450 



NA TURE 



{Sept. 7, 1882 



discussing, for example, the question of the general intel- 

 ligence of ants, Dr. Romanes speaks of "the difficulty of 

 drawing the line between purposeless instinct and pur- 

 posive intelligence." He then goes on to say, " It will be 

 remembered that our test of instinctive as distinguished 

 from truly intelligent action is simply whether all indi- 

 viduals of a species perform similar adaptive movements 

 under the stimulus supplied by similar and habitual cir- 

 cumstances, or whether they manifest individual and 

 peculiar adaptive movements to meet the exigencies of 

 novel and peculiar circumstances" (p. 123). Now this 

 distinction between instinct and reason, when it comes to 

 be applied, does not seem to be essentially different from 

 the distinction between mental and reflex action. The 

 distinction of instinct as having an element of conscious- 

 ness from mere reflex action which is unconscious, seems 

 to vanish in the actual treatment of the subject ; and the 

 way of answering the question as to instinct that suggests 

 itself most strongly is to define it with Mr. Spencer as 

 " compound reflex action," placing both instinct and 

 reflex action, as merely mechanical processes, in opposi- 

 tion to all conscious action. 



If we take this view, we must regard all animals from 

 the lowest to the highest as having a certain measure of 

 " general intelligence." In the higher animals this 

 general intelligence may be as highly developed as the 

 mechanical processes described by the term instinct. 

 For example, Dr. Romanes says, in speaking of the 

 beaver, " It is really impossible by the closest study of 

 the psychology of this animal to distinguish the web of 

 instinct from the woof of intelligence ; the two principles 

 seem here to have been so intimately woven together, that 

 in the result, as expressed by certain particular actions, it 

 cannot be determined how much we are to attribute to 

 mechanical impulse, and how much to reasoned purpose" 

 (P- 367)- Now there seems to be an advantage here in 

 confining the term instinct to the mechanical processes 

 and calling all the rest " general intelligence." And Dr. 

 Romanes, except in the Introduction, seems to have 

 looked upon the facts in this way. But in considering 

 the question how the terms should be defined, the diffi- 

 culty no doubt presented itself that reflex action, instinct, 

 and reason are usually thought of as an ascending series. 

 This, however, is merely because the animals in which 

 reflex, instinctive, and rational action respectively are 

 most prominent, form an ascending series in the scale of 

 intelligence. The difficulty disappears when we regard 

 all animals as having some general intelligence ; for we 

 can arrange them in an ascending series (as Dr. Romanes 

 proposes) according to the amount of consciousness pos- 

 sessed by them ; contrasting all along the line " non- 

 mental neuro-muscular adjustment " (simple or "reflex," 

 and compound or "instinctive") with the mental life 

 properly so called. 



That all animals have some consciousness, some 

 'general intelligence," is regarded as probable by Dr. 

 Romanes ; and perhaps the most interesting portions of 

 the book are the early chapters in which he proves the 

 presence of an element of consciousness in animals very 

 low in the zoological scale. " Even the headless oyster," 

 he quotes from an unpublished MS. of Mr. Darwin, 

 " ;cems to profit by experience." And this power of 

 profiting by experience, it must be remembered, is the 



test of rational as distinguished from instinctive action. 

 But we find evidence of conscious purpose even below 

 mollusca. Dr. Romanes records an observation made by 

 himself on rotifers, and says that if we were to depend 

 upon appearances alone, this one observation would be 

 sufficient ground for attributing conscious determination 

 to these microscopical organisms (p. 19). Then after 

 quoting " some observations relating to the lowest of all 

 animals and made by a competent person," he remarks 

 that " although we may suppose that the adaptive move- 

 ments described by Mr. Carter were non-mental, it still 

 remains wonderful that these movements should be exhi- 

 bited by such apparently unorganised creatures \amcebce\ 

 seeing that as to the remoteness of the end attained, no 

 less than the complex refinement of the stimulus to which 

 their adaptive response was due, the movements in ques- 

 tion rival the most elaborate of non- mental adjustments 

 elsewhere performed by the most highly organised of 

 nervous systems" (p. 22). 



Now these phenomena, if they are ascribed to mind at 

 all, certainly cannot be ascribed to instinct. And it is 

 scarcely possible, consistently with the principles laid 

 down by Dr. Romanes, to deny that they are mental. It 

 therefore seems as if we must admit the presence of the 

 intelligent and volitional element in Protozoa ; and this 

 view suggests itself more strongly when we consider the 

 nature of the movements of these animals, and when at 

 the same time we remember Mr. Spencer's description of 

 instinct passing into intelligence by losing its perfectly 

 unhesitating or "automatic" character. 



In the higher (as regards morphological organisation) 

 but less plastic animals Ccelenterata and Echinodermata, 

 Dr. Romanes finds nothing that cannot be explained as 

 reflex action. Taking this into account along with the 

 facts already mentioned, we may infer that the opposition 

 between intelligent and mechanical action which shows 

 itself in the tendency of each to encroach on the region 

 possessed at any particular time by the other, is present 

 from the beginning of life; and thus the division of all 

 that is included in mind into free intelligence and 

 organised habit (instinctive or reflex) subordinate to it, is 

 seen to be preferable to the division into reflex action, 

 instinct, and reason. 



The kind of opposition that must always exist between 

 these two things when they have become distinct may be 

 made clear by bringing together the general results of the 

 chapter on Instinct in the " Origin of Species," and of 

 those portions of Mr. Spencer's "Principles of Psycho- 

 logy" mentioned by Dr. Romanes in his preface. Mr. 

 Darwin showed, in the chapter referred to, how the most 

 complicated instincts may be formed out of purely reflex 

 actions by natural selection : and Mr. Spencer had 

 already shown in the first edition of the " Psychology " 

 how instinctive processes pass into rational processes 

 when they become too complex to be performed unhesi- 

 tatingly ; and how, on the other hand, rational processes 

 when they are often repeated become habits, and may at 

 length be fixed by heredity as secondary instincts. More 

 recently Mr. Spencer has shown grounds for thinking 

 that natural selection is most important in the early stages 

 of evolution, while the formation of habits which at first 

 are conscious, but at last pass into instincts, is most im- 

 portant in_the later stages of evolution. But in any case 



