A man bom blind, who had lived among others bom blind, could not be made to believe in the possibility of perceiving a distant object without first perceiving all the objects in between. Yet vision perfomia this miracle. In a certain sense the blind man is right, since vision, hav- ing its origin in the stimulation of the retina, by the vi- brations of the light, is nothing else, in fact, but a retinal touch. Such is indeed the scientific explanation, for the function of science is just to express all perceptions in terms of touch. But we have shown elsewhere that the philosophical explanation of perception (if it may still be called an explanation) must be of another kind.' Now instinct also is a knowledge at a distance. It has the same relation to inteUigence that vision has to touch. Science cannot do otherwise than express it in terms of intelligence; but in so doing it constructs an imitation of instinct rather than penetrates within it.
Any one can convince himself of this by studying the ingenious theories of evolutionist biology. They may be reduced to two tj-pes, which are often intermingled. One type, following the principles of neo-DaiTvinism, regards instinct as a sum of accidental differences preserved by selection: such and such a useful behavior, naturally adopted by the individual in virtue of an accidental pre- disposition of the germ, has been transmitted from germ MalHre et rrttmMrt, chap. i.
n.i THE NATURE OF INSTINCT 169
to germ, waiting for chance to add fresh improvements to it by the same method. The other type regards instinct as lapsed intelligence: the action, found useful by the species or by certain of its representatives, is supposed to have engendered a habit, which, by hereditary trans- mission, has become an instinct. Of these two types of theory, the first has the advantage of being able to bring in hereditary transmission without raising grave objection; for the accidental modification which it places at the origin of the instinct is not supposed to have been acquired by the individual, but to have been inherent in the germ. But, on the other hand, it is absolutely incapable of ex- plaining instincts as sagacious as those of most insects. These instincts surely could not have attained, all at once, their present degree of complexity; they have probably evolved; but, in a hypothesis like that of the neo-Darwin- ians, the evolution of instinct could have come to pass oidy by the progressive addition of new pieces which, in some way, by happy accidents, came to fit into the old. Now it is evident that, in most cases, instinct could not have perfected itself by simple accretion: each new piece really requires, if all is not to be spoiled, a complete recasting of the whole. How could mere chance work a recast- ing of the kind? I agree that an accidental modifica- tion of the germ may be passed on hereditarily, and may somehow wait for fresh accidental modifications to come and comphcate it. I agree also that natural selection may eliminate all those of the more complicated forms of instinct that are not fit to survive. Still, in order that the life of the instinct may evolve, complications fit to survive have to be produced. Now they will be produced only if, in certain cases, the addition of a new element brings about the correlative change of all the old elements. No one will maintain that chance could perform such a
(CHAP.
miracle: in one form or another we shall appeal to in- telligence. We shall suppose that it is by an effort, more or less conscioas, that the living being develops a higher instinct. But then we shall have to admit that an acquired habit can become hereditary, and that it does so regularly enough to ensure an evolution. The thing is doubtful, to put it mildly. Even if we could refer the instincts of animals to habits intelligently acquired and hereditarily transmitted, it is not clear how this sort of explanation cpuld be extended to the vegetable world, where effort is never intelligent, even supposing it is sometimes con- scious. And yet, when we see with what sureness and precision climbing plants use their tendiils, what mar- velously combined manoeuvres the orchids perform to procure their fertilization by means of insects," how can we help thinking that these are so many instincts?
This is not saying that the theory of the neo-Darwinians must be altogether rejected, any more than that of the neo-Lamarckians. The first are probably right in holding that evolution takes place from germ to germ rather than from individual to individual; the second are right in saying that at the origin of instinct there is an effort {although it is something quite different, we believe, from an irUelligerU effort). But the former are probably wrong when they make the evolution of instinct an accidental evolution, and the latter when they regard the effort from which instinct proceeds as an individual effort. The effort by which a species modifies its instinct, and modifies itself as well, must be a. much deeper thing, dependent solely neither on circumstances nor on individuals. It is not purely accidental, although accident has a large place in it; and it does not depend solely on the initia^
See the two works of Darwio, Climbuig PlanU and The Ftrhii- tation ol Orchvl* by InstcU.
tive of individuals, although individuals collaborate in it. Compare the different forms of the same instinct in different species of hymenoptera. The impression de- rived is not always that of an increasing complexity made of elements that have been added together one after the other. Nor does it suggest the idea of steps up a ladder. Rather do we think, in many cases at least, of the circum- ference of a circle, from different points of which these different varieties have started, all facing the same centre, all making an effort in that direction, but each approach- ing it only to the extent of its means, and to the extent also to which this central point has been illumined for it. In other words, instinct is everywhere complete, but it is more or less simplified, and, above all, simpUfied differently. On the other hand, in cases where we do get the impression of an ascending scale, as if one and the same instinct had gone on complicating itself more and more in one direction and along a straight line, the species which are thus ar- ranged by their instincts into a linear series are by no means always akin. Thus, the comparative study, in recent years, of the social instinct in the different apidae proves that the instinct of the meliponines is intennediary in complexity between the still rudimentary tendency of the humble bees and the consummate science of the true bees; yet there can be no kinship between the bees and the meliponines.' Most hkely, the degree of complexity of these different societies has nothing to do with any greater or smaller number of added elements. We seem rather to be before a musical theme, which had first been transposed, the theme as a whole, into a certain number of tones and on which, still the whole theme, different variations had been played, some very simple, others very skilful.
' Buttel-Reepen, "Die phylogenetiache Entatehung des Bieuen- nutea" (,Biol. CentraMiU, xxiii. igO'i), p. lOtt in particular.
As to the original theme, it is everywhere and nowhere. It is in vain that we try to express it in terms of any idea: it must have been, originally. /e// rather than thought. We get the same impression before the paralyzing instinct of certain wasps. We know that the different species of hymenoptera that have this paralyzing instinct lay their eggs in spiders, beetles or caterpillars, which, having first been subjected by the wasp to a skilful surgical operation, will go on hving motionless a certain number of days, and thus provide the larvae with fresh meat. In the sting which they give to the nerve-centres of their victim, in order to destroy its power of moving without killing it, these different species of hjTnenoptera take into account, so to speak, the different species of prey they respectively attack. The Scolia, which attacks a larva of the rose- beetle, stings it in one point only, but in this point the motor ganglia are concentrated, and those ganglia alone: the stinging of other ganglia might cause death and putre- faction, which it must avoid.' The yellow-winged Sphex, which has chosen the cricket for its victim, knows that the cricket has three nerve-centres which serve its three pairs of legs — or at least it acts as if it knew this. It stings the insect first under the neck, then behind the prothorax, and then where the thorax joins the abdomen.* The Ammophila Hirsuta gives nine successive strokes of its sting upon nine nerve-centres of its caterpillar, and then seizes the head and squeezes it in its mandibles, enough to cause paralysis without death." The general theme is "the necessity of paralyzing without killing"; the vari- ations are subordinated to the structure of the victim on which they are played. No doubt the operation is not
' F&bre, Smivaiira enlomatogiqtia, 3" sine, Paris, 1890, pp. I.fl9.
• Fftbre, SouvenirM entcmologiqurK, 1" eirie, 3" Mition, Paris, 1804, pp. 03 fl.
* Fftbre, Nouvcaiu touvtnin entomoiogiqua, Ptuia, 1882, pp. U S.
always perfect. It has recently been shown that the Ammophila soraetinses kills the caterpillar instead of paralyzing it, that sometimes also it paralyzes it incom- pletely.' But, because instinct is, like intelligence, fallible, because it also shows individual deviations, it does not at all follow that the instinct of the Ammophila has been acquired, as has been claimed, by tentative intelligent experiments. Even supposing that the Ammophila has come in counse of time to recognize, one after another, by tentative experiment, the points of its victim which must be stung to render it motionless, and also the special treatment that must be inflicted on the head to bring about paralysis without death, how can we imagine that elements BO special of a knowledge so precise have been regularly transmitted, one by one, by heredity? If, in all our present experience, there were a single indisputable example of a transmission of this kind, the inheritance of acquired characters would be questioned by no one. As a matter of fact, the hereditary transmission of a contracted habit is effected in an irregular and far from precise manner, supposing it is ever really effected at all.
But the whole difficulty comes from our desire to ex- press the knowledge of the hymenoptera in terms of in- telligence. It is this that compels us to compare the Ammophila with the entomologist, who knows the cater- pillar as he knows everything else — from the outside, and without having on his part a special or vital interest. The Ammophila, we imagine, must learn, one by one, like the entomologist, the positions of the nerve-centree of the caterpillar — must acquire at least the practical knowledge of these positions by trying the effects of ita sting. But there is no need for such a view if we suppose a sympathy (in the etj-mological sense of the word) between
' Peckham, Watpi, SolUary and Social, WeatmioeUr, 1905, pp. 26 B.
174 Creative Evolution
the Anunophila and its victim, which teaches it from within, so to say, concerning the vulnerability of the caterpillar. This feeling of v-ulnerability might owe noth- ing to outward perception, but result from the mere presence together of the Ammophila and the caterpillar, considered no longer as two organisms, but as two activities. It would express, in a concrete fonn, the rdoiion of the one to the other. Certainly, a scientific theory cannot appeal to considerations of this kind. It must not put action before organization, sympathy before perception and know- ledge. But, once more, either philosophy has nothing to see here, or its rfile begins where that of science ends.