equipment.* 



Interpreting this in terms of congenital vari- 

 ations, we may say that the variations which 

 the intelligence uses are alternative possibilities 

 of muscular movement. But these are exactly 

 the variations which instinct uses, except that 

 in instinct they are not alternative. That this 

 is so, indeed, lies at the basis of the claim that 

 instinct is inherited habit. The real difference 

 in the Variation involved in the two cases is in 

 the connection in the brain whereby in instinct 

 the muscular coordination is brought into play 

 directly by a sense stimulation; while in intelli- 

 gence it is brought into play indirectly, i. e., 

 through association of brain processes, but by 

 the same sense stimulation or a similar one. 

 Now this difference in the central brain connec- 

 tions is, I submit, not at all a great one rela- 

 tively speaking, and it might well be due to 

 spontaneous variations. The point of view 

 which holds that great co-adaptations of muscu- 

 latur are to be acquired all at once by the crea- 

 ture is quite mistaken. 



The same class of considerations refutes the 

 argument from 'selective value.' This argu- 

 ment holds that the instinct could not have 

 arisen by variations alone, with natural selec- 



* When we strain our muscles to accomplish a new 

 act of skill we are aiming to use the apparatus in 

 new ways by a selection from possible combinations; 

 and even when we learn to use disused muscles, as 

 those of the ear, we are only stirring up old connec- 

 tions. 



tion, since partial coordination tending in the 

 direction of the instinct would not have been 

 useful ; so the creatures with such partial coor- 

 dinations merely would have been killed off, 

 and the instinct could never have reached ma- 

 turity ; only variations which are of suificient 

 value or utility to be ' selective ' would be kept 

 alive and perfected. 



But we see that the intelligence which is ap- 

 pealed to, to take the place of instinct and to 

 give rise to it, uses just these partial variations 

 which tend in the direction of the instinct ; 

 so the intelligence sujiplements such partial coor- 

 dinations, makes them functional, and so keeps 

 the creature alive. In the phrase of Prof. Lloyd 

 Morgan, this prevents the ' incidence of natural 

 selection. ' So the supposition that intelligence 

 is operative turns out to be just the supposition 

 which makes the use-hypothesis unnecessary. 

 Thus kept alive, the species has all the time 

 necessary to perfect the variations required by 

 a complete instinct. And when we bear in 

 mind that the variation required is, as was 

 shown above, not on the muscular side to any 

 great extent, but in the central brain connec- 

 tions, and is a slight variation for functional 

 purposes at the best, the hypothesis of use-in- 

 heritance becomes not only unnecessary, but to 

 my mind quite superfluous. 



II. There is also another great source open 

 to the Neo-Darwinian in this matter of instinct; 

 also a psychological resource. Weismann 

 and others have shown that the influence of 

 animal intercourse, seen in maternal instruc- 

 tion, imitation, gregarious cooperation, etc., is 

 very important. "Wallace dwells upon the 

 actual facts which illustrate the ' imitative 

 factor,' as we may call it, in the personal devel- 

 opment of young animals. I have recently 

 argued that Spencer and others are in error in 

 holding that social progress demands the use- 

 hypothesis ;* since the socially-acquired actions' 

 of a species, notably man, are socially handed 

 down; giving a sort of ' social heredity ' which 

 supplements natural heredity. And when we 

 come to enquire into the actual mechanism of 

 imitation on the part of a young animal we 

 find much the same sort of function involved 



* Science, August 23, 1895, summarized in JVa- 

 ture, Vol. LII., 1895. p. 627. 



