INSTINCT AND INTELLIGENCE. 659 



man down to the lowest radiate, and upon this as absciss we erect 

 ordinates representing the degrees of intelligence, then by connecting 

 these ordinates we develop what might be called the line of intelli- 

 gence. This line, as is seen, rapidly descends from the higher to the 

 lower races of man, then makes a sudden fall from the lowest races of 

 men to the highest species of monkeys, and thence gradually descends 

 until the ordinates of intelligence become insensible, though they 

 probably still exist down to the lowest point, b. If in a similar way 

 we construct a line of instinct, it would probably rise as we pass down 

 through the lower races of men and through the animal scale, reach- 

 ing its maximum about the middle of the series among insects, and 

 again declining to the end. If, however, we were to construct a third 

 line representing the relative amounts of these two, i. e., the proportion 

 of instinct to intelligence, it would probably be a continuously rising 

 curve something like the dotted line in the diagram. The quotient 

 of instinct divided by intelligence, of acquired wisdom divided by 

 inherited wisdom, constantly increases as we go down the scale. 



Such, then, is the nature of instinct, and such its general relations 

 to intelligence. But the most important question still remains. How 

 was this wondrous faculty acquired ? Whence did it come ? How is 

 it dei'ived? In a word, what is the true theory of the origin of 

 instinct f 



The Origin op Instinct. The old theology disposes of the above 

 question, as she does so many others, in the most summary way. Ac- 

 cording to her, instincts are not acquired or derived at all. They are 

 miraculously given in perfection to the first individuals of the species, 

 to each species its several kind. But this explanation cannot satisfy 

 Science. It simply places the question beyond her domain. .To sci- 

 ence Nature is a continuous chain, and her mission is to recover every 

 link. To her a true explanation of any phenomenon consists in con- 

 necting it with other phenomena most nearly allied to it. A scientific 

 explanation or theory of instinct must connect it with intelligence on 

 the one hand and the lower phenomena of the nervous system on the 

 other must show how all these several capacities are evolved the one 

 from the other must bring them all under the universal law of evo- 

 lution. 



This, it is admitted, is no easy task. The wonderful instincts of 

 some animals have always been regarded as one of the greatest objec- 

 tions to the theory of evolution. The origin of instinct is reckoned 

 one of the hardest nuts for evolutionists to crack. The subject is 

 indeed an obscure one, but recently some light begins to break. The 

 task is indeed a hard one, but I believe we begin to understand in 

 what direction, at least, we must work. The question is yet far from 

 solved we are yet in much perplexity, but I think we hold the thread 

 which must eventually lead us out of this labyrinth! I have thought 

 much for many years on this subject, and I now give you the views 



