Chapter X

CHARACTERS AS ADAPTIVE AND SPECIFIC (_concluded_).

Our subject is not yet exhausted. For it remains to observe the consequences which arise from the dogma of utility as the only _raison d'etre_ of species, or of specific characters, when this dogma is applied in practice by its own promoters.

* * * * *

Any definition of "species"--excepting Nos. 1, 2, and 5, which may here be disregarded--must needs contain some such phrase as the one with which Nos. 3 and 4 conclude. This is, that peculiar characters, in order to be recognized as of specific value, must present neither more nor less than "some certain degree of distinctness." If they present more than this degree of distinctness, the form, or forms, in question must be ranked as generic; while if they present less than this degree of distinctness, they must be regarded as varietal--and this even if they are known to be mutually sterile. What, then, is this certain degree of distinctness? What are its upper and lower limits? This question is one that cannot be answered. From the very nature of the case it is impossible to find a uniform standard of distinction whereby to draw our boundary lines between varieties and species on the one hand, or between species and genera on the other. One or two quotations will be sufficient to satisfy the general reader upon this point.

Mr. Wallace himself alludes to "the great difficulty that is felt by botanists in determining the limits of species in many large genera," and gives as examples well-known instances where systematic botanists of the highest eminence differ hopelessly in their respective estimates of "specific characters." Thus:--

"Mr. Baker includes under a single species, Rosa canina, no less
than twenty-eight named varieties distinguished by more or less
constant characters, and often confined to special localities, and
to these are referred about seventy of the species of British and
continental botanists. Of the genus Rubus or bramble, five British
species are given in Bentham's _Handbook of British Flora_, while
in the fifth edition of Babington's _Manual of British Botany_,
published about the same time, no less than forty-five species are
described. Of willows (Salix) the same two works enumerate fifteen
and thirty-one species respectively. The hawkweeds (Hieracium) are
equally puzzling, for while Mr. Bentham admits only seven British
species, Professor Babington describes no less than seventy-two,
besides several named varieties[125]."

[125] _Darwinism_, p. 77.

Mr. Wallace goes on to quote further instances, such as that of Draba verna, which Jordan has found to present, in the south of France alone, no less than fifty-two permanent varieties, which all "come true from seed, and thus present all the characteristics of a true species"; so that, "as the plant is very common almost all over Europe, and ranges from North America to the Himalayas, the number of similar forms over this wide area would probably have to be reckoned by hundreds, if not by thousands[126]."

[126] _Darwinism_, p. 77.

One or two further quotations may be given to the same general effect, selected from the writings of specialists in their several departments.

"There is nothing that divides systematists more than what
constitutes a genus. Species that resemble each other more than
other species, is perhaps the best definition that can be given.
This is obviously an uncertain test, much depending on individual
judgement and experience; but that, in the evolution of forms, such
difficulties should arise in the limitation of genera and species
was inevitable. What is a generic character in one may be only a
specific character in another. As an illustration of the uncertain
importance of characters, I may mention the weevil genus
_Centrinus_ in which the leading characters in the classification
of the family to which it belongs are so mixed that systematists
have been content to keep the species together in a group that
cannot be defined.... No advantage or disadvantage is attached,
apparently, to any of the characters. There are about 200 species,
all American.

The venation of the wings of insects is another example of
modifications without serving any special purpose. There is no vein
in certain Thripidae, and only a rudiment or a single vein in
Chalcididae. There are thousands of variations more or less marked,
some of the same type with comparatively trivial variation, others
presenting distinct types, even in the same family, such genera,
for example, as _Polyneura_, _Tettigetra_, _Huechys_, &c. in the
Cicadidae.

Individual differences have often been regarded as distinctive of
species; varieties also are very deceptive, and races come very
near to species. A South-American beetle, _Arescus histrio_, has
varieties of yellow, red, and black, or these colours variously
intermixed, and, what is very unusual, longitudinal stripes in some
and transverse bars in others, and all taken in the same locality.
Mr. A. G. Butler, of the British Museum, is of opinion that 'what
is generally understood by the term species (that is to say, a
well-defined, distinct, and constant type, having no near allies)
is non-existent in the Lepidoptera, and that the nearest approach
to it in this order is a constant, though but slightly differing,
rare or local form--that genera, in fact, consist wholly of a
gradational series of such forms (Ann. Mag. Nat. Hist. 5, xix.
103)[127].'"

[127] Pascoe, _The Darwinian Theory of the Origin of Species_, 1891,
pp. 31-33, and 46.

So much as regards entomology, and still living forms. In illustration of the same principles in connexion with palaeontological series, I may quote Wuertenberger, who says:--

"With respect to these fossil forms [i.e. multitudinous forms of
fossil Ammonites], it is quite immaterial whether a very short or a
somewhat longer part of any branch be dignified with a separate
name, and regarded as a species. The prickly Ammonites, classed
under the designation of Armata, are so intimately connected that
it becomes impossible to separate the accepted species sharply from
one another. The same remark applies to the group of which the
manifold forms are distinguished by their ribbed shells, and are
called Planulata[128]."

[128] _Neuer Beitrag zum geologischen Beweis der Darwinischen
Theorie_, 1873.

I had here supplied a number of similar quotations from writers in various other departments of systematic work, but afterwards struck them out as superfluous. For it is not to be anticipated that any competent naturalist will nowadays dispute that the terms "variety," "species," and "genus" stand for merely conventional divisions, and that whether a given form shall be ranked under one or the other of them is often no more than a matter of individual taste. From the nature of the case there can be no objective, and therefore no common, standards of delimitation. This is true even as regards any one given department of systematic work; but when we compare the standards of delimitation which prevail in one department with those which prevail in another, it becomes evident that there is not so much as any attempt at agreeing upon a common measure of specific distinction.

But what, it may well be asked, is the use of thus insisting upon well-known facts, which nobody will dispute? Well, in the first place, we have already seen, in the last chapter, that it is incumbent on those who maintain that all species, or even all specific characters, must be due to natural selection, to tell us what they mean by a species, or by characters as specific. If I am told to believe that the definite quality A is a necessary attribute of B, and yet that B is "not a distinct entity," but an undefinable abstraction, I can only marvel that any one should expect me to be so simple. But, without recurring to this point, the use of insisting on the facts above stated is, in the second place, that otherwise I cannot suppose any general reader could believe them in view of what is to follow. For he cannot but feel that the cost of believing them is to render inexplicable the mental processes of those naturalists who, in the face of such facts, have deduced the following conclusions.

The school of naturalists against which I am contending maintains, as a generalization deduced from the theory of natural selection, that all species, or even all specific characters, must necessarily owe their origin to the principle of utility. Yet this same school does not maintain any such generalization, either with regard to varietal characters on the one hand, or to generic characters on the other. On the contrary, Professor Huxley, Mr. Wallace, and all other naturalists who agree with them in refusing to entertain so much as the abstract possibility of any cause other than natural selection having been productive of species, fully accept the fact of other causes having been largely concerned in the production of varieties, genera, families, and all higher groups, or of the characters severally distinctive of each. Indeed, Mr. Wallace does not question what appears to me the extravagant estimate of Professor Cope, that the non-adaptive characters distinctive of those higher groups are fully equal, in point of numbers, to the adaptive. But, surely, if the theory of evolution by natural selection is, as we all agree, a true theory of the origin of species, it must likewise be a true theory of the origin of genera; and if it be supposed essential to the integrity of the theory in its former aspect that all specific characters should be held to be useful, I fail to see how, in regard to its latter aspect, we are so readily to surrender the necessary usefulness of all generic characters. And exactly the same remark applies to the case of constant "varieties," where again the doctrine of utility as universal is not maintained. Yet, according to the general theory of evolution, constant varieties are what Darwin termed "incipient species," while species are what may be termed "incipient genera." Therefore, if the doctrine of utility as universal be conceded to fail in the case of varieties on the one hand and of genera on the other, where is the consistency in maintaining that it must "necessarily" hold as regards the intermediate division, species? Truly the shade of Darwin may exclaim, "Save me from my friends." And truly against logic of this description a follower of Darwin must find it difficult to argue. If one's opponents were believers in special creation, and therefore stood upon some definite ground while maintaining this difference between species and all other taxonomic divisions, there would at least be some issue to argue about. But when on the one hand it is conceded that species are merely arbitrary divisions, which differ in no respect as to the process of their evolution from either varieties or genera, while on the other hand it is affirmed that there is thus so great a difference in the result, all we can say is that our opponents are entangling themselves in the meshes of a sheer contradiction.

Or, otherwise stated, specific characters differ from varietal characters in being, as a rule, more pronounced and more constant: on this account advocates of utility as universal apply the doctrine to species, while they do not feel the "necessity" of applying it to varieties. But now, generic and all higher characters are even more constant and more pronounced than specific characters--not to say, in many cases, more generally diffused over a larger number of organisms usually occupying larger areas. Therefore, _a fortiori_, if for the reasons above stated evolutionists regard it as a necessary deduction from the theory of natural selection that all specific characters must be useful, much more ought it to be a necessary deduction from this theory that all generic, and still more all higher, characters must be useful. But, as we have seen, this is not maintained by our opponents. On the contrary, they draw the sharpest distinction between specific and all other characters in this respect, freely conceding that both those below and those above them need not--and very often do not--present any utilitarian significance.

Although it appears to me that this doctrine is self-contradictory, and on this ground alone might be summarily dismissed, as it is now held in one or other of its forms by many naturalists, I will give it a more detailed consideration in both its parts--namely, first with respect to the distinction between varieties and species, and next with respect to the distinction between species and genera.

* * * * *

Until it can be shown that species are something more than merely arbitrary divisions, due to the disappearance of intermediate varietal links; that in some way or another they _are_ "definite entities," which admit of being delineated by the application of some uniform or general principles of definition; that, in short, species have only then been classified as such when it has been shown that the origin of each has been due to the operation of causes which have not been concerned in the production of varieties;--until these things are shown, it clearly remains a gratuitous dogma to maintain that forms which have been called species differ from forms which have been called varieties in the important respect, that they (let alone each of all their distinctive characters) must necessarily have been due to the principle of utility. Yet, as we have seen, even Mr. Wallace allows that a species is "not a distinct entity," but "an assemblage of individuals which have become somewhat modified in structure, form, and constitution"; while estimates of the kinds and degrees of modification which are to be taken as of specific value are conceded to be undefinable, fluctuating, and in not a few cases almost ludicrously divergent.

Perhaps one cannot more forcibly present the rational value of this position than by noting the following consequences of it. Mr. Gulick writes me that while studying the land-shells of the Sandwich Islands, and finding there a rich profusion of unique varieties, in cases where the intermediate varieties were rare he could himself have created a number of species by simply throwing these intermediate varieties into his fire. Now it follows from the dogma which we are considering, that, by so doing, not only would he have created new species, but at the same time he would have proved them due to natural selection, and endowed the diagnostic characters of each with a "necessarily" adaptive meaning, which previously it was not necessary that they should present. Before his destruction of these intermediate varieties, he need have felt himself under no obligation to assume that any given character at either end of the series was of utilitarian significance: but, after his destruction of the intermediate forms, he could no longer entertain any question upon the matter, under pain of being denounced as a Darwinian heretic.

Now the application is self-evident. It is a general fact, which admits of no denial, that the more our knowledge of any flora or fauna increases, the greater is the number of intermediate forms which are brought to light, either as still existing or as having once existed. Consequently, the more that such knowledge increases, the more does our catalogue of "species" diminish. As Kerner says, "bad species" are always multiplying at the expense of "good species"; or, as Oscar Schmidt (following Haeckel) similarly remarks, if we could know as much about the latter as we do about the former, "all species, without any exception, would become what species-makers understand by 'bad species'[129]." Hence we see that, just as Mr. Gulick could have created good species by secretly destroying his intermediate varieties, so has Nature produced her "good species" for the delectation of systematists. And just as Mr. Gulick, by first hiding and afterwards revealing his intermediate forms, could have made the self-same characters in the first instance necessarily useful, but ever afterwards presumably useless, so has Nature caused the utility of diagnostic characters to vary with our knowledge of her intermediate forms. It belongs to the essence of our theory of descent, that in _all_ cases these intermediate forms must either be now existing or have once existed; and, therefore, that the work of species-makers consists in nothing more than marking out the _lacunae_ in our knowledge of them. Yet we are bound to believe that wherever these _lacunae_ in our knowledge occur, there occurs also the objective necessity of causation as utilitarian--a necessity, however, which vanishes so soon as our advancing information supplies the intermediate forms in question. It may indeed appear strange that the utility or non-utility of organic structures should thus depend on the accidents of human knowledge; but this is the Darwinian faith, and he who doubts the dogma is to be anathema.

[129] _The Doctrine of Descent and Darwinism_, Eng. Trans. p. 102.

Turning next to the similar distinction which it is sought to draw between species and genera, here it will probably be urged, as I understand it to be urged by Mr. Wallace, that generic characters (and still more characters of families, orders, &c.) refer back to so remote a state of things that utility may have been present at their birth which has disappeared in their maturity. In other words, it is held that all generic characters were originally specific characters; that as such they were all originally of use; but that, after having been rendered stable by heredity, many of them may have ceased to be of service to the descendants of those species in which they originated, and whose extinction has now made it impossible to divine what that service may have been.

Now, in the first place; this is not the interpretation adopted by Darwin. For instance, he expressly contrasts such cases with those of vestigial or "rudimentary" structures, pointing out that they differ from vestigial structures in respect of their permanence. One quotation will be sufficient to establish the present point.

"A structure which has been developed through long-continued
selection, when it ceases to be of service to a species, generally
becomes variable, as we see with rudimentary organs, for it will no
longer be regulated by this same power of selection. But when, from
the nature of the organism and of the conditions, modifications
have been induced which are unimportant for the welfare of the
species, they may be, and apparently often have been, transmitted
in nearly the same state to numerous, otherwise modified,
descendants[130]."

[130] _Origin of Species_, p. 175.

Here, and in the context, we have a sufficiently clear statement of Darwin's view--first, that unadaptive characters may arise in _species_ as "fluctuating variations, which sooner or later become _constant_ through the nature of the organism and of surrounding conditions, as well as through the intercrossing of distinct individuals, but _not_ through natural selection"[131]; second, that such unadaptive characters may then be transmitted in this their stable condition to species-progeny, so as to become distinctive of genera, families, &c.; third, that, on account of such characters not being afterwards liable to diverse adaptive modifications in different branches of the species-progeny, they are of more value as indicating lines of pedigree than are characters which from the first have been useful; and, lastly, they are therefore now empirically recognized by systematists as of most value in guiding the work of classification. To me it appears that this view is not only perfectly rational in itself, but likewise fully compatible with the theory of natural selection--which, as I have previously shown, is _primarily_ a theory of adaptive characters, and therefore not necessarily a theory of _all_ specific characters. But to those who think otherwise, it must appear--and does appear--that there is something wrong about such a view of the case--that it was not consistent in the author of the _Origin of Species_ thus to refer non-adaptive generic characters to a parentage of non-adaptive specific characters. Nevertheless, as a matter of fact, Darwin was perfectly consistent in putting forth this view, because, unlike Wallace, he was not under the sway of any antecedent dogma erroneously deduced from the theory of natural selection.

[131] _Ibid._ p. 176: italics mine.

Next without reference to Darwin's authority, let us see for ourselves where the inconsistency really lies. To allow that generic characters may be useless, while denying that specific characters can ever be so (unless correlated with others that are useful), involves an appeal to the argument from ignorance touching the ancestral habits, life-conditions, &c., of a parent species now extinct. Well, even upon this assumption of utility as obsolete, there remains to be explained the "stability" of useless characters now distinctive of genera, families, orders, and the rest. We know that specific characters which have owed their origin to utility and have afterwards ceased to present utility, degenerate, become variable, inconstant, "rudimentary," and finally disappear. Why, then, should these things not happen with regard to useless generic distinctions? Still more, why should they not happen with regard to family, ordinal, and class distinctions? On the lines against which I am arguing it would appear impossible that any answer to this question can be suggested. For what explanation can be given of the contrast thus presented between the obsolescence of specific characters where previous utility is demonstrable, and the permanence of higher characters whose previous utility is assumed? As we have already seen, Mr. Wallace himself employs this consideration of permanence and constancy against the view that any cause other than natural selection can have been concerned in the origin and maintenance of _specific_ characters. But he does not seem to see that the consideration cuts two ways--and much more forcibly against his views than in favour of them. For while, as already shown in the chapter before last, it is sufficiently easy to dispose of the consideration as Wallace uses it (by simply pointing out with Darwin that any causes other than natural selection which may have been concerned in the genesis of _specific_ characters, must, if equally uniform in their operation, equally give rise to permanence and constancy in their results); on the other hand, it becomes impossible to explain the stability of useless _generic_ characters, if, as Wallace's use of the argument requires, natural selection is the only possible cause of stability. The argument is one that cannot be played with fast and loose. Either utility is the sole condition to the stability of _any_ diagnostic character (in which case it is not open to Mr. Wallace to assume that all _generic_ or higher characters which are now useless have owed their origin to a past utility); or else utility is not the sole condition to stability (in which case his use of the present argument in relation to _specific_ characters collapses). We have seen, indeed, in the chapter before last, that his use of the argument collapses anyhow, or quite irrespective of his inconsistent attitude towards generic characters, with which we were not then concerned. But the point now is that, as a mere matter of logic, the argument from stability as Wallace applies it to the case of specific characters, is incompatible with his argument that useless generic characters may originally have been useful specific characters. It can scarcely be questioned that the transmutation of a species into a genus must, as a rule, have allowed time enough for a newly acquired--i.e. peculiar specific-character--to show some signs of undergoing degeneration, if, as supposed, the original cause of its development and maintenance was withdrawn when the parent species began to ramify into its species-progeny. Yet, as Darwin says, "it is notorious that specific characters are more variable than generic[132]." So that, upon the whole, I do not see how on grounds of general reasoning it is logically possible to maintain Mr. Wallace's distinction between specific and generic characters in respect of necessary utility.

[132] _Origin of Species_, p. 122.

But now, and lastly, we shall reach the same conclusion if, discarding all consideration of general principles and formal reasoning, we fasten attention upon certain particular cases, or concrete facts. Thus, to select only two illustrations within the limits of genera, it is a diagnostic feature of the genus _Equus_ that small warty callosities occur on the legs. It is impossible to suggest any useful function that is now discharged by these callosities in any of the existing species of the genus. If it be assumed that they must have been of some use to the species from which the genus originally sprang, the assumption, it seems to me, can only be saved by further assuming that in existing species of the genus these callosities are in a vestigial condition--i. e. that in the original or parent species they performed some function which is now obsolete. But against these assumptions there lies the following fact. The callosities in question are not similarly distributed through all existing species of the genus. The horse has them upon all his four legs, while other species have them only upon two. Therefore, if all specific characters are necessarily due to natural selection, it is manifest that these callosities are _not_ now vestigial: on the contrary, they _must_ still be--or, at best, have recently been--of so much importance to all existing species of the genus, that not only is it a matter of selection-value to all these species that they should possess these callosities; but it is even a matter of selection-value to a horse that he should possess four of them, while it is equally a matter of selection-value to the ass that he should possess only two. Here, it seems to me, we have once more the doctrine of the necessary utility of specific characters reduced to an absurdity; while at the same time we display the incoherency of the distinction between specific characters and generic characters in respect of this doctrine. For the distinction in such a case amounts to saying that a generic character, if evenly distributed among all the species, need not be an adaptive character; whereas, if any one of the species presents it in a slightly different form, the character must be, on this account, necessarily adaptive. In other words, the uniformity with which a generic character occurs among the species of the genus is taken to remove that character from the necessarily useful class, while the absence of such uniformity is taken as proof that the character must be placed within the necessarily useful class. Which is surely no less a _reductio ad absurdum_ with regard to the generic character than the one just presented with regard to its variants as specific characters. And, of course, this twofold absurdity is presented in all cases where a generic character is unequally distributed among the constituent species of a genus.

But here is an illustration of another class of cases. Mr. Tomes has shown that the molar teeth of the Orang present an extraordinary and altogether superfluous amount of attachment in their sockets--the fangs being not only exceedingly long, and therefore deeply buried in the jaw-bone, but also curving round one another, so as still further to strengthen the whole[133]. In the allied genera of anthropoid apes there is no such abnormal amount of attachment. Now, the question is, of what conceivable use can it _ever_ have been, either to the existing genus, or to its parent species, that such an abnormal amount of attachment should obtain? It certainly is not required to prevent dislocation of the teeth, seeing that in all allied genera, and even in man himself, the amount of attachment is already so great that teeth will break before they can be drawn by anything short of a dentist's forceps. Therefore I conclude that this peculiarity in the dentition of the genus must have arisen in its parent species by way of what Darwin calls a "fluctuating variation," without utilitarian significance. And I adduce it in the present connexion because the peculiarity is one which is equally unamenable to a utilitarian explanation, whether it happens to occur as a generic or a specific character.

[133] _A Manual of Dental Anatomy_, p. 455.

Numberless similar cases might be quoted; but probably enough has now been said to prove the inconsistency of the distinction which our opponents draw between specific and all higher characters in respect of utility. In point of fact, a very little thought is enough to show that no such distinction admits of being drawn; and, therefore, that any one who maintains the doctrine of utility as universal in the case of specific characters, must in consistency hold to the same doctrine in the case of generic and all higher characters. And the fact that our opponents are unable to do this becomes a virtual confession on their part of the futility of the generalization which they have propounded[134].

[134] It may be observed that this distinction was not propounded by
Mr. Wallace--nor, so far as I am aware, by anybody else--until
he joined issue with me on the subject of specific characters.
Whether he has always held this important distinction between
specific and generic characters, I know not; but, as
originally enunciated, his doctrine of utility as universal
was subject to no such limitation: it was stated
unconditionally, as applying to all taxonomic divisions
indifferently. The words have already been quoted on page 180;
and, if the reader will turn to them, he may further observe
that, prior to our discussion, Mr. Wallace made no allowance
for the principle of correlation, which, as we have seen,
furnishes so convenient a loop-hole of escape in cases where
even the argument from our ignorance of possible utility
appears absurd. In his latest work, however, he is much less
sweeping in his statements. He limits his doctrine to the case
of "specific characters" alone, and even with regard to them
makes unlimited drafts upon the principle of correlation.

On what then do Mr. Wallace and his followers rely for their great distinction between specific and all other characters in respect of utility? This is the final and fundamental question which I must leave these naturalists themselves to answer; for my whole contention is, that it is unanswerable. But although I am satisfied that they have nothing on which to base their generalization, it seems worth while to conclude by showing yet one further point. And this is, that these naturalists themselves, as soon as they quit merely abstract assertions and come to deal with actual facts, contradict their own generalization. It is worth while to show this by means of a few quotations, that we may perceive how impossible it is for them to sustain their generalization in the domain of fact.

As it is desirable to be brief, I will confine myself to quoting from Mr. Wallace.

"Colour may be looked upon as a necessary result of the highly
complex chemical constitution of animal tissues and fluids. The
blood, the bile, the bones, the fat, and other tissues have
characteristic, and often brilliant colours, which we cannot
suppose to have been determined for any special purpose as colours,
since they are usually concealed. The external organs and
integuments, would, by the same general laws, naturally give rise
to a greater variety of colour[135]."

[135] _Darwinism_, p. 297.

Surely comment is needless. Have the colour of external organs and integuments nothing to do with the determining of specific distinctions by systematists? Or, may we not rather ask, are there any other "characters" which have had more to do with their delineation of animal species? Therefore, if "the external organs and integuments naturally give rise to a greater variety of colours," for non-utilitarian reasons, than is the case with internal organs and tissues; while even the latter present, for similarly non-utilitarian reasons, such variety and intensity of colours as they do; must it not follow that, on the ground of the "Laws of Growth" alone, Mr. Wallace has conceded the entire case as regards "a large proportional number of specific characters" being non-adaptive--"spontaneous" in their occurrence, and "meaningless" in their persistence?

Once more:--

"The enormously lengthened plumes of the bird of paradise and of
the peacock, can, however, have no such use [i.e. for purposes of
defence], but must be rather injurious than beneficial in the
birds' ordinary life. The fact that they have been developed to so
great an extent in a few species is an indication of such perfect
adaptation to the conditions of existence, such complete success in
the battle for life, that there is, in the adult male at all
events, a surplus of strength, vitality, and growth-power, which is
able to expend itself in this way without injury. That such is the
case is shown by the great abundance of most of the species which
possess these wonderful superfluities of plumage.... Why, in allied
species, the development of accessory plumes has taken different
forms, we are unable to say, except that it may be due to that
individual variability which has served as a starting-point for so
much of what seems to us strange in form, or fantastic in colour,
both in the animal and vegetable world[136]."

[136] _Darwinism_, pp. 292-3.

Here, again, one need only ask, How can such statements be reconciled with the great dogma, "which is indeed a necessary deduction from the theory of Natural Selection, namely, that none of the definite facts of organic nature, no special organ, no characteristic form or marking can exist, but which must now be, or once have been, _useful_"? Can it be said that the plumes of a bird of paradise present "no characteristic form," or the tail of a peacock "no characteristic marking"? Can it be held that all the "fantastic colours," which Darwin attributes to sexual selection, and all the "strange forms" in the vegetable world which present no conceivable reference to adaptation, are to be ascribed to "individual variability" without reference to utility, while at the same time it is held, "as a necessary deduction from the theory of Natural Selection," that _all_ specific characters must be "_useful_"? Or must we not conclude that we have here a contradiction as direct as a contradiction can well be[137]?

[137] Since the above was written both Mr. Gulick and Professor
Lloyd Morgan have independently noticed the contradiction.

Nor is it any more possible to reconcile these contradictory statements by an indefinite extension of the term "correlation," than we found it to be in the cases previously quoted. It might indeed be logically possible, howsoever biologically absurd, to attribute the tail of a peacock--with all its elaboration of structure and pattern of colour, with all the drain that its large size and weight makes upon the vital resources of the bird, with all the increased danger to which it exposes the bird by rendering it more conspicuous, more easy of capture, &c.--to correlation with some useful character peculiar to peacocks. But to say that it is due to correlation with general "vitality," is merely to discharge the doctrine of correlation of any assignable meaning. Vitality, or "perfect adaptation to the conditions of existence," is obviously a prime condition to the occurrence of a peacock's tail, as it is to the occurrence of a peacock itself; but this is quite a different thing from saying that the specific characters which are presented by a peacock's tail, although useless in themselves, are correlated with some other and useful specific characters of the same bird--as we saw in a previous chapter with reference to secondary sexual characters in general. Therefore, when Mr. Wallace comes to the obvious question why it is that even in "allied species," which must be in equally "perfect adaptation to the conditions of existence," there are no such "wonderful superfluities of plumage," he falls back--as he previously fell back--on whatever unknown _causes_ it may have been which produced the peacock's tail, when the primary _condition_ to their operation has been furnished by "complete success in the battle for life."

I have quoted the above passages, not so much for the sake of exposing fundamental inconsistencies on the part of an adversary, as for the sake of observing that they constitute a much truer exposition of "Darwinism" than do the contradictory views expressed in some other parts of the work bearing that title. For even if characters of so much size and elaboration as the tail of a peacock, the plumes of a bird of paradise &c., are admitted to be due to non-utilitarian causes, much more must innumerable other characters of incomparably less size and elaboration be mere "superfluities." Without being actually deleterious, "a large proportional number of specific characters," whose utility is not apparent, must _a fortiori_ have been due to "individual variation," to "general laws which determine the production" of such characters--or, in short, to some causes other than natural selection. And this, I say, is a doctrine much more in harmony with "Darwinism" than is the contradictory doctrine which I am endeavouring to resist.

But once again, and still more generally, after saying of "the delicate tints of spring foliage, and the intense hues of autumn," that "as colours they are unadaptive, and appear to have no more relation to the well-being of plants themselves than do the colours of gems and minerals," Mr. Wallace proceeds thus:--

"We may also include in the same category those algae and fungi
which have bright colours--the red snow of the Arctic regions, the
red, green, or purple seaweeds, the brilliant scarlet, yellow,
white or black agarics, and other fungi. All these colours are
probably the direct results of chemical composition or molecular
structure, and being thus normal products of the vegetable
organism, need no special explanation from our present point of
view; and the same remark will apply to the varied tints of the
bark of trunks, branches and twigs, which are often of various
shades of brown and green, or even vivid reds and yellows[138]."

[138] _Darwinism_, p. 302.

Here, as Mr. Gulick has already observed, "Mr. Wallace seems to admit that instead of useless specific characters being unknown, they are so common and so easily explained by 'the chemical constitution of the organism' that they claim no special attention[139]." And whatever answer Mr. Wallace may make to this criticism, I do not see how he is to meet the point at present before us--namely, that, upon his own showing, there are in nature numberless instances of "characters which are useless without being hurtful," and which nevertheless present absolute "constancy." If, in order to explain the contradiction, he should fall back upon the principle of correlation, the case would not be in any way improved. For, here again, if the term correlation were extended so as to include "the chemical constitution or the molecular structure of the organism," it would thereby be extended so as to discharge all Darwinian significance from the term.

[139] _American Journal of Science_, Vol. XL. art. I. on _The
Inconsistencies of Utilitarianism as the Exclusive Theory of
Organic Evolution_.

_Summary._

I will conclude this discussion of the Utility question by recapitulating the main points in an order somewhat different from that in which they have been presented in the foregoing chapters. Such a variation may render their mutual connexions more apparent. But it is only to the main points that allusion will here be made, and, in order the better to show their independent character, I will separately number them.

* * * * *

1. The doctrine of utility as universal, whether with respect to species only or likewise with respect to specific characters, is confessedly an _a priori_ doctrine, deduced by way of general reasoning from the theory of natural selection.

2. Being thus founded exclusively on grounds of deduction, the doctrine cannot be combated by any appeal to facts. For this question is not one of fact: it is a question of reasoning. The treatment of our subject matter is logical: not biological.

3. The doctrine is both universal and absolute. According to one form of it _all_ species, and according to another form of it _all_ specific characters, must _necessarily_ be due to the principle of utility.

4. The doctrine in both its forms is deduced from a definition of the theory of natural selection as a theory, and the sole theory, of the origin of _species_; but, as Professor Huxley has already shown, it does not really follow, even from this definition, that all specific _characters_ must be "necessarily useful." Hence the two forms of the doctrine, although coincident with regard to species, are at variance with one another in respect of specific characters. Thus far, of course, I agree with Professor Huxley; but if I have been successful in showing that the above definition of the theory of natural selection is logically fallacious, it follows that the doctrine in both its forms is radically erroneous. The theory of natural selection is not, accurately speaking, a theory of the origin of species: it is a theory of the origin and cumulative development of adaptations, to whatever order of taxonomic division these may happen to belong. Thus the premisses of the deduction which we are considering collapse: the principle of utility is shown not to have any other or further reference to species, or to specific characters, than it has to fixed varieties, genera, families, &c., or to the characters severally distinctive of each.

5. But, quitting all such antecedent considerations, we next proceeded to examine the doctrine _a posteriori_, taking the arguments which have been advanced in favour of the doctrine, other than those which rest upon the fallacious definition. These arguments, as presented by Mr. Wallace, are two in number.

First, it is represented that natural selection must occupy the whole field, because no other principle of change can be allowed to operate in the presence of natural selection. Now I fully agree that this statement holds as regards any principle of change which is deleterious, but I cannot agree that it does so as regards any such principle which is merely neutral. No reason has ever been shown why natural selection should interfere with "indifferent" characters--to adopt Professor Huxley's term--supposing such to have been produced by any of the agencies which we shall presently have to name. Therefore this argument--or rather assertion--goes for nothing.

Mr. Wallace's second argument is, that utility is the only principle which can endow specific characters with their characteristic stability. But this again is mere assertion. Moreover, it is assertion opposed alike to common sense and to observable fact. It is opposed to common sense, because it is obvious that any other principle would equally confer stability on characters due to it, provided that its action is constant, as Darwin expressly held. Again, this argument is opposed to fact, because we know of thousands of cases where peculiar characters are stable, which, nevertheless, cannot possibly be due to natural selection. Of such are the Porto Santo rabbits, the niata cattle, the ducks in St. James' Park, turkeys, dogs, horses, &c., and, in the case of plants, wheat, cabbage, maize, &c., as well as all the hosts of climatic varieties, both of animals and plants, in a state of nature. Indeed, on taking a wide survey of the facts, we do not find that the principle of utility is any better able to confer stability of character than are many other principles, both known and unknown. Nay, it is positively less able to do so than are some of these other principles. Darwin gives two very probable reasons for this fact; but I need not quote them a second time. It is enough to have seen that this argument from stability or constancy is no less worthless than the previous one. Yet these are the only two arguments of a corroborative kind which Mr. Wallace adduces whereby to sustain his "necessary deduction."

6. At this point, therefore, it may well seem that we need not have troubled ourselves any further with a generalization which does not appear to have anything to support it. And to this view of the case I should myself agree, were it not that many naturalists now entertain the doctrine as an essential article of their Darwinian creed. Hence, I proceeded to adduce considerations _per contra_.

Seeing that the doctrine in question can only rest on the assumption that there is no cause other than natural selection which is capable of originating any single species--if not even so much as any single specific character--I began by examining this assumption. It was shown first that, on merely antecedent grounds, the assumption is "infinitely precarious." There is absolutely no justification for the statement that in all the varied and complex processes of organic nature natural selection is the only possible cause of specific change. But, apart altogether from this _a priori_ refutation of the dogma, our analysis went on to show that, in point of actual fact, there are not a few well-known causes of high generality, which, while having no connexion with the principle of utility, are demonstrably capable of originating species and specific characters--if by "species" and "specific characters" we are to understand organic types which are ranked as species, and characters which are described as diagnostic of species. Such causes I grouped under five different headings, viz. Climate, Food, Sexual Selection, Isolation, and Laws of Growth. Sexual Selection and Isolation are, indeed, repudiated by Mr. Wallace; but, in common I believe with all biologists, he accepts the other three groups of causes as fully adequate to produce such kinds and degrees of modification as are taken to constitute specific distinction. And this is amply sufficient for our present purposes. Besides, under the head of Sexual Selection, it does not signify in the present connexion whether or not we accept Darwin's theory on this subject. For, in any case, the facts of secondary sexual characters are indisputable: these characters are, for the most part, specific characters: and they cannot be explained by the principle of utility. Even Mr. Wallace does not attempt to do so; and the explanation which he does give is clearly incompatible with his doctrine touching the necessarily life-serving value of all specific characters. Lastly, the same has to be said of the Laws of Growth. For we have just seen that on the grounds of this principle likewise Mr. Wallace abandons the doctrine in question. As regards Isolation, much more remains to be said in the ensuing portion of this work, while, as regards Climatic Variation, there are literally innumerable cases where changes of specific type are known to have been caused by this means.

7. To the latter class of cases, however, it will be objected that these changes of specific type, although no doubt sufficiently "stable" so long as the changed conditions remain constant, are found by experiment not to be hereditary; and this clearly makes all the difference between a true specific change and a merely fictitious appearance of it.

Well, in the first place, this objection can have reference only to the first two of the five principles above stated. It can have no reference to the last three, because of these heredity constitutes the very foundation. This consideration ought to be borne in mind throughout. But now, in the second place, even as regards changes produced by climate and food, the reply is nugatory. And this for three reasons, as follows.

(_a_) No one is thus far entitled to conclude against the possible transmission of acquired characters; and, so long as there is even so much as a possibility of climatic (or any other admittedly non-utilitarian) variations becoming in this way hereditary, the reply before us merely begs the question.

(_b_) Even supposing, for the sake of argument, that acquired characters can never in any case become congenital, there remains the strong probability--sanctioned as such even by Weismann--that changed conditions of life may not unfrequently act upon the material of heredity itself, thus giving rise to specific changes which are from the first congenital, though not utilitarian. Indeed, there are not a few facts (Hoffmann's plants, Weismann's butterflies, &c.), which can only be explained either in this way, or as above (_a_). And in the present connexion it is immaterial which of these alternative explanations we choose to adopt, seeing that they equally refute our opponents' objection. And not only do these considerations--(_a_) and (_b_)--refute this particular objection; they overturn on new and independent grounds the whole of our opponents' generalization. For the generalization is, that the principle of utility, acting through natural selection, is "necessarily" the sole principle which can be concerned in hereditary changes of specific type. But here we perceive both a possibility (_a_) and a probability (_b_), if not indeed a certainty, that quite other principles have been largely concerned in the production of such changes.

(_c_) Altogether apart from these considerations, there remains a much more important one. For the objection that fixed--or "stable"--climatic varieties differ from true species in not being subject to heredity, raises the question--What are we to understand by a "species"? This question, which was thus far purposely left in abeyance, had now to be dealt with seriously. For it would clearly be irrational in our opponents to make this highly important generalization with regard to species and specific characters, unless they are prepared to tell us what they mean by species, and therefore by characters as specific. In as far as there is any ambiguity on this point it makes entirely for our side in the debate, because even any small degree of uncertainty with regard to it would render the generalization in question proportionally unsound. Yet it is notorious that no word in existence is more vague, or more impossible to define, than the word "species." The very same men who at one time pronounce their great generalization with regard to species, at another time asseverate that "a species is not a definite entity," but a merely abstract term, serving to denote this that and the other organic type, which this that and the other systematist regards as deserving such a title. Moreover it is acknowledged that systematists differ among themselves to a wide extent as to the kinds and degrees of peculiarity which entitle a given form to a specific rank. Even in the same department of systematic work much depends on merely individual taste, while in different departments widely different standards of delimination are in vogue. Hence, our _reductio ad absurdum_ consists in this--that whether a given form is to be regarded as necessarily due to natural selection, and whether all its distinctive characters are to be regarded as necessarily utilitarian characters, will often depend on whether it has been described by naturalist A or by naturalist B. There is no one criterion--there is not even any one set of criteria--agreed upon by naturalists for the construction of specific types. In particular, as regards the principle of heredity, it is not known of one named species in twenty--probably not in a hundred--whether its diagnostic characters are hereditary characters; while, on the other hand, even in cases where experiment has proved "constant varieties" to be hereditary--and even also cross-sterile with allied varieties--it is only some three or four living botanists who for these reasons advocate the elevation of such varieties to the rank of species. In short, as we are not engaged on any abstract question touching the principles on which species ought to have been constituted by their makers, but upon the actual manner in which they have been, the criterion of heredity must needs be disregarded in the present discussion, as it has been in the work of systematists. And the result of this is, that any objection to our introducing the facts of climatic variation in the present discussion is excluded. In particular, so far as any question of heredity is concerned, all these facts are as assuredly as they are cogently relevant. It is perfectly certain that there is "a large proportional number" of named species--particularly of plants--which further investigation would resolve into climatic varieties. With the advance of knowledge, "bad species" are always increasing at the expense of "good species," so that we are now justified in concluding with Kerner, Haeckel, and other naturalists best qualified to speak on this subject, that if we could know as much about the past history and present relations of the remaining good species as we do about the bad, all the former, without exception, would become resolved into the latter. In point of fact, and apart altogether from the inductive experience on which this conclusion is based, the conclusion follows "as a necessary deduction" from the general theory of descent. For this theory essentially consists in supposing either the past or the present existence of intermediate varietal forms in all cases, with the consequence that "good species" serve merely to mark _lacunae_ in our knowledge of what is everywhere a finely graduated process of transmutation. Hence, if we place this unquestionably "necessary deduction" from the general theory of descent side by side with the alleged "necessary deduction" from the theory of natural selection, we cannot avoid the following absurdity--Whether or not a given form is to be regarded as necessarily due to natural selection, and all its characters necessarily utilitarian, is to be determined, and determined solely, by the mere accident of our having found, or not having found, either in a living or in a fossil state, its varietal ancestry.

8. But this leads us to consider the final and crowning incongruities which have been dealt with in the present chapter. For here we have seen, not only that our opponents thus draw a hard and fast line between "varieties" and "species" in regard to "necessary origin" and "necessary utility," but that they further draw a similar line between "species" and "genera" in the same respects. Yet, in accordance with the general theory of evolution, it is plainly as impossible to draw any such line in the one case as it is to do so in the other. Just as fixed varieties are what Darwin called "incipient species," so are species incipient genera, genera incipient families, and so on. Evolutionists must believe that the process of evolution is everywhere the same. Nevertheless, while admitting all this, the school of Huxley contradicts itself by alleging some unintelligible exception in the case of "species," while the school of Wallace presses this exception so as to embrace "specific characters." Indeed Mr. Wallace, while maintaining that all specific characters must necessarily be useful, maintains at the same time that any number of varietal characters on the one hand, and a good half of generic characters on the other, are probably useless. Thus he contradicts his argument from the "constancy of specific characters" (seeing that generic characters are still more constant), as later on we saw that he contradicts his deductive generalization touching their necessary utility, by giving a non-utilitarian explanation of whole multitudes of specific characters. I need not, however, again go over the ground so recently traversed; but will conclude by once more recurring to the only explanation which I have been able to devise of the otherwise inexplicable fact, that in regard to this subject so many naturalists still continue to entangle themselves in the meshes of absurdity and contradiction.

* * * * *

The only conceivable explanation is, that these naturalists have not yet wholly divested themselves of the special creation theory. Although professing to have discarded the belief that "species" are "definite entities," differing in kind from "varieties" on the one hand and from "genera" on the other, these writers are still imbued with a vague survival of that belief. They well know it to belong to the very essence of their new theory that "species" are but "pronounced varieties," or, should we prefer it, "incipient genera"; but still they cannot altogether escape the pre-Darwinian conception of species as organic units, whose single mode of origin need not extend to other taxonomic groups, and whose characters therefore present some exceptional significance to the scientific naturalist. So to speak, such divinity doth still hedge a species, that even in the very act of declaring it but an idol of their own creation, these naturalists bow before their fetish as something that is unique--differing alike in its origin and in its characters from the varieties beneath and the genera above. The consequence is that they have endeavoured to reconcile these incompatible ideas by substituting the principle of natural selection for that of super-natural creation, where the particular case of "species" is concerned. In this way, it vaguely seems to them, they are able to save the doctrine of some one mode of origin as appertaining to species, which need not "necessarily" appertain to any other taxonomic division. All other such divisions they regard, with their pre-Darwinian forefathers, as merely artificial constructions; but, likewise with these forefathers, they look upon species as natural divisions, proved to be such by a single and necessary mode of origin. Hence, Mr. Wallace expressly defines a species with reference to this single and necessary mode of origin (_see_ above, p. 235), although he must be well aware that there is no better, or more frequent, proof of it in the case of species, than there is in that of somewhat less pronounced types on the one hand (fixed varieties), or of more pronounced types on the other (genera, families, &c.). Hence, also, the theory of natural selection is defined as _par excellence_ a theory of the origin of species; it is taken as applying to the particular case of the origin of species in a peculiarly stringent manner, or in a manner which does not apply to the origin of any other groups. And I believe that an important accessory reason of the continuance of this view for more than thirty years after the publication of the _Origin of Species by means of Natural Selection_, is to be found in the title of that work. "Natural Selection" has thus become verbally associated with "Origin of Species," till it is thoughtlessly felt that, in some way or another, natural selection must have a peculiar reference to those artificially delineated forms which stand anywhere between a fixed variety and a so-called genus. This verbal association has no doubt had the effect of still further preserving the traditional halo of mystery which clings to the idea of a "species." Hence it comes that the title which Darwin chose--and, looking to the circumstances of the time, wisely chose--for his great work, has subsequently had the effect of fostering the very idea which it was the object of that work to dissipate, namely, that species are peculiar entities, which differ more or less in origin or kind from all other taxonomic groups. The full title of this work is--_The Origin of Species by means of Natural Selection: or the Preservation of Favoured Races in the Struggle for Life_. Now, supposing that instead of this its author had chosen some such title as the following:--_The Origin of Organic Types by means of Adaptive Evolution: or Survival of the Fittest Forms in the Struggle for Life_. Of course this would have been a bad substitute from various points of view; but could any objection have been urged against it from our present point of view? I do not see that there could. Yet, if such had been the title, I have little doubt that we should never have heard of those great generalizations with regard to species and specific characters, the futility of which it has been the object of these chapters to expose.

* * * * *

In conclusion, it only remains to reiterate that in thus combating what appears to me plainly erroneous deductions from the theory of natural selection, I am in no wise combating that theory itself. On the contrary, I hope that I am rendering it no unimportant service by endeavouring to relieve it of a parasitic growth--an accretion of false logic. Regarding as I do the theory of natural selection as, primarily, a theory of the origin (or cumulative development) of adaptations, I see in merely non-adaptive characters--be they "specific" or other--a comparatively insignificant class of phenomena, which may be due to a great variety of incidental causes, without any further reference to the master-principle of natural selection than that in the presence of this principle none of these non-adaptive characters can be actively deleterious. But that there may be "any number of indifferent characters" it is no part of the theory of natural selection to deny; and all attempts to foist upon it _a priori_ "deductions" opposed alike to the facts of nature and to the logic of the case, can only act to the detriment of the great generalization which was expressly guarded from such fallacies by the ever-careful judgement of Darwin.

APPENDICES AND NOTES

APPENDIX I.

ON PANMIXIA.

There are several points of considerable theoretical importance connected with Panmixia, which were omitted from the text, in order to avoid distracting attention from the main issue which is there under consideration. These side issues may now be appropriately presented in the form in which they were published in _Nature_, March 13, 1890[140]. After stating, in almost the same words, what has already been said in