last chance saloons for natural kind realism anjan ... · traditionally, accounts of natural kinds...

Last Chance Saloons for Natural Kind Realism

Anjan Chakravartty University of Miami

Abstract Traditionally,accountsofnaturalkindshaverunthegamutfromstronglyconventionalisttostronglyrealistviews.Recently,however,therehasbeenasignificantshifttowardmoreconventionalist-soundingpositions,even(perhapsespecially)amongphilosophersinterestedinscientificclassification.Theimpetusforthisisatrendtowardmakinganthropocentricfeaturesofcategories,namely,capacitiestofacilitatehumanepistemic(andother)interestsviainductiveinference,centraltoanaccountofkinds.Iarguethattakingthesefeaturesseriouslyisbothdefensibleandcompatiblewithconventionalism,butnotcompatiblewithatraditionalrealismaboutkindsspecifically.Moreover,hopesofachievingcompatibilitybyrevisingandextendingkindrealism–intowhatIcall‘hyperrealism’–faceaninsuperabledilemma.Thenewsforrealistsisnotallbad,however:thoughkindrealismprovesuntenable,closelyassociatedrealismsunderlyingtheobjectivityofkinddiscoursemaybeviablenonetheless.Keywords naturalkinds•conventionalism•constructivism•deflationism•realism•hyperrealism•naturalness•scientificrealism1. A traditional framework for thinking about natural kinds

Somuchhasbeensaidabouttheideaofnaturalkinds–theancientnotionthattheworldis

inhabitedbynaturalcategoriesofthings–thatonemightnowexpectthebroadoutlineofcoherent

versionsofthisideatobelargelytransparent.Iwillargueinwhatfollows,however,thatthisisnot

entirelyso,atleastconcerningthemorespecificideaofrealismaboutnaturalkinds.Itisarguable

thattheideaofnaturalkindrealismhasbecomelesstransparentinrecentdecades.Myaiminthis

paperistountanglewhatItaketobesomeconfusionhereand,intheprocess,describeandassess

whatprospectsremainforrealismaboutkindsspecifically,thatis,forrealismaboutputativekind

categoriesthemselves.Discussionsofrealisminthiscontexthavebeensusceptibletoconfusionin

partbecausecontrastingviewsofkindsalltendtoinvolverealismaboutsomething,andthis

somethingisoftenconflated,inappropriately,withkindcategories,orsoIwillsuggest.

Asafirstpass,thenotionofnaturalkindsisusuallyspelledoutintermsofgroupsofentities

(e.g.,objects,events,processes)whosemembershavesomepropertyorpropertiesincommon.

Differentviewsofkindselaboratethisbasicideainanumberofdifferentways,seekingtoanswer

differentquestionsandwithdifferentconceptionsoftherelevanttermsofart.Withthisinmind,

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andsoasnottogetlostinthethicketbeforewedigin,letmebeginbyrestrictingthefocusand

clarifyingmyownuseofsomekeyterminology.Theprimaryconnotationsofrealismare

compatible(Ibelieve)withdifferentpositionsregardingmanyotherdebatesaboutkinds.For

example,giventhefirstpassatkindssketchedaboveintermsofsharedproperties:someholdthat

thesepropertiesareintrinsic,othersthattheymayalsobeextrinsic;somethinkthattheycomprise

essences(i.e.,theyareindividuallynecessaryandjointlysufficientforkindhood),othersthat

variableclustersofpropertiessuffice;somedisputewhetherkindsareparticularsorsetsof

particularsoruniversals(andifuniversals,whethersimpleorcomplexorboth).Leavingallofthese

detailstooneside,myfocushereisthebigger-picture,foundationalquestionofwhatitmeanstobe

arealistaboutkinds,andwhetherthetraditionalconceptionofthisviewisdefensible.

Tacklingthisfoundationalquestionrequiresanengagementwithbothmetaphysicaland

epistemologicalissues,whichinturnrequiressometerminologicalclarification.Traditionallyand

generically,‘realism’denotesabeliefinthemind-independentexistenceofsomething.Adetailed

treatmentofthisideaexceedsmyaimshere,butaroughcharacterizationwillserveforpresent

purposes:tosaythatsomethingexistsmindindependentlyistosaythatitsexistencedoesnot

dependonitsbeingthoughttoexist.Onthisunderstanding,someofwhatarecommonlylabelled

‘socialkinds’or‘humankinds’(e.g.,groupswhosememberssharesocialorpsychological

properties)mightwellseem,primafacie,toexistmindindependently,thoughnotall(e.g.,money,

theexistenceofwhichquamoneydependsonitsbeingconceivedassuch).Similarly,atleastsome

ofwhatarecommonlyregardedasartifacts–birds’nests,geneticallymodifiedorganisms,

especiallyheavyelements,novelchemicalcompounds,etc.–whosecomingintoexistencemay

dependonthoughtintheformofintentionsandactsofcreation,mightwellseemtoexistinamind-

independentwayoncecreated.Thereismuchtodebateinconfrontingfiner-grainedcontroversies

engenderedbythesesortsofexamples,withconsequencesforfiner-grainedelaborationsofmind

independence,butthebasicideaofexistingindependentlyofbeingthoughttoexistisallthatwill

beneededhere.Realismaboutkindsisthustheviewthatkindsthemselves–therelevant

categories1–existindependentlyofbeingthoughttoexist.

Granted,thereareotherwaysonemightproceed,butalsosignificantreasonstodoubtthat

theyarecompelling.Forinstance,takingissuewithmycharacterizationofmind-independent

existence,onemightregardasminddependentanykindinvolvinghumanmindsorthoughts

1Cf.Bird&Tobin(2018),whoclarifythenotionofrealismaboutnaturalkindsintermsoftheexistenceofkindsspecificallyas‘aspecialsortofentityinourontology’.

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simpliciter.2However,thisseemsclearlytomistaketherelevantsenseofmindindependence.The

existenceofmentalproperties,forexample,maydependontheexistenceofminds,butpresumably,

giventhatmindsexist,theexistenceofmanyormostmentalproperties(whatevertheymaybe)

doesnotdependonwhetherorhowwethinkaboutthem.Itisthelattersenseofmind

independencethatisrelevanttorealism,andevenhumanmindsmayhavemind-independent

propertiesinthissense.Primafacie,kindsdefinedintermsofsuchpropertieswouldthusseem

appropriatecandidates,atleast,forrealismasitistraditionallyconceived.Inanycase,noneofthe

argumentstofollowwillhangonanymoreprecisestipulationsregardingmindindependence,or

theoutcomesoffiner-graineddebatesinvolvingsuchstipulations.

WhatIhavejustidentifiedasatraditionalunderstandingofrealismimmediatelygives

shapetoatraditionalframeworkforthinkingaboutkindrealism,anditsdenial.Themind-

dependentexistenceofsomethingentailsthatitsbeingthoughttoexistisanecessaryconditionof

itsexistence;inotherwords,therelevantthinkingisconstitutiveoftheexistenceofthekind.Letus

callviewsthattakenaturalkindstoexistminddependentlythusconstruedconventionalist.

Historically,viewsofnaturalkindsmaybeseenaspopulatingaspectrumfromstrongly

conventionalistviewsatoneextreme,tostronglyrealistviewsattheother.Theterm‘subjective’is

oftenappliedtokindsinconnectionwithconventionalismand‘objective’usedlikewisein

connectionwithrealism.Iwillsimplytakethesetermstobesynonymousfor‘minddependent’and

‘mindindependent’,respectively.

Asafinalclarification,itisworthnotingthattheterm‘natural’in‘naturalkind’isitself

ambiguous.Inmuchwritingaboutkinds,‘natural’istakentobeellipticalfor‘mindindependent’or

‘objective’,andthusasindicativeofsomethingamenabletorealism.Ontheotherhand,itisnot

unusualforconventionaliststousetheterm‘naturalkind’,notinconjunctionwithrealism

exclusively,butmerelyasanameforthosecategorieswhosestatusasmindindependentor

dependentissubjecttophilosophicalconsideration.Inthisuse,theterm‘natural’carriesno

implicationofbeingconducivetorealism.Itismerelyalabelforthetopicunderdiscussion–the

categoriesweusetoclassify,taxonomize,andsoon.Whileitisgenerallyclearfromthecontext

whichoftheseusesisintended,toavoidanyconfusionIwillsimplyusetheterm‘kind’henceforth,

andconsiderthenotionofnaturalnessseparatelywhenitarises.

Insection2,Iexaminetheideathatepistemicsuccess–morespecifically,thesuccessof

variousformsofinductiveinference–isproperly,intimatelyconnectedtotheorizingaboutkinds.I

2SeeEreshefsky2018,pp.845-846,fordiscussionandreferences.Cf.Slater2013,p.22;Franklin-Hall2015,pp.927-928;andKhalidi2013,sections4.5and6.5.

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willsuggestthatthisissoforbothconventionalismandrealism,thoughfordifferentreasons,and

defendtheideathatinductivesuccessisageneralmarkerofgenuinekindhoodagainstsomerecent

objections.Insection3,Iscrutinizethenatureofthisconnectionmorepreciselyfor

conventionalism,settingthestageforaparallelexercisewithrespecttorealisminsection4.Iargue

thatbyfocusingattentionontheconnectionbetweenkindsandinductionandintakingitseriously,

anuntenableaspectofearlierapproachestorealismisilluminated.Theupshotofthisforrealism

hasbeenmuddled:viewsthatcallthemselves‘realist’butnotinthemanneroftraditionalrealism,

leavingthestatusofrealismaboutkindsspecificallysomewhatambiguous,orviewsthatsimply

lapseintoconventionalism.OnemayattempttorevisetraditionalrealisminfavorofwhatIwillcall

‘hyperrealism’,discussedinsection5.Hyperrealism,however,facesafataldilemmaconcerning

naturalness.Insection6Iconcludebyreflectingonwherethisleavestheprospectofrealism.

2. Inductive virtues as indicators of genuine kindhood

Whatisthemotivationforentertainingthepossibilitythattherearekindsinthefirstplace?

Differentaccountsofferdifferingmotivations,butonecommonlycitedelementistheideaof

accountingfortheepistemicsuccessthatinvestigatingandreasoningabouttheworldintermsof

certaincategoriesaffords.3Thisiswhy,asnotedearlier,thequestionofkindrealismisonewhose

assessmentinvolvesbothmetaphysicalandepistemologicalissues.Themetaphysicaldimensionis

apparentimmediatelyintheoppositionbetweenrealismandconventionalismandthe

correspondingtask,onanygivenversionoftheseapproaches,ofspellingouthowexactlyit

incorporatesthenotionofmindindependenceordependence.Theepistemologicaldimensionis

lesstransparentbutneverthelessinextricable.Thefactthatkindsarepositedtoaccountfor

epistemicsuccessultimatelyplacesconstraintsonwhatkindsaretakentobe,becausethe

epistemicsuccessthatsomecategoriesaffordandothersdonotamountstoarepositoryof

empiricaldataforthinkingaboutthenatureofkinds.

Asananalogy,considerhowscientificrealismisgenerallyheldtohavebothmetaphysical

andepistemologicaldimensions–themetaphysicaldimensionconcerningthemind-independent

existenceofvariousthingsdescribedbyourbestscientifictheories(oftencouchedinothersterms,

suchastheapproximatetruthorsuccessfulreferenceofthosedescriptions),andthe

3Thisassertsthecentralityofepistemicinterestsbutdoesnotpreclude,ofcourse,therelevanceandimportanceofnon-epistemicintereststothinkingaboutkinds.Oftentheformerarethemeansbywhichwehopetoservethelatter,aswellaspracticalandpragmaticinterests.

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epistemologicaldimensionimplicitintheappealto‘ourbesttheories’.Ourbesttheories,scientific

realistsandantirealistsagree,areourmostsuccessfultheories:thosethataffordthemostaccurate

andreliablepredictions,retrodictions,generalizations,andexplanations.Twopointsarehelpful

hereintheanalogytokinds.First,alloftheactivitiesassociatedwithsuccessfulsciencelistedabove

areoutputsof,orunderwrittenby,inductivereasoning.Second,bothrealistsandantirealistsabout

sciencetakethisasadatum;theiraccountsofwhatweshouldbelieveinscientificcontextscanbe

viewedaswaysofparsingandexplainingthisinductivesuccess.Dataregardingtherelativesuccess

ofdifferenttheoriesisaninputforbothrealistandantirealisttheorizingaboutscience,resultingin

differentoutputs.

Realismandconventionalismaboutkindsparallelthesefeaturesofrealismandantirealism

aboutscience.Theinductivesuccessaffordedbycertaincategoriesisadatumthatonemaywishto

explain.Indebatesbetweenscientificrealistsandantirealists,theformersometimesthinkofthisin

termsofa‘miracleargument’,ormoregenerallyassomethingakintoatranscendentalargument.

Inotherwords,somescientificrealistsarguethatthebestexplanationofthesuccessofatheory–

perhapstheonlygoodornon-miraculousexplanation,ifnotquiteanecessaryprecondition–isthe

mind-independentexistenceofwhateverisputativelydescribedbythattheory.Scientific

antirealistscounterwithrivalaccountsofsuccess.Similarlyandtraditionally,realistsaboutkinds

explaininductivesuccessintermsofourhavingcarved,inthemannerofanepistemicsamurai,at

nature’sownjoints,toinvokethePlatonicmetaphor.Conventionalistsaboutkindsexplainsuccess

differently,intermsofcategoriesthataremerelyusefulinconnectionwithourvariousinductive

purposes.Intheirdifferentways,bothtakeinductivesuccesstobeastandardmarkerorindicator

ofgenuinekindhood(butseefootnote3).Takingsuccessinhumanepistemicpursuitsseriouslyis

thusrelevanttotheorizingaboutkindswhateverpositiononetakesinthetraditionalrangeof

positionsmappedoutbyconventionalismandrealism.

Ihavebelaboredthispointaboutthecentralroleofinductivesuccessintheorizingabout

kindsbecauseitiscrucialtowhatfollows,buttheideathatthereissomesuchconnectionhasnot

generallybeencontroversial.Exploringconceptuallinkagesbetweenkindsandinductionisa

themethatappearsfromantiquitytothepresent(seeHacking2007forahistoricalsweep).Inthe

immediatebackgroundofcontemporarydiscussions,HilaryKornblith(1993,p.7)contendedthat

‘Thecausalstructureoftheworldasexhibitedinnaturalkinds…providesthenaturalgroundof

inductiveinference’,andRichardBoyd(1999,p.146)suggestedthat‘Itisatruismthatthe

philosophicaltheoryofnaturalkindsisabouthowclassificatoryschemescometocontributetothe

epistemicreliabilityofinductiveandexplanatorypractices.’Morerecently,P.D.Magnus(2012,

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chapter1)constructsanimpressivelistofelevendifferentideasassociatedwithkindshistorically,

butthemostwidelyacceptedone–andtheonlyone(apartfromtwomorecontroversialideas

motivatinghisownparticularview)hefindstobesufficientlywellmotivatedtoinformour

theorizingaboutthem–is‘theinductionassumption’.4

Allofthissaid,thereisatleastsomerecentresistancetotheinductionassumptionbasedon

examiningourmodernconceptionofwhatwasconsidered,inancienttimes,anexemplarycaseof

kinds:biologicaltaxa.MarcEreshefskyandThomasReydon(2015,pp.977-8)associatetheclaim

thatkindsaregroupsofthingsthatsupportinductiveinferenceswiththeideathatmembersofa

kindshareasignificantnumberofrelevantproperties(Iwillreturntothisideainsection5),which

thenunderwritesinductivepracticessuchaspredictionandgeneralization.Thethought,

presumably,isthatitisbecauseofthissubstantialsharingthatweareoftensuccessfulinforming

expectationsaboutonememberofakindonthebasisofknowledgeofanother.However,twoofthe

mostprominentapproachestoclassifyingtaxaincontemporarybiology–Cladismand

EvolutionaryTaxonomy–regardthemashistoricallineagesoforganisms,eachdescendedfroma

commonancestor,andoverlongenoughperiodsoftime,thepropertiesoforganismsatdifferent

timeslicesalongalineagemaydiffersignificantly.

Furthermore,tomakemattersworsefortheinductivist,ontheseundeniablyimportant

approachestobiologicaltaxonomy,itisoftenthecasethatwhenapopulationoforganisms

branchesofffromitsparentpopulation–theymightbeseparated,forexample,asaresultofa

weathereventorvolcanicactivity–theorganismsintheparentspeciesandthenewspecieswill

shareasubstantialnumberofbiologicallyrelevantproperties.Andthoughtheyhavenowbeenre-

classifiedastwodifferentspecies,thissubstantialsharingofpropertiesmaycontinuefora

significantperiodoftime.FromthisEreshefskyandReydon(p.978,footnote4)concludethatnot

allscientificclassificationislinkedtoinduction,asopposedtodifferentaims.Moreover,‘tolimit

naturalkindstothosekindsthatfeatureinsuccessfulinferentialpractices…isanaprioriapproach

tonaturalkindsthatdoesnotdojusticetotheepistemicpracticesofscientists’.

Thisskepticismaboutinduction,however,isunfoundedonbothcounts.Regardingthefirst

charge,thatinductivesuccessisimmaterialtotheorizingaboutkindsinatleastsomecases,crucial

weighthereisbornebythesuggestionthat‘differentaims’maybeservedinstead.Inthecaseof

CladismandEvolutionaryTaxonomy,‘theaim…istoclassifydistinctbranchesontheTreeofLife’

4Magnus2012,p.8:‘Acentralassumptionaboutnaturalkinds–thecanonicalassumption–isthatyoucanmakeinductiveinferencesaboutthem.…Thisissharedsowidelythatanyreasonableaccountofnaturalkindsmustvindicateit.’

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(p.977).Buttowhatends?Biologicaltaxonomyisnotstampcollecting.Itservesinductivesuccess.

Thepointofdemarcatingonthebasisoflineagesisnottoidentifybranchesonatreeforitsown

sakeandstopthere,butrathertoidentifygroupsoforganismsthatareevolutionarilysignificant:

onesthataresubject,ascollectivesovertime,tobiologicalprocessesdescribedintermsof

parametersincludingselection,adaptation,andgeneticdrift.Investigatingandilluminatingallof

thisinvolvesinductivereasoningintheserviceofretrodictionsandevolutionaryexplanations

regardingthosekinds.Thesecategoriesoforganismsthusfacilitatebiologicallyimportant,

inductiveinferences.

PerhapswhatEreshefskyandReydonhaveinmindintheircritiqueisaparticularformof

induction.‘Induction’,afterall,isatermofart.Atoneextreme,onemightuseittorefervery

specificallyandexclusivelytoenumerativeinduction;atanotherextreme,itmayrefertoanynon-

deductiveorampliativeinference.Whatisappropriateinthiscontext,however,isneitherextreme,

butratherafocusoninductivereasoningthatisdirectlyrelevanttothepresumedvalueof

theorizingabouttherelevantkindsasguidestolearningabouttheworld.Onthisbasis,itisdifficult

toseehowthemeaningof‘induction’couldberestrictedsuchthatspecies,ashistoricallineages,do

notfacilitatescientificallymotivatedinductivesuccess.Takethemembersofaspecies,S,toshare

thepropertyofdescentfromacommonancestor,A.Thepredicate‘descendedfromA’isinductively

projectible.ItiscentraltoinductiveinvestigationsofrelationsbetweenmembersofS,betweenS

andotherspecies,andbetweenthemembersofdifferentspecies.Theserelationsarekeyto

understandingevolutionaryphenomena,andbyinvestigatingthemwegaininsightinto,andform

expectationsof,therelevantkindsandtheirmembers.Isitplausibletoexcludethisfromthescope

ofwhatcountsasinductivesuccess?ThefactthatsomeintrinsicpropertiesofmembersofSmay

changeovertime,ormaybesharedacrossspeciesatatime,hardlyunderminesinferencesthatare

integraltolearningaboutspeciescategoriesinevolutionarybiology.Toexcludetheseinferences

wouldbetooperatewithastrangelyimpoverishednotionofinduction.5

WhataboutEreshefskyandReydon’ssecondworry,thatthinkingofkindsascategories

‘thatfeatureinsuccessfulinferentialpractices’isapriori?Well,clearlyitis,inonesense;butinthis

senseanyaccountofkindsisboundtobe.AmomentagoIdescribedtheveryideathatthereare

5SeeKhalidiforthcomingon‘etiologicalkinds’,‘whosememberssharea…causalorigin,history,ortrajectory’ratherthanintrinsicproperties,andyetserveretrodictiveandexplanatorypurposesinvolvingancestralrelationsandcausalprocesses.Andarguably,thoughBoyd(1999,2010)takeskindmemberstosharepropertyclustersthatremainlargelystableviacausalmechanisms(despitepossiblevarianceovertime),healsoseemstooperatewithabroaderconceptionofinductivesuccess,commonlyadvertingto‘inductiveandexplanatorysuccess’or‘inductive/explanatorysuccess’.Causalexplanationsdepend,ofcourse,oninductiveinferencesestablishingtherelevantcausalrelationships.

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kindsastheupshotofsomethingakintoamiracleargumentoratranscendentalargument.Kinds

arepositedtohelpexplaininductivesuccess.Exhypothesi,itwouldbeincredibleifourinductive

practicesweresosuccessfulandyetnottrackinggenuinecategories;orperhapstheexistenceof

suchcategoriesisahighlyintuitiveorcrediblepreconditionforinductivesuccess.Butevenifone

weretocontendinsteadthatkindsarepositedtoexplainsomeotherfeatureof(say)scientific

practice–eitherway–thissortoftheorizingispartofthemetaphysicsofscience,wheresubject

mattersarenotinanyverystrictsenseaposteriori.Thisismerelytosaythatatheoryofkindsisa

philosophicaltheory.Andinanycase,giventhestructureofamiracleargumentoratranscendental

argument,alinkbetweenkindsandinductioncannotbeconsideredaprioriintoto.Kindhood,after

all,ispositedtohelpexplaintheempiricaldataofinductivesuccess,andasnotedabove,thesesame

datainformhowwethinkaboutkinds.

Havingexploredanddefendedthetraditionalideathatinductivesuccessisreasonably

consideredageneralmarkerofkindhood,letmereturnnowtothethoughtthatconventionalists

andrealistsoffercontrastingdiagnosesofhowexactlythissuccessisrealized.Herethemind-

dependent,mind-independentdistinctionloomslarge.Inordertoseewhy,asIwillargue,realism

aboutkindshasfallenonhardtimes,itwillbehelpfulfirsttoconsiderhowconventionalism

connectskindsandinduction.Thiswillserveasapreludetoseeinghowrecentarticulationsof

realismflirtwithorcollapseintoconventionalism.

3. Conventionalism regarding our knowledge of the world

Theprimarymoralofthefollowing,briefattentiontoconventionalismisthatevennon-

realistviewsofkindsareoftenandperhapstypicallyrealistaboutsomething,justnotaboutkinds

themselves–anobservationthatwillultimatelypaydividendsforthinkingaboutwhatadefensible

realisminthevicinityofkindscanamountto,ifanything.Forthemoment,recallthatthe

distinctionbetweenconventionalismandrealismis,atitscore,adistinctionconcerningthe

dependenceorlackthereofofkindcategoriesonaparticularsortofmentalstateoractivity:

conventionalismholdsthatthesecategoriesexistinvirtueofourthinkingthattheydo,andrealism

demurs.Thesearegeneralformulasfortwobroadfamiliesofviews,allowingformorespecific

versionswithineach.Letmeillustratethisfirstinconnectionwithconventionalism.

Ausefulwayofelaboratingthetraditionalnotionofamind-dependentkindisintermsof

twocentralconnotationsofthisidea,thedenialofwhichisacentralfeatureoftraditionalrealism.

Letmelabeltheseconnotations‘constructivism’and‘deflationism’.Itisaconsequenceofthefact

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thattherearedifferentwaysofconstructingandthusdeflatingkindsthatminddependencetakes

differentforms.Constructivismisthataspectofconventionalistviewsaccordingtowhichwhat

makesagroupakindisthefactthatwerecognizeitascomprisingagenuinecategory,thereby

constructingitskindhood.Inthisway,ourholdingsomethingtobeakindisconstitutiveofits

kindhood.Deflationisanimmediateconsequenceofconstruction.Deflationistsaboutxaretypically

antirealistsregardingthewayxhasbeen(perhapstraditionally)characterized–thatis,inarealist

way.Forexample,deflationistsabouttruthareantirealistsabouttruthconceivedasapropertyof

thingssuchaspropositionsorbeliefs.Theyholdthattraditional,realistunderstandingsoftruthare

mistakenormisleading;theyshouldbereplacedbyaviewthatrecastsrealistunderstandingsinto

something(putatively)lessmetaphysicallyheftyorweighty.

Asanillustrationofthissortofconstructionandconcomitantdeflation,considerThomas

Kuhn’s(1970/1962)historicistinterpretationofthenatureofscientificknowledge.OnKuhn’s

view,notmerelyscientificknowledgebuttheworlditself,duringanygivenperiodofrelative

stabilityinascientificcommunity,is(inpart)constitutedbysetsofsharedrelationsbetweenideas

–aboutsymbolicgeneralizations,metaphysics,values,problem-solvingexemplars,etc.These

matricesofcommitmentsareconstructedandheldcollectivelybycommunities,whichimbuethem

withacertainstatus,amountingtoaconstructionoftheworld(pp.111,121,150).Anything

resemblingatraditionalrealistunderstandingofscientificontology,involvingdescriptionsofand

referencetomind-independententities,isthusdeflatedintosetsofhistoricallycontingentrelations

ofideas.Similarly–hencetheidentificationoftheseviewsasmembersofabroaderfamilyqua

kinds–sociologistsofscientificknowledgeoftenrecastrealistontologyintosocioeconomicand

politicalstatusesandrelations,andsomefollowinginthelogicalempiricistandpragmatist

traditionsmayrecastitintermsofutility-drivenchoicesoflinguisticframeworks.6

Whatalloftheseversionsofconventionalismhaveincommonisaneo-Kantiankernel.One

wayofexemplifyingthisisintermsofamaximallygeneralsortofrealismabouttheexistenceofan

externalreality:thereisaworldoutthere,itexistsindependentlyofus,butitisepistemically

hubristictoimaginethatwecandescribeitasitis,noumenally.Successfulepistemicpracticesare

correlatedwiththismind-independentrealityinsomeway,suchthatourcategoriesworkwellfor

scientificorotherpurposes,butthatisallwecansayaboutthenoumena.Anotherversioncleaves

totheideathatourinabilitytodescribetheworldasitisinitselfisnotamatterofepistemic

humilitybutratherstemsfromthefactthattheverynotionofaworldindependentofconstructive

6Foradiverserangeofinfluentialtakesonconventionalism,seeGoodman1975,Rorty1980,andPutnam1983.

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conceptionsisincoherent,whichrulesoutanysortofrealismtraditionallyconstrued.Eitherway,

thegeneralityofbothoftheseversionsconventionalismentailsaconventionalismaboutkinds:we

cansaynothingaboutthenoumena;afortiori,wecansaynothingaboutnoumenalkinds.Crucially,

however,givenourmorespecificfocushereonkinds,wemayaddtothislandscapeof

conventionalistpossibilitiesamorediscerning,thirdoption:aconventionalismaboutkinds

specifically(perhapsinteralia),combinedwitharealismaboutcertainotheraspectsofreality.7

Whicheverversionofkindconventionalismoneadopts,onemayofcoursedescribethe

phenomenalworldmakingupourempiricalrealityinanthropomorphicwayswithrespecttokinds,

andevensuccessfullysofarasinductionisconcerned.Whatonecannotorshouldnotattemptto

assertisanythingontologicallydefinitiveaboutostensiblynoumenalkindsinvirtueofwhichour

inductivepracticesaresuccessful.Rather,itisourthinkingthatacategoryisgenuine,ideally

supportedbyasubstantialorotherwisesignificantdegreeofinductivesuccess,thatmakesitakind.

Onceagain,ananalogytodebatesaboutscientificrealismmaybehelpful,thistimein

illustratinghowadeflationaryattitudetowardonethingmayresultinarecastingthatembodiesa

differentsortofrealismaltogether.Inresponsetoskepticalworriesaboutunobservableentities

describedbyscientifictheories,JohnWorrall(2007)arguesthatscientificrealistsshouldsimply

endorsetheRamseysentencestructureofourbesttheoriesinstead.ToformtheRamseysentence

ofatheory,wesubstituteitstermsforputativeunobservableswithexistentiallyquantified

predicatevariables,andvoilà,theskepticism-fuelingcontenthasbeendisplaced,allowingrealists

tofocusontherelationalstructureofthetheoryinstead.Butnote:intheprocess,therealismat

issuehasshiftedprofoundly.Whatwasarealismaboutunobservableentitieshasbeenrecastinto

somethingratherdifferent.Thevariablesneednotreferinanydeterminateway.Onemightsaythat

theworld,aboutwhichoneisarealist,isjustsuchthattherelationsexpressedintheRamsey

sentenceobtain;thisjudgmentwouldreflectthe(inductive)successassociatedwithourbest

theories.Similarly,aconventionalistaboutkindssaysthatwhatrealistsregardasmind-

independentkindsshouldberecast.Perhapstheworldissimplysuchthatourclaimsaboutcertain

categoriesprovesuccessful,orperhapsrealismaboutsomeotheraspectsoftheworldunderwrite

thissuccess.Eitherway,itisourrecognitionofthecategoriesthatmakesthemkinds.

Letmeextracttwothoughtsfromthisbriefoverviewofconventionalism.First,asinthe

caseofrealism,conventionalismiscompatiblewithtakinginductivesuccesstobeageneralmarker

ofkindhood.Itisjustthatonthelatterview,thisindicatorrevealsnothingsubstantial(ornothing

7Afterconcludingmyargumentagainstkindrealism,insection5,section6willsuggestthecombinedoptionastheonlypossibilityremainingforthoseinclinedtowardarealistdiscourseofkinds.

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atall)aboutkindhooditself–theexistenceofacategory–thatwouldqualifyasmindindependent,

owingtoitsconstructivismandassociateddeflationism.Second,leavingasidethequestionof

whetherWorrall’spositionisreallyaformofscientificrealism,theanalogyintimatedbythis

questionisnonethelesssuggestive.Iwillreturntoitinsection6,whereIconsiderwhetherthereis

anypositionthatisbothdefensibleandsufficientlyrealistaboutkindsspecificallytomeritthe

label.JustasWorrallattemptstoweakentraditionalformulationsofscientificrealisminreplyto

skepticalconcerns,thereisstrongmotivationamongkindrealiststoweakentraditionalformsof

kindrealism,anditwillbehelpfulinwhatfollowstoretainthethoughtthatrealismregardingthe

existenceofamind-independentworld,orcertainaspectsoftheworldsuchasparticulars,

properties,causalrelations,laws,etc.,doesnotbyitselfamounttoarealismaboutkinds.

4. Updating traditional realism: ambiguity and collapse

Ihaveelaboratedthecentraltenetofconventionalism,theminddependenceofkinds,in

termsoftwomainconnotations,constructivismanddeflationism.Realismandthemind

independenceofkindsmayalsobeelaboratedintermsoftwomainconnotations:thedenialofboth

constructivismanddeflationism.Itisunsurprising,perhaps,thatonreflection,mindindependence

ismostobviouslycharacterizedinthisnegativeway,foralthoughtheassertionthatakindexists

independentlyofitsbeingthoughttoexistisasubstantialmetaphysicalclaim,itisnoteasyto

expandonitwithamoredetailed,positivecharacterizationthatalsosucceedsinexplainingthe

intimateconnectionbetweenkindsandinductivesuccess.Iwillfocusonthiscontentionshortly(in

section5),buttosetthestage,letusmoveforwardwithourworkingcharacterization,accordingto

whichrealismaboutkindsisconceivedasdiametricallyopposedtoconventionalismintermsofthe

principalconnotationsnotedabove.

HereIaimtomotivatetheideathatsayingsomethingmoreaboutthemind-independent

natureofkindsisforceduponrealistsassoonastheyattempttosquarethemetaphysicaland

epistemologicaldimensionsoftheirrealism–thatis,mindindependenceandinductivesuccess.In

arguingforthisIwillciteanumberofrecentlydevelopedviews,andmuststronglyemphasizeat

theoutsetthatitisnotentirelyclearwhetheranyofthemis,infact,intendedtobecompatiblewith

kindrealismasIhavedescribedit,traditionally;someareclearlynotsointended.Whatisclearis

thatalloftheirauthorstakethemselvestobepresentingviewsthatareinsomewayrealist,evenif

itisnotalwaystransparentwhethertherealismatissueattachestokindcategoriesspecifically,to

somethingelse,ortoboth.Furthermore,forallIsayinwhatfollows,theymaybecoherentviews.

Chakravartty Natural Kind Realism

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Myaimissimplytosuggestthatthesein-some-way-realistorpossibly-kind-realist-compatible

viewsareeither(1)ambiguousquarealismaboutkindsthemselves,or(2)conventionalist,the

surfacedescriptionsofthesepositionsnotwithstanding.

Amonganumberofnowlargelyabandonedideasassociatedwiththerealisttraditionof

theorizingaboutkinds,oneinparticularhassufferedgreatlyinrecentdecades:theideathatkinds

formaunique,hierarchicalsystemofcategorieswithstrictsubsumption,accordingtowhich‘ifany

twokindsoverlap,thenonemustbesubsumedundertheotherasasubkind’(Tobin2010,p.179).

Thisportraitofamonistickindstructureoftheworldhasnowbeenwidelysurrendered,notleast

becauseofthedifficultyofmakingsenseofitinthecontextofthesciences–presumablyan

exemplarysetofinvestigationsforrevealingkinds–wherewhatwecommonlyfindarenotunique

hierarchicalsystems,butratherdifferent,co-existingsystemswhosecategoriesoftencrosscutone

another,violatingtheconditionofstrictsubsumptionandsuggestingapluralisticportraitofkind

structureinstead.Awidelydiscussedillustrationofthisisthecaseofbiologicalspecies.Acrossthe

breadthofthefield,biologistsdonotclassifyorganismsintospeciesinonlyoneway.They

taxonomizeonthebasisoflineages(aswehaveseen),butalsoonthebasisofreproductivefertility,

ecologicalroles,andinotherways.Theconsensusdiagnosisofthispluralisminpracticeisthat

differenttaxonomicsystemsneednotbeincompetitionwithoneanother,butsimplybettersuited

topursuingdifferentaims.Differentformsofinductivesuccessareoftenbetterachievedusing

differentclassificatorysystems,evenwithinadomain.8

Giventheimplausibilityofthetraditionalrealistpictureofasinglesubsumptive

classificatorysystem,kindrealismrequiresanupdateinthisrespect.Butwhatsort?Ifthe(mind-

independent)existenceofkindsistobepartofanexplanationofinductivesuccess,andthesuccess

ofcertainscientificpracticesisatleastpartofthisexplanandum,anyupdatetokindrealismmust

takethesepracticesseriously.This,however,ispreciselywhererecentdiscussionshave

underminedprospectsforrealismaboutkindsspecifically,fortakingscientific-inductivesuccess

seriouslyhasresultedinpositionsthatare,Isubmit,eitherambiguousregardingtheirendorsement

ofmind-independentkindcategories,orseeminglyrealistaboutthingsotherthankinds.Letus

focusfirstonpossibleambiguities:descriptionsofkindsthatdonotmerelylinkthemtoscientific

practice,butalsoflirtwiththesuggestionthatthispracticeisinsomewayresponsiblefor

8Thereisabundantsupportforthisconsensus.SeeKitcher1984,Ereshefsky1992,andDupré1993forearlierworkonspeciespluralisminbiology.Khalidi1998andTobin2010arguethatuniquehierarchicaltaxonomywithsubsumptionisunderminedbycrosscuttinginthesciencesmoregenerally.Ruphy2010exploresthevarietyofwaysstarsareclassifiedwithdifferentpredictiveandexplanatorygoalsinmind.Longino2013detailsfourdifferentapproachestostudyinghumanaggressionandsexuality,eachofwhich‘parses’causalfactorsindifferentways.

Chakravartty Natural Kind Realism

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constructingtherelevantkinds.AsIwillnowillustrate,thisamountstoanambiguitybetween,on

theonehand,simplynotingthatourinterests–aims,goals,purposesofinquiry,questionsposed,

answerssought–maybebetterservedbytheorizingintermsofonetaxonomyratherthananother

(whichiscompatiblewithmindindependence),andontheotherhand,takingourintereststobe

constitutiveofkindhood(whichisnot).

Letmelabelthetwosidesofthisambiguity.Onthefirsthand,humanthinkingaboutkinds

entersonlyintheacknowledgmentofaprocessoffiltration:ourinterestsalignwithpracticesthat

filterout,amongthevariouskindsandsystemsofkindsthatexistindependentlyofourthinking

theydo,theonesthatwehope(andideally)aretheonesbestsuitedtosuccessfulinductive

inferencesinrelationtothoseinterests.Letuscallthisa‘filteringapproach’totakingscientific-

inductivesuccessseriously;ourinterestspromptustotriangulateon,andsofacilitatethefiltering

of,mind-independentkinds.Onthesecondhand,humanthinkingaboutkindsentersinthemanner

ofalathe:ourinterestsalignwithpracticesthatultimatelyshapeandtherebyconstructakindor

systemofkindsthatexistsbecauseourthinkingaboutthesecategorieshypostatizesorreifiesthem.

Letuscallthisa‘constitutingapproach’totakingscientific-inductivesuccessseriously;our

interestspromptustofashionkindsthatwehope(andideally)arewellsuitedtosuccessful

inductiveinferencesmadeinrelationtothem.Somerecentworkthatmaybeviewedasattempting

toupdatethekindrealisttraditiongivestheimpression,Ithink,ofwobblingontheborderbetween

filteringandconstituting.

Consider,forexample,Magnus’(2012)account.Hebeginsbynotingthat‘different

enquiriesrequirecuttingalongdifferentjoints’(p.1).Thissuggestsfiltering–thePlatonic

metaphoriscustomarilyinvokedtoconveytheideathatkindsaremindindependent–andinthis

spirithelaterconfirmsthat‘whether[kinds]aretheredoesnotdependonus’(p.119).These

remarks,however,bookendsomewhatenigmaticadditions:‘Itisaconstraintonouraccountof

naturalkinds…thattheyformcomponentsofsuccessfulscientifictaxonomy’(p.20).Now,fromthe

pointofviewoffiltering,thismightseemtoputthecartbeforethehorse.Thesciencesareableto

triangulateoncertaincategoriesbecausetheyexist;theydonotexistbecausetheyfigurein

scientifictaxonomy.Magnus’intentionhereseemsdifferentinitially:nottosaythatkindhood

dependsonscientifictheorizingandpractice,butthat‘anaccount’ofkindssodepends–areading

thatechoesmycontentionearlierthattheorizingaboutkindsisnotentirelyapriori,sinceitis

informedbytheempiricaldataofinductivepractice.Butthenheappearstoshiftintothemodeof

constituting:‘Insofarasscienceissomethingwedo,thenaturalkinds…willbethingsthatdepend

onus’(p.20),aswellasontheworld‘insomeway’(p.26).Otherclaimsmightbereadasconflating

Chakravartty Natural Kind Realism

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filteringandconstituting:‘thenaturalkindsweidentifymayberealquanaturalkindsand

dependentonusquaouridentifying’(p.104).Butiftheexistenceofakinddependsonour

identifyingitassuch,thenitdoesnotexistmindindependently.

Again,letmeemphasizethatthejuxtapositionofthesequotationsisnotintendedcritically,

butmerelytoillustratethestraininvolvedinattemptingtoupdatekindrealisminawaythatdoes

justicetotheroleofinductivesuccessintheorizingaboutkinds.Ambiguityregardingthecore

stickingpointbetweentraditionalrealismandconventionalism,namely,mindindependence,is

hardlyasurprisingconsequence.MatthewSlater(2013,pp.171-176)seemsunequivocalinhis

rejectionoftraditionalrealism:itisamistake,hethinks,toregardkindsascomprisingan

ontologicalcategory;kindhoodissimplyastatusconferredonacategorywithinadomainof

inquiryonthebasisofitservingwhateverepistemicinterestsarepresentthere.Thisrelativizes

kindhoodtointerestsandinvestigations,whichsuggestsconstituting,butevenso,adegreeof

ambiguityconcerningrealismcreepsin:‘thecontributionsofouraimsandinterestsplaya

parameter-settingrolewithoutsaturatingtheresultantkindswithsubjectivity’(pp.171-172).

Thereinliestherub.Saturationadmitsofdegrees;mind-independentexistencedoesnot.Attempts

tomergekindrealismwithtaxonomicpluralismbymeldingmindindependenceanddependencein

descriptionsofkindshasproducedacertainamountofambiguitywithrespecttorealism.

Whilehintsofrealismappearinaccountsofkindsthatedgetowardconventionalism,some

donotedgesomuchasstraightforwardlyrelinquishtheirrealistcredentialsregardingkinds

specifically.AclearexampleofthelatterisBoyd’s(2010,p.220)accountof‘accommodation’,on

whichkindtalkisunderstoodintermsofameshingoftaxonomicpracticesandcausality:‘the

theoryofnaturalkindsjustis(nothingbut)thetheoryofhowaccommodationis(sometimes)

achievedbetweenourlinguistic,classificatory,andinferentialpracticesandthecausalstructureof

theworld.Anaturalkindisnothing(much)overandaboveanaturalkindtermtogetherwithits

useinthesatisfactionofaccommodationdemands.’Boydelaboratesthisbysayingthat‘natural

kindsaresocialconstructions’;‘Inacertainsensetheyaremind,interest,andprojectdependent.’

Asnotedearlier,claimssuchastheseareslogansforconventionalism.Theysatisfythegeneral

formulaofneo-Kantianconstructivism,accordingtowhichkindsarejointfeaturesoftheworldand

ourminds.Granted,manyimplementationsofthisformulataketheworldinitselftobemind

independent,butthisdoesnotalterthefactthatanyviewonwhichtheexistenceofsomethingis

partiallyconstitutedbyourthinkingthatitexistsisaformofconstructivism–whichis,recall,a

principalconnotationofconventionalism.

Chakravartty Natural Kind Realism

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Boyd(2010,p.221)iskeentoavoidthisdiagnosisandrejectsthesuspicionthat

accommodationiscomparabletoaneo-KantianconstructivismàlaKuhn,onthebasisthat‘human

conceptualandinferentialpracticesmustbeaccommodatedtothecausalstructuresofthe

phenomenaunderstudy,notviceversa’;‘humansocialpracticesmakenonon-causalcontribution

tocausalpropertiesandrelationsintheworld’.Butthissuggestsonlythathisnotionof

accommodationisnotwelldescribedbyaparticularinterpretationofKuhn,notthatitisrealist

aboutkinds.Realismaboutvariousthingsinrelationtocausation–causalproperties,causal

relations,causalstructures–issimplynotthesamethingas,nordoesitrequire,realismregarding

kindcategories.Causationisoftenanalyzed,forinstance,asarelationbetweeneventsorfacts,oras

aprocess,butnoneofthesebroadapproachestothemetaphysicsofcausationentailsrealismwith

respecttokinds.

Similarly,Reydon(2016,p.60),whiletakingaclearstandonthequestionoffilteringversus

constituting–‘kindsaremadebyus,ratherthansimplyfoundinnature’–neverthelessassertsthat

thisshouldbeacceptabletokindrealists.Onhis‘co-creationmodel’,‘bothnatureandwe–asthose

whodotheclassifying–fundamentallycontributetothecreationofkinds’(p.70);kindsare‘co-

determinedbyaspectsofthestateofaffairsinnatureaswellasbybackgroundassumptionsand

decisionsbyinvestigators’(p.59).Butagain,arealismaboutaspectsofstatesofaffairsdoesnot

entailarealismaboutkindsunlesskindsthemselvesarecountedamongtherelevant(mind-

independent)aspects.Onceonegoestherouteofkindconstructivism,evenifsomeofthe

componentmaterialsoutofwhichkindsareconstructedaremindindependent,realismregarding

theexistenceofthecategoriesthemselveshasbeendeflated.

Itisfair,Ithink,towondernowwhetherthisismerelyaterminologicaldispute:doesit

concernnothingmorethanadisagreementabouthowtodefine‘realismaboutkinds’?Idonot

thinkso.Havingnotedthatunderstanding‘realism’intermsofmind-independentexistencereflects

adeeplyentrenched,historicaltraditionofuse,myconcernhereisnottopreservetradition;itisto

investigatewhetherkindrealismthusunderstoodisviable.TheviewsIhavejustdiscussedareby

nomeansexhaustiveofrecentthinkingthatmayappearambiguousinthislight,orthatamountto

conventionalism.Theyare,however,representativeofatrendinwhichthelabel‘realism’hasbeen

appliedlooselywherekindsareconcerned–somuchsothatoncloserexamination,thoughthey

maybeviewed(inatleastsomecases)asattemptstoupdatetherealisttraditionoftheorizing

aboutkindssoastogivedueweighttoinductivesuccess,theycannotbeseen(clearlyoratall)as

remainingwithinthattradition,asunderstoodintermsofitsmostcentralcommitments,tothe

mind-independentexistenceofkindsandarejectionofconstructivismanddeflationism.Letus

Chakravartty Natural Kind Realism

16

moveonnowtoconsiderwhatprospectsmayyetsurviveforkindrealismonastricteradherence

tothesecommitments.

5. Hyperrealism: bridled versus unbridled promiscuity

Iftheideaofamind-independentexistenceforkindsistobeadoptedstrictlyratherthan

finessed,themetaphoroffilteringinvokedintheprevioussectionmustbemarriedtothe

taxonomicpluralismwefindinherentininductivesuccess.Asperrealism,filteringisaprocess

wherebyinductivepracticestriangulateonmind-independentcategories:kindsthatexist

independentlyofourinterestsandscientificdisciplinesarediscernedandselected,oftenvia

painstakinginvestigationandtrialanderrorovertime,fromamongother(sometimescross-

cutting)categoriesofthingsthatmaylikewiseexistmindindependently.Thetraditional,kind-

realistconvictionthatkindsare“outthere”isintendedtodojusticetothisprocessoffiltering

throughempiricalinquiry.Ratherthanmoveinthedirectionofconventionalism,thestalwart

realistholdsthattherearemanycrosscuttingcategoriesofentitiesthatexistindependentlyof

beingthoughttoexist.Sincethisamountstoanextendedapplicationofthecorecommitmentof

mindindependencetoamuchbroaderclassofcategoriesthanwasonceendorsedbyrealistsonthe

nowoutmodedconceptionofaunique,subsumptivetaxonomyofkinds,letuscallthisposition

‘hyperrealism’.

Thoughhyperrealismisclearlyanextensionofanearlierincarnationofrealism,thevery

ideaofitraisesaquestionaboutitsproperextent.Thismightbenarrowlyconstruedasa

metaphysicalquestionwithacorrespondinglynarrowanswer:theproperextentofhyperrealismis

limitedtothosekindsthatare,infact,mindindependent.However,itistheepistemological

dimensionofrealismthatisatissuehere.Takingscientific-inductivesuccesstobeindicativeof

mind-independentkindsinpracticedoesnotbyitselfamounttoclearguidanceregardingwhat

formsofinductivesuccessshouldbeconsideredthusindicativeinprinciple.Actualscientific

practicecomprisesanegligibleproportionofpossiblescientificpractice,whichmay(forallwe

know)involvedifferentformsofinductiveinferenceandstandardsofsuccess.Furthermore,one

maywonderwhetherinductivesuccessisproperlyconsideredmorelikelyindicativeofkindhood

whenitoccursinthesciencesasopposedtoothercontexts,manyofwhichinvolveinquirythatis

alsoinductivelysuccessfulandsometimeshighlysystematic.Herewefinddramaticallyconflicting

intuitionsabouttheproperscopeofhyperrealism,andthepositionfacesaseriouschallenge.Iwill

Chakravartty Natural Kind Realism

17

nowsuggestthatanyattempttodeterminetheproperextentoftheviewfacesadilemma,with

conventionalismloomingononesideandincoherenceontheother.

LetmeframethisargumentwithanexampleintroducedintorecentdiscussionsbyJohn

Dupré(1993,pp.29-30).Dupré’s‘promiscuousrealism’wasinpartareactiontotheideathatonly

categoriesdelimitedbythesciencesaregenuinekinds.Hisbasiccontentionwasthatwhilethe

sciencesmaywelltrackkinds,thereisultimatelynodefensiblereasontothinkthatscientific

taxonomyisuniqueinthisrespect.Ifthefolkcategory‘fish’includeswhales,andthiscategoryso

configuredsupportsinductiveprojectionsthatarerelevanttothefolk(say,fisherfolk),itisthen

arguablyagenuinekind,evenifscientistsclassifywhales,whicharemammals,inaseparate

categoryfromfish,whicharenot.Folkandscientificcategoriesareoftenexamplesofcross-cutting

kinds.Onemightworry,ofcourse,thatinourmodernscientificerathisexampledoesnotpumpthe

intuitionsitwouldhaveearlier.Perhapsthefolkconcept‘fish’nowexcludeswhalesformost

people;thisaspectofscientifictaxonomymaynowhavebeenabsorbedintobroaderlinguistic

practice.Inthatcase,wemightpumptherelevantintuitionssimplybyimaginingatimebeforethis

wasthecase,orbyhelpingourselvestoanynumberofcontemporaryexamples.9

Herewemustfinallyconfronttheissueof“naturalness”.Earlier,toavoidconfusion,I

promisedtousetheterm‘kind’sansqualificationuntilitwasnecessarytodootherwise,because

‘naturalkind’isusedbyrealistsandconventionalistsalikebutindifferentways.Now,however,let

usfocusonpossibleinvocationsofnaturalnessasanotiontowhichhyperrealistsmightappealin

ordertodelimittheproperextentoftheirposition.Recallthat‘natural’,inthiscontextofrealist

usage,routinelyfunctionsasasynonymfor‘objective’or‘mindindependent’.Clearly,though,ifthis

synonymyexhauststhemeaningoftheterm,naturalnesscannotfunctionasanindependent

criterionforrecognizingwhatismindindependent,becauseonthisusage,tosaythatsomethingis

naturalistosaynothingmorethanthatitismindindependent.Inorderthatnaturalnessfunction

asahelpfulindicatorofmindindependence,itmustbesomethingthatwecanapprehendinitsown

right.Thisisthecruxofthedifficultyforhyperrealism.Attemptstospecifytheproperextentofthe

viewallendup,onewayoranother,appealingtotheideathatsomecategoriesarenaturaland

othersarenot(someevenclaimthatcategoriescanbemoreorlessnatural).Butlackingan

9Ludwig(2017)considerscasesfromethnobiology,thestudyofhoworganismsareunderstoodindifferentcultures.E.g.,itiscommoninindigenoustaxonomiestoclassifybatstogetherwithbirds,contrabiologicalsystematics.Thisishardlysurprisinggivenamultitudeofinductiveinferencesunderwrittenbytheircommonalities:‘bothtypicallyhavewings,alightbonestructure,akeeledsternum,asimilarsizerange,streamlinedbodies,highmetabolism,migratorybehaviour,similarnaturalenemies,afruit-andinsect-baseddiet,andtheybothtypicallyfly,disperseseedsintheenvironment,reducelocalinsectbiomass,andsoon’(p.193).

Chakravartty Natural Kind Realism

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understandingofnaturalnessthataffordssuchjudgments,theseappealshavenoprobativeforce,

andasIwillnowcontend,thereisnosuchunderstanding.

Presumably,inordertodiscernthepresenceorabsenceofnaturalnesshere,weshould

havesomewayofevaluatingand/ortrackingcategoriesfroma“nature’s-eye”pointofview.Thisis

whereconflictingintuitionssurfaceregardingwhatsuchavantagepointwouldreveal,butthe

challengeforhyperrealismisevenmoreseverethanthismightsuggest.Thefataldifficultyisthat

welackanunderstandingofnaturalnessthatiscapableofdoingtheworkforwhichitisrequired:

namely,tospecifyanindicatorofmindindependencethatismorediscriminatingthan(mere)

inductivesuccess.Anycandidateforgenuinekindhoodwillbeassociatedwithsomesuchsuccess–

whetherwithinoroutwiththesciences,inactualityorpossibility,etc.–soifnaturalnessistobe

calledupontoestablishtheproperextentofhyperrealism,itmustbeafeatureofonlysomesuch

categories;thatis,afeatureofsomebutnotallcategoriesthatfacilitateinductivesuccess(orthat

woulddosounderappropriateinvestigationalcircumstances).Whatmightthisbe?

Considerfirstthepossibilitythatevenwithoutgivingaqualitativedescriptionof

naturalness,wemightsimplytrackthetrulynaturalkindsbytakingthesciencestobeexclusive

arbitersofgenuinekindhood.Ifsuchdeferenceweredefensible,thismightserveasabasisfor

puttingabridleonpromiscuity–injustthewayDuprétriedtoresist.However,giventhatinductive

successissufficienttonominateacandidatekind,andlackingadescriptionofnaturalnesswith

whichtoexplainwhyscientificcategoriesarenaturalandextra-scientificonesarenot,itisdifficult

toseehowablanketdeferencetosciencecouldbewarranted.Perhapsthehyperrealistcouldtake

inspirationfromEreshefskyandReydon’s(2015,p.984)claimthatitwouldbewrongtothinkthat

theterms‘fish’and‘Mammalia’(forinstance)bothrefertonaturalkinds,becausefolkbiologyand

scientificbiologyarecompetingtaxonomicprograms,andthelatterispreferablebecause‘The

categoryfishisnotpartofanycurrentprogressiveclassificatoryprogram.’Butthiswillnothelp,

foratleasttworeasons.First,sincethefolkcategoryandthescientificcategorysupportdifferent

sortsofinductiveinferences,andthus(notsurprisingly)servedifferentaims,itisamistaketo

thinkofthemasbeingincompetition.Second,whilethequestionofwhetheraclassificatory

programisprogressiveordegenerating,touseImreLakatos’celebratedterminology,maybe

aproposofscientificresearchprograms(asLakatosintended),itcutsnoicehere.Thatdistinction

wasneverintendedtosetlimitsonwhatisnatural.10

10Forthemakingsofanother,possiblechallengetotheideaofconstraininghyperrealismbydeferringtoscience,seeConix2019,pp.31-33,whoarguesthatgiventhewayclassifications(e.g.,ofspecies)mayvaryaccordingtolocalaimsandnorms,andinterpretationsandoperationalizationsofsharednorms,scientifictaxonomyitselfplacesnoconstraintsontheextentofhyperrealism.

Chakravartty Natural Kind Realism

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Letusbroadenourthinkingaboutwhichcategoriesexemplifynaturalness,then,beyonda

blanketdeferencetothesciences.Intheabsenceofacompellingdescriptionofwhatnaturalnessis,

however,thetaskofdelimitingthesecategoriesremainselusive.MuhammadAliKhalidi(2013,p.

62)suggeststhatwhileplacingwhalesinthecategoryoffishmayservecertaininductivepurposes,

‘notallpurposesarecreatedequal’.Doesthismeananythingfromanature’seyepointofview?Itis

difficulttoseewhyorhowthepurposesofevolutionarysystematistsaresuperiorquanaturalness

tothepurposesoffisherfolkoreco-tourists.Khalidiassertsthatsomepurposesareepistemically

superiorwithrespecttodesideratasuchaspredictionandexplanation,andthat‘ourbestepistemic

practicesaimtouncoverthedivisionsthatexistinnature’(p.63).Butasastrategyfordelimiting

whatisnatural,thisfaresnobetterthandeferringtoscience,becauseitishighlysuspecttoimagine

thatthereisanyabsolutesenseinwhichjudgmentsofcomparativeepistemicgoodness

(‘superiority’)canbemade.Theinherentaimsofinvestigativecontextsdeterminewhatinductive

inferencesandknowledgearebestthere–andthisvariesbetweencontexts,whetherinthe

sciencesorotherwise.Thereisnosuchthingasanabsoluteorcontext-freemeasureofepistemic

superiority,andtoassumeotherwisemerelythreatenstobegthequestion.

Otherattemptstoidentifycategoriesimbuedwithnaturalnessindirectly–thatis,while

lackinganaccountofnaturalnessitself–arelikewiseunconvincing.Onestrategyistoappealto

intuitivenotionsofsignificanceorimportance:itisobviousonintuitivegrounds,somehave

claimed,thatsomecategoriesrepresentsignificantorimportantcollectionsofthingsandothersdo

not.Ifthiswereso,onemightthendefinetheproperextentofhyperrealismintermsofcategories

that,invirtueofcomprisingsignificantorimportantcollections,arejudgednatural.Thisseems

desperate,though,forsignificanceandimportanceareparadigmexamplesofanthropocentric

qualities.Andtoreturntoanowpredictabletheme,judgmentsaboutwhatisorisnotsignificantor

importantarecontext-relative,notabsolute.Imagineaddingallofthenowunforeseencontextsof

futureinvestigation(letalonethoseofallpossibleinterest)tocontextsofcurrentinterest,whether

inthesciencesorbeyond;thenotionthatwhatappearsimportantatanygiventimeorplaceisan

indicatorofthelimitsofwhatisnaturalnowseemsallthemorecontrived.Similarskepticism

awaitspossiblevariationsonthethemeofimportance.AviewoftencreditedtoMill(1846,PartI,

chapter7,section4),forinstance,isthatwhatmakesakindnaturalisthesharingoflargenumbers

ofsignificantproperties.Whythisshoulddelimitwhatisnatural,however,isopaque.11

11Theviewisalsoimplausible.Themembersofmanycanonicalscientifickinds(e.g.,subatomicparticles,chemicalelements)shareonlyafewdistinctiveproperties.Howmanyissufficientfornaturalness?Icannotdiscussfurthervariationshere,butwillflagonemore:someconstrue‘importance’as‘informativeness’,whichhasbeenelaboratedininformationtheory.Ross&Ladyman(2007,pp.196-238)buildonDennett’s

Chakravartty Natural Kind Realism

20

Theupshotofthisdiscussionisadilemmaforhyperrealism.Themotivationfortheposition

iscompelling:onceweappreciatethedepthofconnectionbetweenpositingkindsandinductive

success,scientificandotherclassificatorypracticesinevitablydrivekindrealisminamore

pluralisticdirectionthanwasoncethenorm.Thisrealization,however,immediatelyraisesa

seriousquestionregardingwhetherthereareanyconstraintsatall,beyondinductivesuccess,on

whatisproperlyrecognizedasakindasperrealism(cf.Lemeire2018).Therearetwooptionshere

forhyperrealism.Aswehaveseen,onemayattempttoreignitinbyadducingthecriterionof

naturalness.However,beyondtheunhelpfulplatitudethatwhatisnatural(inthissphere)ismind

independent,articulatingwhatnaturalnessis,precisely,hasprovenabridgetoofar.Commonly

suggestedproxiesfornaturalness,suchasscientificauthority,epistemicsuperiority,significance,

andimportance,failtodemarcatewhatisnatural–kindsdelimitedfromanature’seyepointof

view–asopposedtocategoriesthatmerelyreflecthumanpreferences.Totakeanysuchproxyas

determiningtheproperscopeofhyperrealismamountstoamerestipulationofwhichkindsare

“real”.Butthisissimplytoadoptaconventionforrecognizingcertaincategoriesasgenuinekinds.

Thus,onthishornofthedilemma,hyperrealismcollapsesintoconventionalism.

Alternatively,hyperrealistsmaybitethebulletandinterprettheirviewasakindof

maximalismaboutkinds.Onthisinterpretation,movedbyourfailuretocharacterizenaturalnessin

anyhelpfulwayasanindicatorofmindindependence,onesimplyextendsrealismtoanyandall

categoriesthatfacilitatesomemannerofinductivesuccess,orthatwouldunderappropriate

investigativecircumstances.Butthisisincoherentquarealism,forweknowthattheexistenceofat

leastsomeinductivelysuccessfulkindsisnot,infact,mindindependent.Recalltheexampleof

money,theexistenceofwhichassuchdependsonbeliefstotheeffectthatitismoney.Kindrealism

cannothangitshatoninductivesuccessalone,forthiswouldresultinanextensionofrealism,

whichbydefinitionconcernsonlykindswhoseexistenceismindindependent,tokindsthatare

knowntoexistminddependently,amountingtoareductio.

Thisisthefateofrealismaboutkindcategories–dissolutionintoconventionalismonthe

onehand,orincoherenceontheother.Stipulatingproxiesfornaturalnesstoserveasindicatorsof

mindindependencecannotdotheworkthatrealismrequires,fortheyareinherently

anthropocentricandassessedinwaysthatvarycontextually.Refusingtostipulateleavesus

withoutanyrestrictionsonhyperrealismatallbeyondinductivesuccess,whichinaworld

(1991)ideaof‘realpatterns’tosuggestthatdatapatternssatisfyingaconditionofmaximumcompressibility,orcompactness,representkinds.Butagain,varyingdegreesofcompactnessareoptimalfordifferentinductivepurposes,andonemaywonderwhycompactnessshoulddelimitwhatisnatural.

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putativelyinhabitedbymind-dependentandmind-independentkindsalike,leavesrealists

conflatingtotwo.Skeweredonthisdilemma,naturalkindrealismhasrunitscourse.

6. Remnants of realism: deflationism and mind independence

Inconclusion,letmebrieflycommentontheimplicationsoftheuntenabilityofrealism

aboutkindsspecificallyforrealismmoregenerally.Thisseemsimportantnotleastbecause,inwhat

maynowseemacountervailingspirit,thereisclearlypotentialhereforsignificantredemptionon

thepartofformerkindrealistswhoarenowbereft.Fromamoregeneralrealistperspective,itis

hardlysurprisingthatmanyhavestrainedtoretainsomeformofrealisminrelationtokind

categories,evenwhiletheorizingaboutthemhasrenderedthisprospectincreasinglyfraught.

Conventionalismisitselfcontroversial–theneo-Kantiankernelcanbehardtodigest–andmany

findthisastrongmotivationforclingingtorealismanditspromiseofknowledgeofamind-

independentworld.Thedemiseofkindrealism,however,doesnotentailthatpropositions

regardingkindscannotbetrueorfalseinjustthewaythatrealistscrave:objectively,suchthat

truthvaluesdonotdependonanycontributionsourthinkingmaymaketoconstitutingtheworld;

inotherwords,mindindependently.Thisfollowsfromthesimplefactthatwhilekindsdonot

themselvesexistmindindependently,thetruthmakersofclaimsregardingthemmaywellexistin

justthisway.Itissimplythecasethatkindcategoriesarenotamongthosetruthmakers.Inhopesof

knowledgeofamind-independentworld,manywhohavestruggledtoholdontorealismin

connectionwithkindshavesimplymisappliedthelabel‘realism’.

InadvertingtotruthmakershereIdonotmeantoinvokeanyheavy-dutysemantic

machinery.Considersomeanalogies.Mereologicalnihilismistheviewthatfromthepointofview

ofontology,onlysimples(entitieslackingproperparts)exist.Assumingthattablesare(ultimately)

madeupofsomesuchcomponents,thereare,strictlyspeaking,notables–thoughthereare

certainlycollectionsoftherelevantcomponents‘arrangedtable-wise’.Thisdoesnot,ofcourse,

precludemind-independenttruthsorfalsehoodsregardingtheheightsoftables,theirmasses,and

soon,andthisissoeventhough,onthisview,tablesthemselvesdonotexist.Similarly,oneneed

notbearealistaboutnumberstoholdthat‘2+2=4’isobjectivelytrue.Analogously,onemayhold

thatwhiletherearenomind-independentkindcategories,thereareneverthelessclaimsabout

kindsthataretrueorfalseinamind-independentway.Thiswouldbetosaythattherearemind-

independentaspectsoftheworldinvirtueofwhichclaimsaboutkinds,whichdonotthemselves

existmindindependently,areobjectivelytrueorfalse.Particularsandrelationsofsimilarity;co-

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occurrences,clusters,correlations,anddistributionsofpropertiesinspacetime;causalrelations,

mechanisms,andstructures…Allofthesethingsmayexistmindindependently,underwritingthe

objectivetruthorfalsityofpropositionsregardingkinds.

Aswehaveseen,someattemptstoclingtorealismaboutkindsendupidentifyingwhatis

(mind-independently)realwithotherthingsinstead,andthisconflationofkindrealismwithother

realismsunderlyingkinddiscourseisnowsowidespreadthatitoftengoesunnoticed.12Obscuring

this,however,onlyservestoobscuretheupshotofmillenniaoftheorizingaboutkinds.Inorder

thattheythemselvesbeentitieswhoseexistenceisamenabletorealism,kindsmustexistmind

independentlyoverandabovetheexistenceofcausalrelations,clustersofproperties,etc.,about

whichonemaybearealistonindependentgrounds.Kindsdonotexistthisway,asanontological

categoryintheirownright,butwemayhaveobjectiveknowledgeofthemnonetheless,andthis

leavesmuchtoarticulateregardingconceptionsofproperties,causation,etc.thatarecentralto

practicesofclassification.Hencetheredemptionforerstwhilekindrealists:mind-independent

knowledgeoftheworldinrelationtokindsmaybeacoherentnotionevenifthemind-independent

existenceofkindsisnot;andthereisimportantworkherestillforrealiststodo.

Thisalsoclarifieshowarejectionofkindrealismmayfitintothelandscapesofbroader

realistdoctrinessuchasscientificrealism.13EarlierImaintainedthattheprincipalconnotationsof

kindconventionalismareconstructivismanddeflationism.Havingjustrevisitedthelatter,letme

concludewiththeformer.Therearedifferentformsofconventionalism.Therelevantnotionof

construction,recall,isthatofmakingacollectionofentitiesintoakindbyrecognizingitassuch;

thisrecognitionisconstitutiveofitsstatusasagenuinecategory.Clearly,therearesomeformsof

constructivismonwhichtherecanbenoknowledgeofanymind-independentfeaturesoftheworld

–inathoroughgoingKantianspirit,onemightholdthatthephenomenalworldweknowisan

inextricablemixofthenoumenalandthemental.Itisnonethelessopentoadifferentsortof

constructivistaboutkindstoholdthatsomeaspectsoftheworldarenotsoconstructed,andinthis

wayvindicateasobjectiveormindindependentthetruthorfalsityofscientific,indigenous,and

everydayclaimsaboutkinds.Isuspectthatformanywhowereoncekindrealistsbutshouldbeno

longer,thiswillberealismenough.

12Thoughnotalways:seeRuphy2010,pp.117-118,onrealismabouttaxonomicfeaturesversuscategories;Bird2018,pp.1398-1407,on‘weak’versus‘strong’realismaboutkinds,theformerassertingonlytheexistenceofnaturaldivisionsandthelatterthatkindsarepartoftheontologyoftheworld;andBrzovic(manuscript),pp.3-7,onrealismaboutwhatcompriseskindsversuskindsthemselves.13Foranaccounthowadeflationary,pluralisticapproachtokindsmaybeintegratedwithscientificrealism,seeChakravartty2007,chapter6.ForaradicallycontrastingviewseeEllis2009,chapter3.

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