Feb. 14, 1884] 



NATURE 



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impossible, to decide whether or not a given action implies the 

 presence of the mind-element — /.<-. conscious as distinguished 

 from unconscious adaptation ; liut this is altogether a separate 

 matter, and has nothing to do with the question of defining 

 instinct in a manner which shall be formally exclusive, on the 

 one hand of reflex action, and on the other of reason." But I 

 venture to think that the difficulties of application are from the 

 very nature of the case insuperable, and that the definition is 

 therefore, whatever its logical value, practically of little service. 



Again, on p. 17 of his recent volume, Mr. Romanes tells us 

 that "the only test [of the con-cious choice element] we have 

 is to ask whether the ailjustments displayed are invariably the 

 same under the same circumstances of stimulation. The only 

 distinction between adjustive movements due to reflex action, 

 and adjustive movements accompanied by mental perception, 

 consists in the former depending on inherited mechanisms with- 

 in the nervous system being so constructed as to effect particular 

 adjustive movements in response to particular stimulations, 

 while the latter are independent of any such inherited adjustment 

 of special mechanisms to the exigencies of special circum- 

 stances." And a little further on (p. 18) he says, " It is enough 

 to point to the variable and incalculaljle character of mental 

 adjustments as distinguished from the constant and foreseeable 

 character of reflex adjustments." All which may be very true. 

 But it seems to cut away the ground from under his defini- 

 tion of instinct. f"or surely what he says here of reflex actions 

 is also true of instinctive actions. Surely in.^linctive actions 

 "depend on inherited mechanisms within the nervous system 

 being so constructed as to effect particular adjustive movements 

 in response to particular stimulations." Surely we may also 

 point to the "constant and foreseeable character of instiuctive 

 adjustments." 



But though an instinctive action may involve no consciousness 

 in the individual, it may have involved consciousness, during the 

 l^rocess of its evolution, in the ancestors of the individual. In 

 this way, perhaps, we may admit consciousness into our defini- 

 tion of instinct. But if we hark back to ancestcrs in one case, 

 we may fairly do so in another. And since the secondary in- 

 stincts of the individual involved intelligence in his ancestors, we 

 must import not only consciousness but intelligence into our 

 definition of instinct. If we admit lapsed consciousness, why 

 not admit lapsed intelligence ? Our definition will then become : 

 Instinct is reflex action into which is imported (ance-trally) the 

 elements of consciousness and intelligence. In which case 

 instinct and reason run together. 



It seems to me, therefore, that the psychological definition of 

 instinct lacks that definiteness of application which is not merely 

 desirable but essential. If I might be permitted to paraphrase 

 Mr. Ron anes I would say, " I am persuaded that if we are to 

 have any approach to definiteness in the terms which we employ 

 — not to say to clearness in our ideas concerning the things of 

 which w-e speak — \\.\s," not "desirable to restrict the word 

 instinct to mental as distinguished from non-mental activity." 

 And this just because it is so "difficult, or even impossible, to 

 decide whether or not " instinctive actions " imply the presence 

 of the mind-element — i.e. conscious as distinguished from un- 

 conscious adaptation." 



5. — A Physiological Definition of Instinct 



" Instinctive actions are actions which, owing to their frequent 

 repetition, become so habitual in the course of generations that 

 all the individuals of the same species automatically perform the 

 ■ ame actions under the stimulus supplied by the same appropriate 

 circumstances." This physiological definition of instinct, which 

 is incidentally given by Mr. Romanes {"Animal Intelligence," 

 pp. 16-17), i5^> if I mistake not, of more practical and scientific 

 value than the psychological definition which immediately fol- 

 lows, and which introduces " the element of consciousness "and 

 " faculties of mind." 



Were it impossible to define instinct in such a manner as to 

 be formally exclusive, on the one hand, of reflex action, and, on 

 the other, of intelligent (or selective) action, without having 

 recourse to the associated phenomena of consciousness, then it 

 might be advisable to introduce consciousness into our definitions 

 for the sake of giving them a Ingical status. And Mr. Herbert 

 Spencer seems to see this difficulty when he defines or describes 

 instinct as compound reflex action. But, though reflex action 

 shades into instinctive action, and instinctive action (as seen in 

 the ])henomena described by Mr. Romanes, under the heading 

 "The Plasticity of Instinct") into intelligent action, still some 



such definitions as the following would .'eem sufiiciei.tly to 

 answ'er to the demand for formal exclusiveness : — 



1. Reflex Act iotis are actions taking place in, or performed by, 

 an individual in virtue of his possession of a general type of 

 nervous organisation. 



2. Instinctive Actions are actions performed by the individual 

 in virtue of his possession of a special type of nervous organisa- 

 tion, that is, a type of organisation common to his species. 



3. Intelligent (or Selective) Actions are actions performed by 

 an inf ividual in virtue of his possession of an individual nervous 

 organisation, that is, an organisation special to himself. 



If we call the foundation type of nervous organi aticn ^in the 

 mamm-'lii, for example) a, the special modification of that type 

 (in all dogs, for example) b, and the individual modification de- 

 veloped in some individual (say Dr. Huggins's "Kepler") c ; then 

 reflex acticns are the outcome of a, instil ctive actions the out- 

 come of a -^ /', and selective or intelligent actions the outcome of 

 a-\-6 + e. 



That there are difficulties in the application of these defini- 

 tions to special cases I readily admit, but I venture to submit 

 that they are by no means of so grave a nature as those involved 

 in the psychological definitions advocated by Mr. Romanes. 



I need not say here that such definitions do not by any means 

 imply the absence of consciousness, since I have devoted a 

 special section to T/ic Place of Consciousness with the special ob- 

 ject of showing that the doctrine of determinism, which I accept, 

 maintains the parallelism or identity of psychosis and neurosis. 



6. — The Origin and Development of Instincts 

 This article has already exceeded the length to which it was 

 intended to run. On this head, therefore, I must be brief. The 

 problem of the origin and development of instincts comes to 

 this — How^ has it come about that certain nervous structures, 

 and the actions which are their external and obvious manifesta- 

 tions, are developed in all the members of a certain species ? It 

 is clear that such a development of certain structures and their 

 corresponding actions in all the individuals of a particular spe- 

 cies must ansuer to a widely felt need. The actions answer to 

 circumstances of frequent occurrence in the life-history of the 

 species, just as intelligent actions "answer to circumstances of 

 comparatively rare occurrence in the life-history of the species " 

 ("An. In.," p. 17). The question is — How far is the equili- 

 bration direct, i.e. by adaptation, and how far is it indirect, i.e. 

 by natural selection ? To discuss this question would require a 

 separate article. I content myself with giving two quotations, 

 the former from Mr. Darwin, the latter from Mr. Spencer. 

 " I believe that most instincts are the accumulated result, through 

 natural selection, of slight and profitable modifications of other 

 instincts, which modifications I look at as due to the same 



causes which produce variations in corporeal structures 



But in the case of the many instincts which, as I believe, have 

 not at all originated in hereditary habit, I do not doubt that they 

 have been strengthened and perfected by habit ; just in the same 

 manner as we may select corporeal structures conducing to fleel- 

 ness of pace, but likewise improve this quality by training in 

 each generation " (quoted " Ment. Ev. in Ans.," p. 264). So 

 far Mr. Darwin. Mr. Spencer says: "The equilibration ol 

 organisms that are comparatively passive is necessarily effected 

 indirectly by the action of incident forces on the species as a 

 whole. But along with the gradual evolution of organisn s 

 having some activity, there grows up a kind of equilibration 

 that is relatively direct. In proportion as the activity increases, 

 direct equilibration plays a more important part. Until, when 

 the nervo-muscular apparatus becomes greatly developed, and 

 the power of varying the actions to fit the varying requirements 

 becomes considerable, the share taken by direct equilibriii n 

 rises into co-ordinate importance" ("Princ. Biol.," vol. p. 4fS). 

 It seems to me that we have here substantial agreement as to 

 the part played by indirect equilibration in laying the foundation, 

 and the part played by direct equilibration in perfecting the 

 superstructure. (I venture to think that Mr. Romanes some- 

 what mistakes Mr. Spencer's position with regard to the " very 

 subordinate importance of natural selection as an evolving 

 source of instinct," and with regard to the question of "lapsed 

 intelligence. ') 



7. Conclusion 

 One or two words in conclusion by w ay of summary. 

 I. While fully admitting the great interest that attaches to the 

 study of the inferred mental faculties of the higher brutes, I 

 believe that, from the ejective nature of the animal mind and the 



