This is a fresh, well-conceived collection on one of the most persistent problems in the philosophy of biology--the species problem. Unlike most anthologies, but like many species, it is cohesive and integrated. Current promotions. Bestsellers in Evolution. The Largest Avian Radiation.
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Acknowledgments Doi:. Introduction Doi:. Contributors Doi:. I: Monism, Pluralism, Unity, and Diversity. II: Species and Life's Complications. IV: Species in Mind and Culture. V: Species Begone! Index Doi:. Compliance with permission from the rights holder to display this image online prohibits further enlargement or copying.
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The branch of the phylogenetic tree. Sucha group is known as a stemspecies is a taxon is whether of PSC versions between merely important distinction or to stem a of descendants to contain species only particular required. The latter position is definitive of contain all and only such descendants cladism, whereasthe former, generally describedas evolutionary taxonomy, requires some further criterion for deciding which are acceptablesubsetsof.
First, what constitutes the division of a lineage into two distinct lineages? Second, what constitutes and hencequali6esa group as a stem species a lineageand its descendantsas a species or, indeed, as any other taxonomic rank? The traditional answer to the mst question is that a lineage has divided when two components of it are reproductively isolated from one another, but the difficulties raisedin connectionwith the BSCsuggestthat this answer is inadequate.
Examplessuch as oaks suggest that reproductive isolation is not necessaryfor the diVision of a lineage, and worries about the lack of gene flow within apparently well-de6nedspeciessuggest that it is not sufficient either. An illuminating diagnosis of the difficulty here is provided by Templeton , who distinguishes geneticexchangeability, the familiar graphic ability to exchange genetic material between organisms, and demo that '" extent the to two between exists which , organisms exchangeability they share the samefundamentalniche p.
The problem with asexual taxa and with a variety of taxa for which gene exchangeis limited is that Tile boundaries de6ned by demographic exchangeability are broader than those de6ned by genetic exchangeability. Conversely, for casesin which well-de6ned speciespersist despite gene exchange, the boundaries de6ned Dupre: ofthe Impossibilityof a MonisticAccountof Species by genetic exchangeability are broader than those defined by demographic exchangeability p.
In the light of these considerations, Templeton proposes the cohesion speciesconcept CSC. It is not entirely clear how this concept should be interpreted. But it is cl"ear from earlier discussion that such an application is not what Templeton intends. Earlier, he defines the CSC as lithe most inclusive population of individuals having the potential for phenotypic cohesion through intrinsic ". A central and convincing motivation for this definition is the claim that a range of such mechanismspromotes phenotypic cohesion, of which genetic exchange and genetic isolation are only two.
Equally important are genetic drift cohesion through common descent , natural selection, and various ecological, developmental, and historical constraints. The basictask, according to Templeton, is to Ilidentify those mechanisms that help maintain a group as an evolutionary lineage" p. What, then, is an evolutionary lineage? The significanceof the conflicting criteria of genetic and demographic exchangeability is that they show it to be impossibleto define that lineage in terms of any unitary theoretical criterion.
Rather, lineages must first be identified as cohesive groups through which evolutionary changesflow , and only then can we ask what mechanisms promote this cohesion, and to what extent the identified groups exhibit genetic or demographic exchangeability. PresumablyI this initial identification of lineagesmust be implemented by investigation of patterns of phenotypic innovation and descentover time. With the abandonmentof any generalaccountof speciationor any unitary accountof the coherenceof the species,it appearsthat specieswill be no more than whatever groups can be clearly distinguished from related or similar groups.
This approachmay seemtheoretically unsatisfying, but to the extent that it reflects the fact that there are a variety of mechanismsof speciationand a variety of mechanisms whereby the coherenceof the speciesis maintained, it would also seemto be the best conceptwe can hope for. This conclusion makespressing the secondquestion distinguished above: How do we assign taxonomic rank, especially speciesrank, to a particular lineage or set of lineages?
A prima facie advantage of the BSC is that it provides a clear solution to this problem: a speciesis the smallestgroup of. The difficulty is that this definition would leave one with speciesranging from huge and diverse syngameons to clonal strains with a handful of individuals. PluralismUnity and Diversity tween the theoretical account of a species and a practically useful classification would surely be severed. The question that must be faced, then , is whether from the PSC point of view the idea that the species is the basal taxonomic unit - where taxonomy is conceived as providing a practically useful classification - can be maintained.
Abandoning the BSC will take care of species that look unsatis factorily large by allowing a variety of cohesion mechanisms apart from reproductive isolation , but it will tend to imply the presence of disturbingly small species. Frequently there are clearly distinguishable groups of organisms subspecies, varieties , geographical races below the species level.
There is no reason to suppose that these groups are not monophyletic and no reason to suppose that they are not , at least for the moment , evolving independently. There is no doubt that such groups are often clearly distinguishable , and indeed for many purposes classification at this level is the most important.
Stebbins , notes , for instance, that foresters are often more concerned with geographic races than species and indeed can be hampered in their work by the confusing attachment of the same specific name to trees with quite distinct ecological properties and requirements. A judge at a dog show is not much concerned with the criteria that identify something as Canis familiaris. Such groups may go extinct , they may merge With other subgroups in the species, or they may be destined to evolve independently into full -blown species or higher taxa.
Their evolutionary significance is thus unknown and unknowable. The same, of course, could be said of groups recognized as full species, though the second alternative merging with other groups may be rare. The first is to considerspeciesasby definition the smallest units of evolution. Leaving aside the insurmountable difficulty of , my argument so far has been that.
They argue that there are many evolutionary, genealogical units within a given lineage. They suggest, therefore, that it is an error to supposethat there is any such thing as a unique basalevolutionary unit and that the particular evolutionary unit one needsto distinguish will dependon ' the kind of enquiry with which one is engaged. If there is no unique basal unit, then there is no privileged unit and, from an evolutionary point of view, no theoretical reason to pick out any particular group as the species.
Mishler and Donoghue therefore propose the second option, to " [a]pply speciesnamesat about the samelevel as we have in the past, and decouple Dupre: On theImpossibilityof a MonisticAccountof Species the basaltaxonomic unit from notions of ' basic' evolutionary units" p.
This processinvolves seeingspecieson a par with generaand higher taxathat is, as ultimately arbitrary levels of organization, chosenon a variety of 8 pragmatic grounds. Although Mishler and Donoghue seethe speciesas an ultimately arbitrary ranking criterion, they do maintain a version of the PSC and, hence, do not seeit as arbitrary from the point of view of grouping. In fact, they endorse the strong, cladistic concept of monophyly as a condition on a group constituting a species or, for that matter, a taxon at any other level.
Their " " " pluralism, however, entails that comparative biologists must not make inferencesfrom a speciesname without consulting the systematicliterature to see what patterns of variation the name purports to represent" p. But given this degreeof pluralism, and the rejection of the attempt to equate the basal taxonomic unit with any purportedly fundamental evolutionary unit, one may reasonably wonder why it is desirableto insist neverthelesson the requirementof monophyly.
I suspectthat part of the motivation for this requirementis the idea that there must be someanswer to the question what a speciesreally is. It was once, no doubt, reasonableto supposethat evolution had produced real, discrete speciesat approximately the classificatory level of the familiar Linnaeanspecies. Perhapsthis supposition was an almost inevitable consequenceof the transition from an essentialist, creationist view of nature to an evolutionary view.
Acceptanceof evolutionary theory would require that it more or less serve to explain biological phenomenaas theretofore understood. Nevertheless, a further century of development of the evolutionary perspectivehas given us a radically different picture of biological diversity. The sharpnessof differentiation between kinds and the processesby which suchdifferentiation is producedand maintainedhave proved to be highly diverse.
There is no reasonto supposethat evolution has provided any objectively discoverableand uniquely privileged classificationof the biological world. Why , then, should we continue to insist that evolution should provide a necessarycondition, namely monophyly, on any adequatebiological taxon? I can think of only three possible answers. First, it might be held that a better understandingof evolution is so overwhelmingly the most important biological task that any taxonomy should be directed at improving this understanding.
Second, it might be thought that an evolutionarily basedtaxonomy, despite its problems, would provide the best availabletaxonomy, or at least a perfectly adequatetaxonomy, for any biological project even far removed from evolutionary concerns. Or third - and this, I suspect, is the. This third motivation might be grounded either in ageneral commitment to unification as a scientific desideratumor on the fear that failure to provide a unified accountof the speciescategory will lead to massive.
The first answercan be quickly dismissed. Even as distinguishedan evolutionist as Ernst Mayr has emphasizedthe distinction between evolutionary and functional biology , the former being concernedwith questions about ultimate causation how did a trait come to exist? Following Kitcher , I prefer to distinguish these types of questionsas historical and structural. It is clear that questions about the ontogeny of the human eye, say, or about the processes by which it provides the individual with information about the environment, have little to do with questionsabout how humanscameto have the kinds of eyesthey ' have.
Of course, just noting this fact doesnt show that we need a taxonomy based specifically on structural aspectsof organisms, but it does remind us that there is more to biology than evolution. A particularly salient domain, about which I say a bit more below, is ecology. We should turn, then, to the second, and more promising, line of thought.
The fact that a great varietY of kinds of investigation takes place within biology certainly does not show that one schemeof classification, basedon phylogenetic methods, might not be adequateto all thesepurposes. To some degree, it should be acknowledged that this question is purely empirical: only the progress of biological enquiry can determine whether different overlapping schemesof classificationmay be needed.
This point needsto be stated carefully. There is no doubt at all that interesting structural or physiological properties crosscutany possiblephylo genetically basedclassification. An investigation into the mechanicsof flight , for instance, will have relevance to and may appeal to a group of organisms that includes most but not all birds, bats, and a large and miscellaneousset of insects.
In general, convergent evolution and the acquisition or loss of traits within any sizeable monophyletic group make it clear that no perfect coincidence between monophyletic groupings and the extension of physiologically interesting traits can be anticipated. Whether this calls for a distinct, nonphylogenetic systemof classificationis lessclear.
To pursuethe examplegiven, there is no particular reasonwhy the student of flight should attach any particular significance to the miscellaneousgroup of organismsthat fly. Ecology, on the other hand, raisesmore difficult issues.
Ecology, it may be said, is the microstructure of evolution. Nevertheless, it is not obvious that or even well suited to ecological evolutionarily based taxa will be ideal ' there are. There is no reasonwhy phyleti caqy diverse sets of organismsmight not be homogeneous for example as fully substitutableprey from the perspectiveof an ecologicalmodel.
Ecology will often be concernedwith the trajectory of a population without addressing competition betweendifferent subgroupswithin that population. It may, that is, abstract from distinctions within a population, perhapscorresponding to distinct lineages, which could be fundamentalin understanding the longerterm evolutionary trajectory of the population. Groups of sibling species and may prove ecologically equivalent or demographically exchangeable thus provide another exampleof a kind of distinction that may be phylogenetically significant, but ecologically irrelevant.
On the other hand it is possible that behavioral distinctions within a phyletic taxon, perpetuated by lineages of cultural descent, might provide essential distinctions from an ecological perspective. It is at least a theoretical possibility that a group of organisms might require radically diverse classification from phyletic and ecological perspectives. Perhapsa population of rats, consisting of several related species , divide into scavengers , insectivores, herbivores, and so on in ways that do not map neatly onto the division between evolutionary lineages.
Ecology may therefore, in principle at least, require either coarser or finer classificationsthan evolution, and it may need to appealto classifications that crosscutphyletic taxa. Here, it is relevant to distinguish two possible aspectsof pluralism.
One might be a taxonomic pluralist becauseone believes that different groups of organisms require different principles of classification, or one might be a pluralist becauseone thinks that the samegroup of organismsrequire classificationin different ways for different purposes. Monistic objections to the first kind of pluralism seem to me to have no merit. Taking the extreme caseof bacterial taxonomy, there seemto be very good reasonsfor doubting the possibility of a phylogenetic taxonomy.
The various mechanismsof genetic transfer that occur between bacteria suggest that their phylogenetic tree should be highly reticulated, and standardconceptsof monophyly have little application to such a situation. The significanceof bacteria as pathogens, symbionts, or vital elements of ecosystemsmake the goals of classificationquite clear in many casesregardless of theseproblemswith tracing phylogenies.
Of course, it is possible that new insights into bacterial evolution might neverthelessmake a phylo genetic taxonomy feasible. But no vast theoreticalproblem would be created if bacterial taxonomy appealedto different principles from those appropriate, say, to ornithology. The suggestionthat the useof different taxonomic principlesmight lead to serious confusion is absurd. Not every possible misunderstandingcan be forestalled.
The danger of confusion is a more plausible concern regarding the idea that the sameorganismsmight be subject to different principles of classifica tion for different biological purposes. In one sense, I am happy to agreethat this type of confusion should be avoided. It would be undesirablefor a particular , to be variously defined and to have speciesname, say Mus musculus extensions to the taxonomic varying according theory espousedby various authors.
We should aim to agree as far as possible which organisms are house mice. In the concluding section of this paper, I explain how I think such species names should be understood. If, to recall my hypothetical exampleabout rats, it proves useful to treat scavengingrats as a basickind in some ecological model, it would be misguided to insist that scavengingrats constitute a species.
Equally clearly, however, this concessionto standardized terminology does not at all require that all species names be conceived as answering to the samecriterion of what it is to be a species. The other consequenceof insisting on an unambiguousinterpretation of particular speciesnamesis that we Cannotassumea priori that the canonicaltaxonomy incorporating standard speciesnameswill be suitable for all biological purposes.
The question here is, again, an empirical one that depends ultimately on how orderly biological nature turns out to be. If it should prove to be disorderly in the relevant sense, then biology would prove to be a more complicated discipline than is sometimesassumed. But once again I cannot seethat any unavoidableconfusion need be introduced.
Someof thesechangesseementirely gratuitousfor example, changesin the names of taxa grounded in the unearthing of obscureprior namingsand in appealsto sometimesesotericrules of priority. Other changesare more theoretically based adjustments of the extent of particular taxa. Many suchtheoretically motivated changeshave beenalluded to in this paper. BSC-committed theorists will urge that discoveriesof substantial gene-flow betweenotherwise apparently good speciesshould lead us to apply one speciesnameto what were formerly consideredseveralspecies.
Phylogenetic taxonomists will want to amend the extensionsof any higher taxa that fail their favored tests for monophyly, and strict cladists will promote the breaking up of prior " species" into various smallerunits when their favored criteria for lineage splitting demand it.
II Less theoretically commi,tted taxonomists may promote the splitting or lumping of higher taxa on the basis of general principles about the degree of diversity appropriate to a particular rank. Walters gives a fascinating account of how the size of angiospermfamilies and genera can very largely be explained in terms of earlier biological lore available to Linnaeus. Considering the data collected by Willis in support of the idea that the large families- families, that is, with large number of genera- were those of greater evolutionary age, Walters arguescompellingly that the data much more persuasivelysupport the hypothesis that larger families are those that have been recognized for longer.
Very crudely, one might explain the point by arguing that the existence of a well-recognized type provides a focus to which subsequently discovered or distinguished types can be assimilated. Thus, plants of ancient symbolic significance, such as the rose and the lily , have provided the focus for some of the largest angiosperm families, Rosaceaeand Liliaceae. Walters makes the suggestive observation that even Linnaeus, recognizing the similarities between the Rosaceousfruit trees, apple, pear, quince, and medlar Malus, Pyrus, Cydonia,u and Mespilus , attempted to unite them into one genus, Pyrus.
This attempt was unsuccessful , however, presuinably becauseof the economic significanceof these , plants and modem practice has reverted to that of the seventeenthcentury. Walters comments: " Can we doubt that, if these Rosaceousfruit trees had been unknown in Europeuntil the time of Linnaeus, we would happily have accommodatedthem in a single genus!
A general feature of Walters's argument is that our taxonomic system is massively Eurocentric. The shapeof taxonomy hasbeensubstantiallydeterminedby which groups of plants were common or economicallyimportant in Europe. The crucial question, of course, is whether this bias is a matter for concern and a reasonfor expecting wholesalerevision of our taxonomic practices.
To answer this question, we must have a view as to what taxonomy is for , and we come back to the major division introduced at the beginning of this essay: should we see taxonomy as answering to some uniform theoretical project or more simply as providing a general referenceschemeto enable biologists to organize and communicatethe wealth of biological information?
The central argument of this paper is that the more we have learned about the complexity of biological diversity, the clearer it has become that anyone theoretically motivated criterion for taxonomic distinctnesswill lead to taxonomic decisionsvery far removed from the desideratafor a general referencescheme. Of course, the contingenciesof taxonomic history will no doubt have led, in many instances, to a schemethat is lessthan optimal even as a mere device for organizing biological information.
On the other hand, in. My intuition is that on this criterion taxonomic revisions will seldombe justified. Monism, Pluralism , Unity and Diversity mind in clearly conceiving and retaining in the memory the charactersof the objects in question. Plainly to the extent that taxonomic namesare undergoing constant modification, what anyone person " conceivesand retains in the memory" will be potentially incommunicableto others, and the possibility of reliably adding further information obtained from the work of others will be constantly jeopardized.
This is not to say that taxonomic revision is never justified. If a speciesis included in a genus in which it is highly anomalous , and if that speciesis much more similar to other speciesin someother genus, then the goals of organizing information will be better served by reassigningit.
It is of coursealso true that monophyletic taxa will tend to be more homogeneousthan polyphyletic taxa, and that in paraphyletic taxataxa in which some of the descendantsof the common ancestorsof aparticUlar taxon are excluded- there will be often be a case, on grounds of similarity , for including the excluded parts of the lineage.
My point is just that theseconsequences rather than monophyly itself shoUldprovide the motivation for taxonomic change, and the benefitsof such changemust be weighed carefully against the potential. In this weighing process, the presumption that taxon namesretain constant extension shoUldprobably be kept as strong as possible to maximize the ability of biologists to maintain reliable and communicableinformation.
To take perhapsthe most familiar example, it seemsto me that there is no case at all for revising the class Reptilia reptiles to include Aves birds. This move is requiredby a strict cladistic conceptof monophyly becauseit is believed that birds are descendedfrom ancestralreptiles.
We cannot exclude these avian ancestorsfrom the class that includes modem reptiles because crocodiles, still classedas reptiles, are believed to have diverged from the main reptilian lineage earlier than birds did. The fact remains, however, that most zoologists, I suppose, woUld consider crocodilesmuch more like other reptiles than either is like any bird. The attempt to convince the learned or the vulgar world that birds are a kind of reptile strikes me as worse than pointless.
It may be said that the only important claim is that Aves shoUldbe classifiedas a lower-level taxon included within Reptilia, and that this classification has nothing to do with our common usageof the terms reptileand bird. Although it is certainly the case that scientific taxonomic terms frequently differ considerably from apparently related vernacular terms, this differentiation is a sourceof potential confusion that shoUldnot be willfully exacerbated seeDupre , ch.
It is also unclearwhat advantageis to be gained from insisting on sucha revision. Similarly, experts on smaller groups of organisms will presumably be familiar with current thinking on phylogenetic relationshipswithin those groups. In conclusion, I am inclined to dissociatemyself from the strongest reading of the taxonomic pluralism I advocated earlier ; see also Kitcher In view of the limited successof theoreticalarticulations of the species category, it would seemto me best to return to a definition of the species as the basalunit in the taxonomic hierarchy, where the taxonomic hierarchy is considered as no more than the currently best and minimally revised generalpurpose referencesystem for the cataloguing of biological diversity.
This system should provide a lingua franca within which evolutionists, economists, morphologists, gardeners, wildflower enthusiasts, foresters, and so on can reliably communicatewith one another. Where special studies, such as phylogeny, require different sets of categories, it would be best to avoid using the term species the desirability of rejecting this concept is sometimesassertedby evolutionists.
Of course, such specializedusers will be free to advocate changesin taxonomic usage, but should do so only in. Although I am inclined to doubt the desirability of a extreme circumstances of pluralism overlapping taxonomies, a general taxonomy will evidently draw broadly and pluralistically on a variety of considerations.
Perhapsthe most important will be history, not an unattractive idea in a sciencein which evolutionary thought is so prominent: a goal of generaltaxonomy should be to preserve the biological knowledge accumulatedin libraries and human brains as far as possible. In addition, there would be a range of the morphological, phylogenetic, and ecological considerations that have figured in various monistic attempts to define the species. The importance of these considerationsmay vary greatly from one classof organismsto another.
My feeble monism is my recognition of the importance of such a general reference system. My recognition of the likelihood that different enquiries may need to provide their own specializedclassificationsand my tolerance of diverse inputs into the taxonomic processwill leave serious monists in no doubt as to which side I am on.
The position I am advocating provides, incidentally, a quick and possibly amicableresolution to the speciesas individuals debate. Species , I propose, are units of classificationand thereforecertainly not individuals. Lineages, on the other hand, are very plausibly best seenas individuals. Often, it may be the casethat the membersof a species or higher taxon are identical to the constituents of a lineage, but of course this coincidence does not make the speciesa lineage.
And it is doubtful whether all species, or certainly all higher taxa, are so commensurablewith lineages. Resistanceto or even outrage at the kind of position I am advocating may derive from the feeling that I am flying in the face of Darwin. Darwin, after all, wrote a well-known book about the origin of species,and he was writing about a real biological process, not a naming convention.
Monism,Pluralism , Unity andDiversity species and had in mind kinds , not things. Arguably , the tension between these two usages is at the root of the great philosophical perplexity that the concept of species has generated in this century. In arguing for reversion to the earlier usage of the term species , I am at least honoring conventions of priority. What I am proposing , however , is not much like a Linnaean taxon omy either.
As many have observed , Darwin forced us to give up any traditionally essentialist interpretation of taxonomic categories and even any objectively determinate taxonomy. But almost a century and a half of biological work in the Darwinian paradigm have also shown us that evolution does not reliably produce units of biological organization well - suited to serve the classificatory purposes for which the concept of species was originally introduced , so perhaps rather than a reversion to Unnaeus , it would be better to see my proposal as a quasi- Hegelian synthesis.
At any rate, if I seem to have been implying that Darwin may have been responsible for introducing some confusion into biology , I am sure no one will take this as more than a peccadillo in relation to his Unquestion ably positive contributions. NOTES 1. It is not entirely clearhow to makethis idea precise. Obviously, not every organismfounds a. A natural idea is that every organism in lineage, unlessevery organismis to constitute a species any way genetically distinct from its parent should found a new lineage.
Given, however, the possibility of the samepoint mutation occurring more than once, it could turn out that a set of genetically identical organismsmight constitute two or more distinct species. The proposal also leads to the surprising conclusion that the vast majority of speciesare asexual.
As Hull notes, this conclusionmay mitigate the well-known difficulty in explaining the origin of sex by showing that sexual reproduction is a much rarer phenomenonthan is often ' supposed , I should also mention that Hull s proposal is made. It appearsthat the sameis probably true for somekinds of flowering plants seeNiklas , 74 fE.
This claim is perhapsless true now than it was twenty years ago. An influential evolutionary classificationof bacteria was proposed by Woese ; see also Pace On the other hand, Gy Uenbergand others aim explicitly to producea classificationthat is optimal from an information-theoretic perspective, a goal that there is no reasonto supposewould be met by any imaginable phylogenetic scheme. Seealso Vandammeand others for a related proposal.
Gordon , for instance, Collpopulations in feral mice was an increasing reports that the genotypic diversity of Escherichia function of the age of the mouse, indicating the development of distinct clones during the lifetime of the n:' use. The situation is still worse in view of the partially reticulate phylogeny consequenton genetic exchangebetweenbacteria.
An extreme statementof this optimistic view can be found in Ruse , : There are different ways of breaking organisms into groups and they coincide! The genetic speciesis the morphological speciesis the reproductively isolated speciesis the group with common " ancestors. The consequencehas been an excessivemultiplication of supposedspecies. The same species is describedby Schauer , as aggregate, variable " with very numerous miaospecies.
More optimistically, The Oxford Book of Wildjlowm " Nicholson, Ary , and Gregory statesthat [t ]here are severalhundred speciesand hybrids " in the Rubusgroup, and only an expert can identify all of them. SeeSober for a very clear exposition of this distinction. Although the debatehere is a fundamentalone, it is not of central concernto my essay.
For further elaboration, seeMishler and Brandon For more generalargumentsagainst any fundamentaldistinction between speciesand higher taxa. Somemore realistic exampleshave beendiscussedby Kitcher For referencesto bacterialtaxonomy and brief discussion , seenote 3. De Queiroz and Gauthier , claim that taxonomic changesthey advocate will promote constancy of meaning, or definition, for taxa.
Mammalia, for example, should be defined as the set of descendantsof the most recent common ancestor i. The extensionof sucha term, however, will be constantly revisablein the light of changesin opinion about the details of evolutionary history. From the point of view of the consmnerof taxonomy, at least, I suggest that constancy of extension is surely more valuablethan constancyof definition. Subsequentto Walters paper, the quince appearsto have been reconceivedas Chatnomtles though not unanimouslyaccording to the few sourcesI consulted on this matter.
This reconception effects a conjunction with the ornamentalflowering quinces. One might speculatethat the increasingobscurity of the quinceas a fruit might have exposedit to this annexation, whim one doubts could have happenedto the apple. Bentham , G. Hooker Handbook of theBritishFlorR Rendle.
Ashford , Kent: L. Notes Davis, P. Gauthier Phylogenyasa centralprinciplein taxonomy System RticZooiog 39 neticdefinitionsof taxonnames , ,v de Queiroz, K. Towarda phylogeneticsystemof biologicalnomenclature tmdEvolution. Trends in Ecology 9, Monism , Pluralism Unity and Diversity : Metaphysical. Cambridge of things foundations of thedisunityof science Dupre, J.
Are whalesfish? L Medin andS. Atran, eds. Science , Ehrlich , P. R, andP. Raven Differentiationof populations Reprintedin Ereshefsky 58, , M. Species , highertaxa , andthe unitsof evolution. Philosophy Ereshefsky of Science Cambridge , M. Theunitsof evoluh , Mass. Bacteri , G. Someremarkson the theoreticalaspects Floodgate 26, Species concepts Metaphysics Gilmour,J: S.
L Thedevelopment of taxonomictheorysince Nature, Collpopulationsin feralmice. Thegeneticstructureof Escherichia. Schindler , andM. Verlaan Classi Gyllenberg , H. Gyllenberg , T. Koski, T. Lund ficationof Enterobacteriacea. British Hull, D. Theeffectof essentialism 15, , and16, 1- Journal for thePhilosophy of Science 'on. Hull, D. Themetaphysics of evoluh. Philosophy Kitcher,P. Species 51, An essay , editedby P. Mayr, E. Causeandeffectin biology. Science : Scientificprogressandphilosophical termi.
The ontologicalstatusof species Mayr, E. A system , 5th ed. London , SonandBourn of logic : A casefor pluralism. Systemah 'c Mishler, B. Donoghue Species concepts 31, Zoology Mishler, B. Brandon Individuality , pluralism , and the biologicalspecies and 2 Oxford: Oxford Nicholson , B.
Ary, andM. Gregory TheO:rfordbookof wildflowers. Chicago : Universityof ChicagoPress. Niklas, K. Science , Pace. R A molecular Ruse : Naturalkinds, individuals , M. Biologicalspecies , or what? BritishJournalfor the 38, Afieldguideto thewildflowersof BritRinRndEurope.
Pankhurst : Collins. London Sober , E. Uoyd andE. Kelier, eds. Cambridge : HarvardUniversityPress. Sneath , P. Sokal NumeritRlt RXonomy. SanFrancisco : W. Stebbins : Semantics andactualsituations , G. Biology RndPhilosophy 2, concepts The meaningof speciesand speciation : A geneticperspective. Temple Otte andJ. A Endier Rndits consequences. Sunder , eds. Reprinted land, Mass. Vandamme , P. Pot, M. Gillis, P. De Vos, K. Kersters taxon, andJ. Swings Polyphasic a consensus to bacterial.
Rl , Reoiero 60 Ecologicalspecies , multispecies , oaks. Reprintedin Ereshefsky Walters. NewPhytologist , S. Theshapingof angiosperm 60, Geneva : Conservatoire et JardinBotaniquede la of pltmts Ville. Woese evolution. Microbiologi CRI Review 51, Hull In the nineteenth century, one of the hot topics of debate was the plurality of worlds. Did God create a single Earth inhabited by all and only those souls that Jesusgave the opportunity to be savedfrom eternal damnation, or did He createmillions of worlds inhabited by just as many morally responsible beings?
On the first alternative, God would appearto be as profligate as the most extravagant wastrel. He createdmillions of nebulae, each containing just as many stars, eachof which might have planets circling it in stately regularity, but on only one of these planets circling a single star did He breath soul into a single species. What a waste. But if we assumethat God is the ProtestantGod of " wastenot , want not," surely He would not have let so many opportunities slip through his fingers for creating subjectsto worship him.
Not only did Jesuscome down to Earth to be sacrificedfor our sins, but apparently he also repeatedthis ritual in world after world after world for a ' history of this controversy, seeDick s Plurality of Worlds. No less a figure than William Whewell entered into this debate- on the side of the monists.
For fear of damaging his hard-eamed reputation as a sober seeker after truth , Whewell anonymously published The Plurality of Worlds To those who complained that God and hence nature did nothing in vain, Whewell cited all the waste that was already so apparentin this world: We reply, that to work in vain, in the senseof producing meansof life which are not used, embryos which are never vivified , germs which are not developed ; is so far from being contrary to the usualproceedingsof nature, that it is an operation which is consistently going on, in every part of nature.
Of the vegetable seedswhich are produced, what an infinitely small proportion ever grow into plants! Of animal ova, how exceedinglyfew becomeanimals, in proportion to those that do not; and that are wasted, if this be waste! God creatednumerousdifferent species , but did He create a singlesori of species or many differentsoris of species7Each and every organism belongs to one speciesand one speciesonly , but are all these speciesof the samesort7 Or possibly, does anyone organism belong to many different sorts of species7 Thesequestionsare also central to the presentcontroversy between monists and pluralists with respect to species.
In Whewell' s day, the plurality of worlds was a very open question, but today the party line on pluralism conflicts with respectto there being a party line on species. As Sterelny chapter in 5 this volume remarks, "Evolutionary theory has moved close to a consensus in seeingspeciesas historical individuals Ghiselin , Hull ," but how can consensusexist with respectto the ontological statusof species if pluralism is the party line among philosophers of science, especiallyphilosophers of biology?
Everyone seemsto feel obligated to espousethe position held by all thoughtful scholars- a nuancedpluralism, as distinct from any crude, simplistic monism. One problem unfortunately characteristic of such contrasts as monism versus pluralism is that the apparent differencesbetween them tend to disappear under analysis. Numerous sensesof monismblend imperceptibly into just as many sensesof pluralism.
For example, Ereshefsky , concludes his discussion of " eliminative pluralism" with the observation that " Some may view eliminative pluralism asjust a complicatedform of monism. If that is the case, then the argumentsof this paper have been successful. When pushed, most authors retreat to some platitudinous middle ground.
In this respect, the issue of pluralism mirrors the conflicts over nature nurture and genetic determinism. Does anyone think that genes are sufficient for anything? If this view is what genetic determinism entails, then genetic determinists are most noteworthy for their nonexistence. In the first section of this chapter, I discusssome very general issueswith respect to pluralism before turning to one example - biological species. I take a look at the connection between the monism versus pluralism dispute and a the contrast between realism and antirealism, b prerequisites for communication, and c reflexivity.
Philosophers of sciencehave produced a variety of analysesof the notion of causation. Someof the cruder, simplistic analysesallow us to reject certain claimsmade by scientists who find the HIV hypotheses a conspiracy, not to mention scientistsworking for the Tobacco Institute who argue that smoking does not causelung canceror any other diseasefor that matter. However, these scientistsare able to hide behind the smoke screensgenerated " " by more sophisticated,pluralist analysesof cause producedby equally sophisticatedphilosophers.
Causalsituations are so various and complicated that nothing can be identified as causing anything, just as the biological world is so varied and complicatedthat no one analysisof " species" will do. Instead, indefinitely many speciesconceptsare neededfor indefinitely many contexts.
The great danger of pluralism is " anything goes. Monism , Pluralism , Unity andDiversity evaluating these evaluative criteria for various speciesdeAnitions. My conclusion is that if we retain the traditional organizational hierarchy of genes, cells, organisms, colonies, demes, species , and so on, any and all speciesdefinitions appearinadequate.
One possibleway for a monist to avoid this conclusion is to abandon, not the traditional Linnaean hierarchy Ereshefsky , 11 in this volume but the. Of the four possiblecombinationsof thesephilosophicalpositions, two seem , andpluralismcombinedwith quite natural: monismcombinedwith realism antirealism. Monistsarguethat scientistsshouldstrive to find the bestway to divideup the world andthat sucha bestway doesexist, eventhoughwe whetheror not we have may neverknow for sure whateverthat means found it.
Yes, scientistsarefallible. Yes, conceptualrevolutionsdo occurin science , revolutionsthat reqUireus to startnot all over again, but at leasta few stepsback. Giventheseassumptions , the goal of findinga single, maximally informativeconceptualization of natureseemsboth desirableandreasonable. If one is going to be flat-footedand simpleminded with respectto onephilosophicalposition, why not two? Holsinger interpretsSober [a]asa monist-realist. The natureof these differences everemerge , but rarelydoesconsensus , andwhen surelychanges " the" world canbe it does, it is likely to be short-lived.
How come? Because charaderizedin indefinitelymany ways, dependingon differencesin perspectives , worldviews, paradigms , and what haveyou. Eventhoughnot all of thesewaysareequallyplausible , acceptable , or promising , no oneway is clearlypreferableto all othersonceandfor all. Onemustkeepan openmind. If one is going to be sophisticated and nuancedwith respedto one philonot two? Stanford  portrayshimselfasbeinga sophicalposition, why antirealist.
It would seema bit strangeto arguethat one and only one way existsto divide up the world, but that the groupsof naturalphenomena arenot "real. Of course , realcanbe definedin sucha way that nothing couldpossiblybe real, just asphilosophers havedefinedknowso that no one ever knowsanythingand law so that no generalizations ever countas la. A combinationof pluralismandrealismseemsequallypeculiar but extreme seeDupreandKitchera.
Theworld canbe dividedup into kinds in numerousdifferentways, and the resultsareall equallyreal! Or one might get incommensurable , but the sort of holistic semanticsthat generatesincommensurability again seemsa high price to pay. For a discussionof realism and pluralism with respect to the units of selection controversy, see Sober b; Sterelny and Kitcher ; Kitcher, Sterelny, and Waters ; Waters ; Soberand Wilson ; Shanahan In fact, in the face of imperfect knowledge, vaguenessmay be necessaryfor communication Rosenberg Again, I find it difficult to tell, but even the most rabid deconstructivist shies away from anything- literally anything- goes.
Even they seemto assumethat they are saying something or trying to say. Possibly, they are not saying something with varying degrees of success one and only one thing with absolute clarity, but not all interpretations are equally acceptable- Emily Dickinson as a Marxist feminist. Perhapsour intended meaning is neither patent nor all there is to the story, but at the very least I have been taught that we should all aim to present our views as clearly and unambiguously as possible, and I see no reason to give up the ghost at this late date.
PerhapsI can be a selective pluralist about a halfdozen conceptsat a time, but I cannot treat all of languagepluralistically all at once, not if I want to say something, not if I want other human beings to understandme.
These sociologists tried a variety of ways to extricate " " themselvesfrom this tension in their position. Monism , Pluralism , Unity andDiversity and b. However, Collins also acknowledges that even sociologists periodically need to step back from their own work and treat it as problematic as well. The knowledge claims made by sociologists are also socially constructed.
Becausesociologists are themselvesscientists, reflexivity poses especially poignant problems for them, but reflexivity can also be brought to bear on contrasts between object-level and metalevel positions. Philosophers are not scientists. As philosophers, we do not do science. We comment on it. Of course, someonewho is officially a philosopher can join in the scientific ' enterprise, and vice versa. Thus, a certain tension exists in Hempels position that data play crucial roles in science, but no role whatsoever in his logical empiricist analysisof science.
Just becausescientistsclaim to explain ' phenomenain ways different from Hempel s covering-law model does not meanhis covering-law model of scientific explanation is false. If no scientists ever explained anything by deducing it from laws of nature and statements ' of particular circumstances , Hempel s covering-law analysis of explanation still could count as a totally adequateanalysisof scientificexplanation! Parallel observationshold forplural ists.
With respectto science so pluralists claim- serious, respectablealternative exist for every issue, but when one steps back to positions always view philosophy of science, one and only one position is acceptable:pluralism. John Maynard Smith raisesprecisely this objection in his review of Soberand Wilson As in the caseof Hempel's logical empiricist analysisof science, pluralists are not contradicting themselves in holding such different positions on scienceand philosophy, but it is a bit difficult to swallow their position.
If one can be a monist with respect to - of all things- philosophical debates, one can certainly on occasionthink that monism is justified in science. If one and only one position is warranted with respect to the monism-pluralism dispute, then certainly one and only one position is warranted with respect to the evolutionism-creationismdispute. Possibly one and only one position is warranted with respectto the speciesproblem. If not , I am missingsomething of massivesignificance.
As I have argued above, philosophers find pluralism extremely attractive in science, -much more so than in philosophy. At least sometimes, scientiststhink that they have the right answer to a particular question. What would sciencebe like in the absenceof such convictions? Picture hundredsof scientists, eachbeing terribly considerateof eachother' s hypotheses: "You think that selection occurs only at the level of the genetic material? That may be so, but in addition, individual organismsare the main target of selection.
A preference for monism and pluralism waxes and wanes as various groups gain and lose power. Right now, advocatesof developmental systems theory are trying to supplant the current gene-centered world view Moss , Griffiths and Gray None too surprisingly, these developmentalists are urging pluralism. In general, groups who hold minority opinions at a particular time find pluralism to be the correct philosophical view, whereasthe groups in power are not nearly so attracted to it.
During the heyday of the biological speciesconcept, Mayr saw no reason to give ground to his opponents. He insisted that there are basic units in the evolutionary process, that theseunits are delineatedin terms of reproductive isolation , and that making these units coincide with the basic units of classification is both possible and desirible. I predict that if and when developmentalistssee their views prevailing, they will ceasetheir pleas for pluralism and becomestaunchmonists.
Pluralismlooks good to outsiders regardlessof whether they belong to different disciplines e. At times, they seemto help; at other times, they - philosophy seemto obfuscateunderstanding. The notion of causecan serve as anillus trative example. Monism , Pluralism , Unity andDiversity closed down. Or perhapsan inhalant termed popperswas the cause. Or possibly some infectious agent was responsible. Rather rapidly, the evidence indicated that the most likely explanationwas also the correct explanationa virus transmitted primarily by infected needlesand sexual intercourse.
At the time that scientiststurned their attention to the AIDS virus in and , the evidencewas far from -conclusive. In a very real senseof the term, " " they might have beenmistaken. However, little by little a consensusemerged that AIDS is a contagious disease , and the causative agent is a virus eventually termed the human virus or HIV for short Blattner, Gallo, and Temin He argued that AIDS is " " not one disease , but at least four.
Instead, the useof drugs, suchas poppers, are the real cause. One important feature of scienceis persistence in the face of considerableopposition. On occasion, scientistswho were thought to be in the lunatic fringe in their own day eventually are vindicated.
Continuing to doubt it today is quite another matter Duesberg However, Duesberg usesall sorts of speciousarguments about causationto salvagehis position. It needshosts to invade. Without people, the various strains of virus that can infed only human beings would be in real trouble.
In addition, if no one had ever isolated the blood- clotting factor in people, hemophiliacs would not have been put at greater risk than other people. If no one ever sharedneedles, if everyone used virus-impermeablerubbers whenever they , we would never have had an AIDS epidemic engaged in sex, etcetera, etcetera. I And if God were truly good, etceter, etcetera. In addition, contagious diseasesare commonly defined in terms of the presenceof the causative agent.
In order to have tuberculosis, you must be infected with the tuberculosis - by definition. But it is not sufficient. In order bacterium.
PARAGRAPHIt also draws on a to the seminal work of pluralism; species realism; historical dimensions; cognitive underpinnings; and practical import. Books Journals Reference Works Topics. Life Finds a Way. Plant Evolution in the Mediterranean. Richardson, Kim Sterelny, Robert A. About this book Customer reviews from anthropology, botany, developmental psychology, science, protozoology, and zoology. About this book New approach broader range of disciplines and brings neglected cognitive, anthropological, and the impact of his work was felt beyond the natural. Click to have a closer.The concept of species has played a central role in both evolutionary biology and the philosophy of biology. This book is integrative and analytical, centring on issues of general significance such as pluralism and realism about species. PDF | On Jan 1, , Robert A. Wilson published Species: New Interdisciplinary Essays | Find, read and cite all the research you need on. alsa.collegegradesbooster.com: Species: New Interdisciplinary Essays (): Wilson, Robert A.: Books.