A Critical Examination Of The Position Of Mr. Darwin''''s Work ppt

Darwin's Work, "On The Origin Of Species," In Relation To The Complete Theory Of The Causes Of The Phenomena Of Organic Nature, by Thomas H.. Darwin's Work, "On The Origin Of Species," I

The Project Gutenberg EBook of A Critical Examination Of The Position Of

Mr Darwin's Work, "On The Origin Of Species," In Relation To The Complete Theory Of The Causes Of The Phenomena Of Organic Nature, by Thomas H Huxley

This eBook is for the use of anyone anywhere at no cost and with

almost no restrictions whatsoever You may copy it, give it away or

re-use it under the terms of the Project Gutenberg License included

with this eBook or online at www.gutenberg.org

Title: A Critical Examination Of The Position Of Mr Darwin's Work, "On The Origin Of Species," In Relation To The Complete Theory Of The Causes Of The Phenomena Of Organic Nature

Lecture VI (of VI.), Lectures To Working Men, at the

Museum of Practical Geology, 1863, On

Darwin's work: "Origin

of Species"

Author: Thomas H Huxley

Release Date: January 4, 2009 [EBook

#2926]

Language: English

*** START OF THIS PROJECT GUTENBERG EBOOK

ON THE ORIGIN OF SPECIES ***

Produced by Amy E Zelmer, and David Widger

A CRITICAL EXAMINATION

ORIGIN OF SPECIES,"

IN RELATION TO THE COMPLETE THEORY OF THE CAUSES OF THE PHENOMENA OF ORGANIC NATURE

Lecture VI (of VI.),

"Lectures To Working Men",

at the Museum of Practical

Geology, 1863, On Darwin's work: "Origin of Species".

By Thomas H Huxley

IN the preceding five lectures I haveendeavoured to give you an account ofthose facts, and of those reasonings fromfacts, which form the data upon which alltheories regarding the causes of thephenomena of organic nature must bebased And, although I have had frequentoccasion to quote Mr Darwin—as all

persons hereafter, in speaking upon thesesubjects, will have occasion to quote hisfamous book on the "Origin ofSpecies,"—you must yet remember that,wherever I have quoted him, it has notbeen upon theoretical points, or forstatements in any way connected with hisparticular speculations, but on matters offact, brought forward by himself, orcollected by himself, and which appearincidentally in his book If a man 'will'make a book, professing to discuss asingle question, an encyclopaedia, Icannot help it.

Now, having had an opportunity ofconsidering in this sort of way thedifferent statements bearing upon alltheories whatsoever, I have to lay before

you, as fairly as I can, what is Mr.Darwin's view of the matter and whatposition his theories hold, when judged bythe principles which I have previouslylaid down, as deciding our judgmentsupon all theories and hypotheses.

I have already stated to you that theinquiry respecting the causes of thephenomena of organic nature resolvesitself into two problems—the first beingthe question of the origination of living ororganic beings; and the second being thetotally distinct problem of themodification and perpetuation of organicbeings when they have already come intoexistence The first question Mr Darwindoes not touch; he does not deal with it atall; but he says—given the origin of

organic matter—supposing its creation tohave already taken place, my object is toshow in consequence of what laws andwhat demonstrable properties of organicmatter, and of its environments, such states

of organic nature as those with which weare acquainted must have come about.This, you will observe, is a perfectlylegitimate proposition; every person has aright to define the limits of the inquirywhich he sets before himself; and yet it is

a most singular thing that in all themultifarious, and, not unfrequently,ignorant attacks which have been madeupon the 'Origin of Species', there isnothing which has been more speciouslycriticised than this particular limitation Ifpeople have nothing else to urge againstthe book, they say—"Well, after all, you

see, Mr Darwin's explanation of the'Origin of Species' is not good for much,because, in the long run, he admits that hedoes not know how organic matter began

to exist But if you admit any specialcreation for the first particle of organicmatter you may just as well admit it for allthe rest; five hundred or five thousanddistinct creations are just as intelligible,and just as little difficult to understand, asone." The answer to these cavils is two-fold In the first place, all human inquirymust stop somewhere; all our knowledgeand all our investigation cannot take usbeyond the limits set by the finite andrestricted character of our faculties, ordestroy the endless unknown, whichaccompanies, like its shadow, the endlessprocession of phenomena So far as I can

venture to offer an opinion on such amatter, the purpose of our being inexistence, the highest object that humanbeings can set before themselves, is notthe pursuit of any such chimera as theannihilation of the unknown; but it issimply the unwearied endeavour toremove its boundaries a little further fromour little sphere of action.

I wonder if any historian would for amoment admit the objection, that it ispreposterous to trouble ourselves aboutthe history of the Roman Empire, because

we do not know anything positive aboutthe origin and first building of the city ofRome! Would it be a fair objection tourge, respecting the sublime discoveries

of a Newton, or a Kepler, those great

philosophers, whose discoveries havebeen of the profoundest benefit andservice to all men,—to say to them

—"After all that you have told us as tohow the planets revolve, and how they aremaintained in their orbits, you cannot tell

us what is the cause of the origin of thesun, moon, and stars So what is the use ofwhat you have done?" Yet theseobjections would not be one whit morepreposterous than the objections whichhave been made to the 'Origin of Species.'

Mr Darwin, then, had a perfect right tolimit his inquiry as he pleased, and theonly question for us—the inquiry being solimited—is to ascertain whether themethod of his inquiry is sound or unsound;whether he has obeyed the canons whichmust guide and govern all investigation, or

whether he has broken them; and it wasbecause our inquiry this evening isessentially limited to that question, that Ispent a good deal of time in a formerlecture (which, perhaps, some of youthought might have been better employed),

in endeavouring to illustrate the methodand nature of scientific inquiry in general

We shall now have to put in practice theprinciples that I then laid down

I stated to you in substance, if not inwords, that wherever there are complexmasses of phenomena to be inquired into,whether they be phenomena of the affairs

of daily life, or whether they belong to themore abstruse and difficult problems laidbefore the philosopher, our course ofproceeding in unravelling that complex

chain of phenomena with a view to get atits cause, is always the same; in all cases

we must invent an hypothesis; we mustplace before ourselves some more or lesslikely supposition respecting that cause;and then, having assumed an hypothesis,having supposed cause for the phenomena

in question, we must endeavour, on theone hand, to demonstrate our hypothesis,

or, on the other, to upset and reject italtogether, by testing it in three ways Wemust, in the first place, be prepared toprove that the supposed causes of thephenomena exist in nature; that they arewhat the logicians call 'vera causae'—truecauses;—in the next place, we should beprepared to show that the assumed causes

of the phenomena are competent toproduce such phenomena as those which

we wish to explain by them; and in the lastplace, we ought to be able to show that noother known causes are competent toproduce those phenomena If we cansucceed in satisfying these threeconditions we shall have demonstratedour hypothesis; or rather I ought to say weshall have proved it as far as certainty ispossible for us; for, after all, there is noone of our surest convictions which maynot be upset, or at any rate modified by afurther accession of knowledge It wasbecause it satisfied these conditions that

we accepted the hypothesis as to thedisappearance of the tea-pot and spoons inthe case I supposed in a previous lecture;

we found that our hypothesis on thatsubject was tenable and valid, because thesupposed cause existed in nature, because

it was competent to account for thephenomena, and because no other knowncause was competent to account for them;and it is upon similar grounds that anyhypothesis you choose to name is accepted

in science as tenable and valid

What is Mr Darwin's hypothesis? As Iapprehend it—for I have put it into ashape more convenient for commonpurposes than I could find 'verbatim' in hisbook—as I apprehend it, I say, it is, thatall the phenomena of organic nature, pastand present, result from, or are caused by,the inter-action of those properties oforganic matter, which we have calledATAVISM and VARIABILITY, with theCONDITIONS OF EXISTENCE; or, inother words,—given the existence of

organic matter, its tendency to transmit itsproperties, and its tendency occasionally

to vary; and, lastly, given the conditions ofexistence by which organic matter issurrounded—that these put together are thecauses of the Present and of the Pastconditions of ORGANIC NATURE

Such is the hypothesis as I understand

it Now let us see how it will stand thevarious tests which I laid down just now

In the first place, do these supposedcauses of the phenomena exist in nature?

Is it the fact that in nature these properties

of organic matter—atavism and variability

—and those phenomena which we havecalled the conditions of existence,—is ittrue that they exist? Well, of course, ifthey do not exist, all that I have told you in

the last three or four lectures must beincorrect, because I have been attempting

to prove that they do exist, and I take itthat there is abundant evidence that they

do exist; so far, therefore, the hypothesisdoes not break down

But in the next place comes a muchmore difficult inquiry:—Are the causesindicated competent to give rise to thephenomena of organic nature? I suspectthat this is indubitable to a certain extent

It is demonstrable, I think, as I haveendeavoured to show you, that they areperfectly competent to give rise to all thephenomena which are exhibited byRACES in nature Furthermore, I believethat they are quite competent to accountfor all that we may call purely structural

phenomena which are exhibited bySPECIES in nature On that point also Ihave already enlarged somewhat Again, Ithink that the causes assumed arecompetent to account for most of thephysiological characteristics of species,and I not only think that they are competent

to account for them, but I think that theyaccount for many things which otherwiseremain wholly unaccountable andinexplicable, and I may sayincomprehensible For a full exposition ofthe grounds on which this conviction isbased, I must refer you to Mr Darwin'swork; all that I can do now is to illustratewhat I have said by two or three casestaken almost at random

I drew your attention, on a previous

evening, to the facts which are embodied

in our systems of Classification, which arethe results of the examination andcomparison of the different members ofthe animal kingdom one with another Imentioned that the whole of the animalkingdom is divisible into five sub-kingdoms; that each of these sub-kingdoms

is again divisible into provinces; that eachprovince may be divided into classes, andthe classes into the successively smallergroups, orders, families, genera, andspecies

Now, in each of these groups, theresemblance in structure among themembers of the group is closer inproportion as the group is smaller Thus, aman and a worm are members of the

animal kingdom in virtue of certainapparently slight though reallyfundamental resemblances which theypresent But a man and a fish are members

of the same sub-kingdom 'Vertebrata',because they are much more like oneanother than either of them is to a worm,

or a snail, or any member of the other kingdoms For similar reasons men andhorses are arranged as members of thesame Class, 'Mammalia'; men and apes asmembers of the same Order, 'Primates';and if there were any animals more likemen than they were like any of the apes,and yet different from men in importantand constant particulars of theirorganization, we should rank them asmembers of the same Family, or of thesame Genus, but as of distinct Species

sub-That it is possible to arrange all thevaried forms of animals into groups,having this sort of singular subordinationone to the other, is a very remarkablecircumstance; but, as Mr Darwin remarks,this is a result which is quite to beexpected, if the principles which he laysdown be correct Take the case of theraces which are known to be produced bythe operation of atavism and variability,and the conditions of existence whichcheck and modify these tendencies Takethe case of the pigeons that I broughtbefore you; there it was shown that theymight be all classed as belonging to someone of five principal divisions, and thatwithin these divisions other subordinategroups might be formed The members ofthese groups are related to one another in

just the same way as the genera of afamily, and the groups themselves as thefamilies of an order, or the orders of aclass; while all have the same sort ofstructural relations with the wild rock-pigeon, as the members of any greatnatural group have with a real orimaginary typical form Now, we knowthat all varieties of pigeons of every kindhave arisen by a process of selectivebreeding from a common stock, the rock-pigeon; hence, you see, that if all species

of animals have proceeded from somecommon stock, the general character oftheir structural relations, and of oursystems of classification, which expressthose relations, would be just what wefind them to be In other words, thehypothetical cause is, so far, competent to

produce effects similar to those of the realcause.

Take, again, another set of veryremarkable facts,—the existence of whatare called rudimentary organs, organs forwhich we can find no obvious use, in theparticular animal economy in which theyare found, and yet which are there

Such are the splint-like bones in the leg

of the horse, which I here show you, andwhich correspond with bones whichbelong to certain toes and fingers in thehuman hand and foot In the horse you seethey are quite rudimentary, and bearneither toes nor fingers; so that the horsehas only one "finger" in his fore-foot andone "toe" in his hind foot But it is a verycurious thing that the animals closely

allied to the horse show more toes than he;

as the rhinoceros, for instance: he hasthese extra toes well formed, andanatomical facts show very clearly that he

is very closely related to the horse indeed

So we may say that animals, in ananatomical sense nearly related to thehorse, have those parts which arerudimentary in him, fully developed

Again, the sheep and the cow have nocutting-teeth, but only a hard pad in theupper jaw That is the commoncharacteristic of ruminants in general Butthe calf has in its upper jaw somerudiments of teeth which never aredeveloped, and never play the part of teeth

at all Well, if you go back in time, youfind some of the older, now extinct, allies

of the ruminants have well-developedteeth in their upper jaws; and at thepresent day the pig (which is in structureclosely connected with ruminants) haswell-developed teeth in its upper jaw; sothat here is another instance of organswell-developed and very useful, in oneanimal, represented by rudimentaryorgans, for which we can discover nopurpose whatsoever, in another closelyallied animal The whalebone whale,again, has horny "whalebone" plates in itsmouth, and no teeth; but the young foetalwhale, before it is born, has teeth in itsjaws; they, however, are never used, andthey never come to anything But othermembers of the group to which the whalebelongs have well-developed teeth in bothjaws.

Upon any hypothesis of specialcreation, facts of this kind appear to me to

be entirely unaccountable andinexplicable, but they cease to be so if youaccept Mr Darwin's hypothesis, and seereason for believing that the whalebonewhale and the whale with teeth in itsmouth both sprang from a whale that hadteeth, and that the teeth of the foetal whaleare merely remnants—recollections, if wemay so say—of the extinct whale So inthe case of the horse and the rhinoceros:suppose that both have descended bymodification from some earlier formwhich had the normal number of toes, andthe persistence of the rudimentary boneswhich no longer support toes in the horsebecomes comprehensible

In the language that we speak inEngland, and in the language of theGreeks, there are identical verbal roots,

or elements entering into the composition

of words That fact remains unintelligible

so long as we suppose English and Greek

to be independently created tongues; butwhen it is shown that both languages aredescended from one original, the Sanscrit,

we give an explanation of thatresemblance In the same way theexistence of identical structural roots, if Imay so term them, entering into thecomposition of widely different animals,

is striking evidence in favour of thedescent of those animals from a commonoriginal

To turn to another kind of illustration:

—If you regard the whole series ofstratified rocks—that enormous thickness

of sixty or seventy thousand feet that Ihave mentioned before, constituting theonly record we have of a most prodigiouslapse of time, that time being, in allprobability, but a fraction of that of which

we have no record;—if you observe inthese successive strata of rockssuccessive groups of animals arising anddying out, a constant succession, givingyou the same kind of impression, as youtravel from one group of strata to another,

as you would have in travelling from onecountry to another;—when you find thisconstant succession of forms, their tracesobliterated except to the man of science,

—when you look at this wonderfulhistory, and ask what it means, it is only a

paltering with words if you are offered thereply,—'They were so created.'

But if, on the other hand, you look on allforms of organized beings as the results ofthe gradual modification of a primitivetype, the facts receive a meaning, and yousee that these older conditions are thenecessary predecessors of the present.Viewed in this light the facts ofpalaeontology receive a meaning—uponany other hypothesis, I am unable to see,

in the slightest degree, what knowledge orsignification we are to draw out of them.Again, note as bearing upon the samepoint, the singular likeness which obtainsbetween the successive Faunae andFlorae, whose remains are preserved onthe rocks: you never find any great and

enormous difference between theimmediately successive Faunae andFlorae, unless you have reason to believethere has also been a great lapse of time

or a great change of conditions Theanimals, for instance, of the newesttertiary rocks, in any part of the world, arealways, and without exception, found to

be closely allied with those which nowlive in that part of the world For example,

in Europe, Asia, and Africa, the largemammals are at present rhinoceroses,hippopotamuses, elephants, lions, tigers,oxen, horses, etc.; and if you examine thenewest tertiary deposits, which contain theanimals and plants which immediatelypreceded those which now exist in thesame country, you do not find giganticspecimens of ant-eaters and kangaroos,

but you find rhinoceroses, elephants,lions, tigers, etc.,—of different species tothose now living,—but still their closeallies If you turn to South America,where, at the present day, we have greatsloths and armadilloes and creatures ofthat kind, what do you find in the newesttertiaries? You find the great sloth-likecreature, the 'Megatherium', and the greatarmadillo, the 'Glyptodon', and so on And

if you go to Australia you find the samelaw holds good, namely, that thatcondition of organic nature which haspreceded the one which now exists,presents differences perhaps of species,and of genera, but that the great types oforganic structure are the same as thosewhich now flourish

What meaning has this fact upon anyother hypothesis or supposition than one

of successive modification? But if thepopulation of the world, in any age, is theresult of the gradual modification of theforms which peopled it in the precedingage,—if that has been the case, it isintelligible enough; because we mayexpect that the creature that results fromthe modification of an elephantinemammal shall be something like anelephant, and the creature which isproduced by the modification of anarmadillo-like mammal shall be like anarmadillo Upon that supposition, I say,the facts are intelligible; upon any other,that I am aware of, they are not

So far, the facts of palaeontology are

consistent with almost any form of thedoctrine of progressive modification; theywould not be absolutely inconsistent withthe wild speculations of De Maillet, orwith the less objectionable hypothesis ofLamarck But Mr Darwin's views haveone peculiar merit; and that is, that theyare perfectly consistent with an array offacts which are utterly inconsistent withand fatal to, any other hypothesis ofprogressive modification which has yetbeen advanced It is one remarkablepeculiarity of Mr Darwin's hypothesisthat it involves no necessary progression

or incessant modification, and that it isperfectly consistent with the persistencefor any length of time of a given primitivestock, contemporaneously with itsmodifications To return to the case of the

domestic breeds of pigeons, for example;you have the Dove-cot pigeon, whichclosely resembles the Rock pigeon, fromwhich they all started, existing at the sametime with the others And if species aredeveloped in the same way in nature, aprimitive stock and its modifications may,occasionally, all find the conditions fittedfor their existence; and though they comeinto competition, to a certain extent, withone another, the derivative species maynot necessarily extirpate the primitive one,

or 'vice versa'

Now palaeontology shows us manyfacts which are perfectly harmonious withthese observed effects of the process bywhich Mr Darwin supposes species tohave originated, but which appear to me to

be totally inconsistent with any otherhypothesis which has been proposed.There are some groups of animals andplants, in the fossil world, which havebeen said to belong to "persistent types,"because they have persisted, with verylittle change indeed, through a very greatrange of time, while everything about themhas changed largely There are families offishes whose type of construction haspersisted all the way from thecarboniferous rock right up to thecretaceous; and others which have lastedthrough almost the whole range of thesecondary rocks, and from the lias to theolder tertiaries It is something stupendousthis—to consider a genus lasting withoutessential modifications through all thisenormous lapse of time while almost

everything else was changed andmodified.

Thus I have no doubt that Mr Darwin'shypothesis will be found competent toexplain the majority of the phenomenaexhibited by species in nature; but in anearlier lecture I spoke cautiously withrespect to its power of explaining all thephysiological peculiarities of species

There is, in fact, one set of thesepeculiarities which the theory of selectivemodification, as it stands at present, is notwholly competent to explain, and that isthe group of phenomena which Imentioned to you under the name ofHybridism, and which I explained toconsist in the sterility of the offspring ofcertain species when crossed one with

another It matters not one whit whetherthis sterility is universal, or whether itexists only in a single case Everyhypothesis is bound to explain, or, at anyrate, not be inconsistent with, the whole ofthe facts which it professes to account for;and if there is a single one of these factswhich can be shown to be inconsistentwith (I do not merely mean inexplicable

by, but contrary to) the hypothesis, thehypothesis falls to the ground,—it is worthnothing One fact with which it ispositively inconsistent is worth as much,and as powerful in negativing thehypothesis, as five hundred If I am right inthus defining the obligations of anhypothesis, Mr Darwin, in order to placehis views beyond the reach of all possibleassault, ought to be able to demonstrate