View metadata, citation and similar papers at core.ac.uk brought to you by CORE provided by Springer - Publisher Connector StudEastEurThought(2016)68:63–74 DOI10.1007/s11212-016-9248-7 Kazimierz Ajdukiewicz on transcendental idealism from a semantic point of view Arkadiusz Chrudzimski1 Publishedonline:16February2016 (cid:2)TheAuthor(s)2016.ThisarticleispublishedwithopenaccessatSpringerlink.com Abstract In a paper entitled A Semantical Version of the Problem of Transcen- dental Idealism, Kazimierz Ajdukiewicz gives a very impressive analysis of tran- scendental idealism. He approaches the matter using the tools of formal semantics developed byAlfred Tarskianddraws arather surprisingconclusion. According to Ajdukiewicz,theidealistposition,claimingthattheworldaroundusisontologically dependent on our cognitive activity can be shown to be implausible on purely logical grounds. It is worth taking a closer look at this insightful argument, since Ajdukiewicz’s analysis, if sound, has a relevance reaching far beyond purely his- torical questions concerning the right interpretation and proper assessment of past idealistdoctrines.Thesedaysvariousspeciesof(mostlylocal)idealismarethriving undersuchlabelsas‘antirealism’or‘pragmatism’.Ajdukiewicz’svenerablepaper goes to the very core of many contemporary metaphysical discussions. Keywords Ajdukiewicz (cid:2) Tarski (cid:2) Go¨del (cid:2) Kant (cid:2) Idealism (cid:2) Semantics (cid:2) Syntax (cid:2) Truth (cid:2) Proof (cid:2) Justification (cid:2) Concept empiricism What is idealism Let me begin with an outline of the idealist position Ajdukiewicz targets in his paper. Ajdukiewicz addresses neo-Kantian versions, but for the contemporary reader it will be more convenient to focus on the better known Husserlian TheworkonthispaperwassupportedbythePolishNationalCentreofScience(NCN,Grant2012/07/B/ HS1/01595).Someparagraphsinsections‘‘Epistemictheoryoftruthandconceptualempiricism’’and ‘‘TarskiandKant’’(ca.15%ofthewholearticle)havebeentakenfromChrudzimski(2008). & ArkadiuszChrudzimski [email protected] 1 UniversityofSzczecin,Szczecin,Poland 123 64 A.Chrudzimski formulation. Beginning with the publication of the Ideas I1 Husserl sought to persuade us that the so-called ‘objective’ world is in point of fact a product of cognitive activity taking place in the transcendental consciousness. This cognitive activityHusserlcalls‘constitution’,andsotheclaimisthattheworldisconstituted by the pure transcendental consciousness. What exactly this pure transcendental consciousnessiswasneverentirelyclear,butinanyeventitissupposedtobeakind of residuum obtained by a sophisticated process of ‘purification’, starting with reflection on the totality of our mental acts and involving Husserl’s (in)famous transcendental reduction. The ‘content’ of the transcendental consciousness corresponds thus to the phenomena we find in our ‘impure’ mentality. We learn about presentations, judgments, sense-data, etc. The difference lies rather in how thiscontentistobeinterpreted:notasa‘natural’,‘objectified’processtakingplace in the natural world, but rather as something transcendental, responsible for all objectification and a fortiori for all we can find in the natural world. Now what does this constitution look like? Imagine you are perceiving a white horse on a green meadow. The first important observation, heard in every introductorycoursetophenomenology,isthatwhatwe‘reallysee’isonlyoneside ofthehorse.Well,inamundanesenseoftheword‘see’,weofcourseseethewhole horse, but in a more sophisticated, philosophically strict, phenomenological sense, itsbacksideisalwayshiddenfromourview.Whatwe‘really’seeisonlythefront sideoftheanimalinquestion.Thatwebelieveweperceivethehorseinitsentirety and not just one side has todo with nature of perception: in every perception quite complexoperationsaretacitlyperformed.Usually,wecanmovearoundandlookat thehorsefromdifferentangles.Werememberwhatwehaveseen,‘puttogether’the horse’s many sides, and treat them as belonging to a single object. Further, assumingthatwehaveasufficientlyrichfundofexperience,weevendon’tneedto move, for we remember that other horses have many visible sides, and we assume that the horse on the meadow we are actually looking at is in all general respects very similar to all the others we have experienced. All these operations—putting together successively inspected sides, treating remembered views as belonging to the same object, assuming that the general structureoftheactuallyperceivedobjectisingeneralverysimilartothestructureof the previously perceived ones—Husserl calls syntheses; and so his theory says that all composed objects of our cognition are synthesized from simpler data.2 As all adepts of phenomenology know, at the end of the day the theory of transcendental constitution gets very complicated, but happily there is no need to disentangleallitsfacetsinthispaper.Allwemustknowisthatconstitutionconsists in the application of certain transcendental norms,3 which are to be understood as epistemic rules stipulating that we are justified in believing certain contents on the 1 Cf.Husserl1913.Asiswellknown,Husserl’searlierworkswerenotintheidealistvein.Cf.aboveall hisPhilosophyofArithmetic(Husserl1891)andLogicalInvestigations(Husserl1900;Husserl1901). 2 These syntheses are for the most part ‘passive’. In contrast to such syntheses as explicit judging, comparingorcounting,they‘operateinthebackground’andwedon’tneedtoperformthemactively.Cf. Husserl1966. 3 HereisAjdukiewicz’sformulationofthemainidealistthesis:‘Astatementistrueifandonlyifitis dictatedbytranscendentalnorms.’(Ajdukiewicz1937:150). 123 KazimierzAjdukiewiczontranscendentalidealismfroma… 65 basisofdeterminatedata.Forexample,ifweexperiencethefrontsideofanobject, we can apply a certain rule (let’s call it ‘the three-dimensionality rule’) and obtain thebeliefthattheobjectinquestionhasothersidesaswell.Andifweobservethat theappearanceofthisobjectdoesn’tchangeveryrapidly,wecanapplyanotherrule (let’scallit‘thesubstancerule’)andobtainthebeliefthattheobjectinquestionhas acertain‘stablenature’thatdoesn’tchangewhentheobjectenduresintime,moves around,etc.Nowtheidealist’sclaimisthatobjectAexistsifandonlyifweareable tojustifyinthiswaythebeliefthatAexists.Theveryexistenceofobjectsbecomes in this sense a product of a coherent, systematic constitution.4 Ajdukiewicz’s semantic reformulation In his paper, Ajdukiewicz observes that this doctrine can be reformulated in semantic terms.5 Idealists prefer to use mentalist language. We hear about sense- data, presentations, judgments and beliefs. But it is possible—or so at least was Ajdukiewicz’s claim—to treat all this psychological talk as referring rather to expressions of a certain ideal language than to mental episodes. And the idealists’ insistence that their analysis doesn’t concern a ‘natural’, individual mentality, but rather a ‘pure’, ‘ideal’ or ‘transcendental’ consciousness, makes this conceptual shift even easier. What is essential is that we have here a certain system of representations that behaves in many important respects like a language. The most important point is that it must involve a kind of syntax that makes it possible to formulate and apply certain epistemic principles (corresponding to the norms of constitutionfromthelastsection).Ifweaccepttheideaofsuchareformulation,the idealist position begins to look like this: 1. Ourentiresystemofrepresentations(allthecontentofourpureconsciousness) can be treated as a kind of language. In particular it involves syntax defining what it means to be a well formed formula of this language. 2. There are some sentences of the language in question that we accept axiomatically. They correspond to the ‘data’ which build the starting point of the whole transcendental constitution. 3. There are certain purely syntactic rules by means of which we can prove sentences on the basis of other sentences. 4 Cf. the following statements from Husserl’s Ideas I: ‘Prinzipiell stehen in der logischen Spha¨re, in derjenigen der Aussage, ‘‘wahrhaft-’’ oder ‘‘wirklich-sein’’ und ‘‘vernu¨nftig ausweisbar-sein’’ in Korrelation;[…]Selbst-versta¨ndlichistdiehierinRedestehendeMo¨glichkeitvernu¨nftigerAusweisung nicht als empirische, sondern als ‘‘ideale’’, als Wesensmo¨glichkeit verstanden.’ (Husserl 1913: 314) ‘Prinzipiell entspricht […] jedem ‘‘wahrhaft seiendem’’ Gegenstand die Idee eines mo¨glichen Bewußtseins, in welchem der Gegenstand selbst origina¨r und dabei vollkommen ada¨quat erfaßbar ist. Umgekehrt, wenn diese Mo¨glichkeit gewa¨hrleistet ist, ist eo ipso der Gegenstand wahrhaft seiend.’ (Husserl1913:296). 5 Ku¨ng(1989: 155)observesthatAjdukiewiczapproachcan becomparedwithCarnap’spostulateof translatingphilosophical‘pseudo-problems’fromthematerialintoformalmodeofspeech.Cf.Carnap 1934. 123 66 A.Chrudzimski 4. The process of constitution consists basically in applying the rules (3) to the data (2) and to other sentences, provided they have been already proved.6 5. For object A to exist means that the corresponding existence claim— ‘A exists’—is demonstrable in the process (4). To avoid misunderstandings a few comments concerning the notion of ‘proof’ involved inthisreformulationwillbeinorder.Itgoes withoutsayingthat,inorder to obtain any plausible formulation, the rules (3) cannot be restricted to (i) purely deductiveprinciples.Inadditionwemusthavealso(ii)empirical,sometimescalled ‘inductive’ principles, and probably also (iii) a set of very rudimentary perception- rulesofthekind‘ifitseemstomethatIseethatp,thenIam(primafacie)justified in believing that p’. It should be also clear that the justificatory procedures employingrules(ii)and(iii)arefallible.7Somaybeitwouldbemoreappropriateto talk here about justifiability instead of demonstrability. Anotherimportantpointisthatthementioneddemonstrabilityorjustifiabilityistobe construednotasacontingentepistemicpositionthataparticularsubjectcanhavevisa` visaparticularpropositionataparticulartime,butratherassomethinglikean‘ideal’ justifiability: justifiability for an absolutely rational subject in an ideal epistemic situation‘inthelongrun’.Infact,idealistsoftenreferredexplicitlytoaninfinitechainof coherentconstitution,whichhadsurelytodowiththefallibilityofmanyoftheprinciples involved.Inparticular,Husserlstressedthattheexistenceofaphysicalthingcanbeonly understood as a Kantian idea—a correlate of an infinite process of coherent constitution.8ItseemsthusthatanAjdukiewicz-stylereformulationoftherealidealist doctrinesshouldinanyeventallowforinfinitistmethodsofproof.9 Application of Tarski’s results Rephrasing traditional philosophical puzzles in linguistic terms is a technique that has often been used in the tradition of analytic philosophy. In general, analytic philosophers tend to believe that such a reformulation is a good way to gain clarity.10 But for Ajdukiewicz the reformulation of the idealist doctrine as a thesis 6 Ajdukiewiczsaysthatinsteadofdistinguishingbetween(2)and(3)itwouldalsobepossibletousethe rulesofinferenceonly.Whatwehavetodoisonlytospecifythatcertainsentences(correspondingtoour axioms)arederivablefromtheemptysetofpremises. 7 Cf.Chisholm1989(particularlyontherulesofthethirdkind). 8 Cf. ‘Es bleibt also dabei, daß das Eidos Wahrhaft-sein korrelativ gleichwertig ist mit dem Eidos Ada¨quat-gegeben- und Evident-setzbar-sein - das aber entweder im Sinn endlicher Gegebenheit oder GegebenheitinFormeinerIdee.IneinemFalleistdasSein‘‘immanentes’’Sein,Seinalsabgeschloßenes Erlebnis oder noematisches Erlebniskorrelat; im anderen Falle transzendentes Sein, d.i. Sein, dessen ‘‘Transzendenz’’ eben in der Unendlichkeit des noematischen Korrelats, das es als Seins‘‘materie’’ fordert,gelegenist.’(Husserl1913:298). 9 Whichwouldcausesome problemsforthe applicationofGo¨del’sresults.I thankJanWolen´skifor bringingthistomyattention. 10 Althoughitisahugefallacytoseeanalyticphilosophyasgenerallycommittedtothisprinciple.Many analytic philosophers approach philosophical problems directly, without any syntactic or semantic reformulation. 123 KazimierzAjdukiewiczontranscendentalidealismfroma… 67 aboutalanguage-likerepresentationalsystemwasofaspecialimportance.Hisidea was to directly apply the results obtained by Alfred Tarski, and, as is well known, they were formulated for languages of a certain kind. An important result of Tarski’s analysis of the concept of truth was that, for any language that is rich enough to contain elementary arithmetic, the concept of truth cannot be equated with the concept of provability (see Tarski 1933 and, less technical, Tarski 1969). TheeasiestwaytoseehowthisworksistorefertoGo¨del’sfamousexampleused in his demonstration of the incompleteness of arithmetic (see Go¨del 1931). Put informally, what Go¨del did was to show that in the language of arithmetic one is able to construct a sentence saying of itself that it cannot be proved. The crucial pointisthattheconceptofproofasapurelysyntacticalconcept11canbeexpressed in the same language provided the language in question is rich enough to contain elementary arithmetic. Soassumewehavebeforeusasentencesayingofitselfthatitcannotbeproved. Whatshouldwedowithit?Itsfalsitywouldmeanthatitisprovable(sinceitclaims precisely that it isn’t), and it is not hard to see that this possibility is not very tempting. The consequence being that we would have in our system provable falsities and this is definitely the last thing we wish. It seems thus that the only sensible option is to claim that Go¨del’s sentence is true, which in turn means that there are certain non-provable truthsand therefore the concepts oftruth andthatof provability are two quite different concepts—two concepts that are not even materially equivalent (i.e. not even co-extensional). Nowlet’sgobacktoTarski.Hismostfamousthesiswasthattheconceptoftruth for a (reasonably rich) language L cannot be expressed in the language L itself. Whatweneedisameta-languageL’withconsiderablyricherresources.Thismeta- language should contain three parts: (i) a ‘syntactic’ part that allows us to refer to the expressions of L (involving e.g. structural names of L’s sentences); (ii) apart by means of which we can speak about the objects belongingtoL’s universe of discourse (in the simplest case L’ can be thought of as containing the whole of L as its part); and finally (iii) the semantic vocabulary expressing concepts like truth, reference etc. With these resources at hand we can build ‘a formally correct and materially adequate definition of truth’. According to Tarski, a materially adequate definition of truth—i.e. a definition that does justice to the broadly Aristotelian, realist intuition that the truth of a sentence consists in a certain relation to reality—must, for any sentence ‘p’ generate a corresponding T-sentence12 of the following form: 11 Therulesofproofarepurelysyntacticalinthesensethattheyreferonlytothesyntacticpropertiesof theinvolvedexpressionandnottotheirmeaningorreference. 12 Bytheway,thename‘T-sentence’wasn’tderivedfrom‘Tarski’butfrom‘truth’. 123 68 A.Chrudzimski (T) ‘p’ is true if and only if p.13 And the most important condition of its formal correctness is the requirement that the semantic predicates like ‘is true’, that can be applied to the sentences of L, cannotbelongtothesamelanguageL.Otherwisewewouldbeabletoconstructthe (in)famous liar sentence: (*) The sentence (*) is not true, and our theory would end in paradoxes. Now what are consequences of this for the problem of transcendental idealism? As we have seen in section‘‘Ajdukiewicz’s semantic reformulation’’ an idealist claims that the whole content of the real world is defined by the rules of epistemic justification. We know that the set of rules she takes into consideration goes far beyondthedeductiverulesofproofTarskiandGo¨delwereconcernedwith,butthe crucial point is that all these rules are—exactly like the deductive ones—purely syntactic. They refer only to the syntactic structure of representations, not to their semantic properties. In this sense an idealist is trying to define truth in purely syntactic terms which, as Tarski has shown, is bound to fail.14 Inalaterpaperfrom1948,entitled‘‘EpistemologyandSemiotics,’’Ajdukiewicz takes a slightly different route. In this paper he targets Berkeley’s claim ‘esse est percipi’ and argues that it amounts to operating with a meta-language of syntax deprived of any means of referring to the objects belonging to the universe of the object-language. Also here Ajdukiewicz begins with translating the original mentalist language into the statements about a language-like representational system. An idealist who, like Berkley, defines things as ‘clusters of ideas’ equates them in fact with complexes of representations described purely syntactically. Recalling the three parts that have to be contained in Tarski’s meta-language, namely (i) a ‘syntactic’ part referring to the expressions of the object-language L, (ii) a part by means of which we can speak about the objects belonging to L’s universe of discourse, and (iii) the semantic vocabulary expressing concepts like truth, reference, etc., we see that Berkeley’s conceptual resources are clearly restricted to (i). The outcome of this analysis is similar to the conclusion of Ajdukiewicz’searlierpaper.Anidealistwhorestrictsherselftoameta-languageof syntaxisboundtounderstandtruthandreferenceinpurelysyntacticterms,which— as we have seen—is not a very good idea.15 13 InTarski’soriginalformulationthenamesofsentencesarenotformedbyquotationmarks,butinstead structural names are used. These details are very important for the formal correctness of Tarski’s analysis,buttheyneedn’tconcernushere. 14 InChrudzimski2008,IarguethatIngarden’sresistancetoHusserl’stranscendentalidealismmaywell havebeenstrengthenedbyhisacquaintancewithTarski’swork.WeknowthatIngardenheardTarski’s summaryofhistheoryoftruthinPolishPhilosophicalSocietyin1930.Cf.Tarski(1995:8),wherewe readthatIngardentookpartinthediscussionfollowingTarski’spresentation. 15 InAjdukiewicz’spapersfrom1949-50,entitledOntheNotionofExistence,wefindanotherinteresting analysisofidealism.HereAjdukiewiczappliesLes´niewski’slogicalsystems.SeeKu¨ng1989:160ff. 123 KazimierzAjdukiewiczontranscendentalidealismfroma… 69 Epistemic theory of truth and conceptual empiricism Well, this result is doubtless interesting on its own, but does it also have any systematicvaluebeyondjustonemore,evenifparticularlyimpressive,refutationof idealism? If it were no more than this, then Ajdukiewicz’s paper would be at most historicallyinteresting,for,tobehonest,whenwasthelasttimeyoucameacrossan idealist? If we look at a philosopher’s explicit declarations, then idealism as a philosophical option doesn’t seem to be very popular. But fortunately for the actuality of Ajdukiewicz’s analysis (although maybe unfortunately for the reputation of philosophy as a serious intellectual activity), it turns out that there are still quite a few active idealists among us. The trick is that they seldom call themselves by their true name, using instead various misleading labels, such as ‘antirealism’ or ‘pragmatism’. What they all have in common is a strong tendency to define truth in epistemic terms and this is, as we have seen, the main disease of idealism as Ajdukiewicz saw it. Of course the sole fact that a philosopher has some problems with the Aristotelian understanding of truth doesn’t by itself imply that he or she is an idealist. In fact, there have been many philosophers who expressed reservations about this construal of truth and some, like e.g. Franz Brentano, did not evince the slightest idealist tendency. It must also be conceded that before Tarski’s works excellent reasons were available for regarding the Aristotelian idea with suspicion. Before Tarski succeeded in demonstrating how the realist, Aristotelian concept of truth could be coherently explicated it was very easy to think that it is irreparably paradoxical and should be abandoned.16 Nonetheless typical arguments against the Aristotelian view involved something more than a hint of the logical predicament illustrated by the liar sentences. Normally they have revolved around the idea that a realist concept of truth unsupplementedbysomeepistemicrulesofapplication,simplycouldn’tfunctionas an element of our cognitive system. Franz Brentano also argued in this way (cf. Chrudzimski 2001a: 71ff), but here let me cite two contemporary examples. In his book Pragmatism: An Open Question Hilary Putnam writes: To say that truth is ‘correspondence to reality’ is not false but empty, as long asnothingissaidaboutwhatthe‘correspondence’is.Ifthe‘correspondence’ is supposed to be utterly independent of the ways in which we confirm the assertions we make (so that it is conceived to be possible that what is true is utterly different from what we are warranted in taking to be true, not just in some cases but in all cases), then the ‘correspondence’ is an occult one, and our supposed grasp of it is also occult. (Putnam 1995: 10) In a similar vein Michael Dummett argues that: 16 AgoodexampleofthisattitudeisKarlPopper(1934).Itiswellknownthat,afterreadingTarski,he became one of the greatest friends of the realist concept of truth, though earlier, in his Logik der Forschung,hecautiouslyavoidedemployingtheconcept. 123 70 A.Chrudzimski thenotionoftruth,whenitisintroduced,mustbeexplained,insomemanner, intermsofourcapacitytorecognizestatementsastrue,andnotintermsofa condition which transcends human capacities. (Dummett 1976: 116) The assumption behind these declarations seems to be that a grasp of any concept essentially involves a grasp of some criteria of its application. Consequently a concept totally devoid of such criteria would be essentially ungraspable, which is ratherbadnews,sinceitseemsthataconceptthatisessentiallyungraspabledoesn’t deserve the name of concept in the first place. But what could be the reason to think that every concept indeed necessarily involvessuchepistemiccriteriaofapplication?Itcanbeconcededthatthisclaim— let’s call it the criterial theory of concepts—has a certain initial plausibility. For manyconceptslike‘beingahorse’,‘havingaheadache’,or‘enjoyingfootball’there arewithoutdoubtsuchcriteria,andwetendtoassumethatforallotherconceptsthe situation is similar. But when confronted with the realist concept of truth, doubts arise.Afterall,AristotleandTarskiseemtohavebeenquitesensibleandreflective human beings; both believed themselves to understand this concept perfectly. Is it reallywisetothinkofthemasbeingdeeplyconfused—totreatthemasvictimsofa sophisticated conceptual illusion, instead of simply restricting the scope of the criterial theory of concepts? Why can we not say that certain concepts (amongst them the realist concept of truth) just don’t involve any criteria of application? Is thereanyindependentjustificationforanunrestrictedreadingofthecriterialtheory of concepts? It seems that the further assumption, one that plays an important role in generatingtheepistemicapproachtotruthwearetalkingabout,issomethingwecan call an unrestricted concept empiricism. The claim is that all our concepts ‘derive from experience’, a claim we find both in Aristotle and in the works of British empiricists like Locke and Hume. Franz Brentano defended it vigorously against Kant’sapriorism,andalsoHusserl’stheoryofconstitutionisa(rathersophisticated) version of this view (see Chrudzimski 1999). According to the traditional version of this view our concepts can be acquired only in the following ways: (i) a concept can be either ‘abstracted’ from the direct data of experience or (ii) it can be ‘constructed’ from the elements previously abstracted in the above mentioned way. Sometimes it is also assumed that (iii) conceptual elements can be further idealized in order to obtain such concepts as materialpoint,frictionlessmovementoridealvacuum.Beyondtheseproceduresof abstraction,combination,andidealizationthereisnootherwaybymeansofwhich a human being can acquire a concept. Thispositionseemstobeperfectlyconsistentformanyofourordinaryconcepts. The catastrophe happens when a concept empiricist wants to be so consistent as to extend his empirical treatment to the concept of truth as well; and this is precisely what many philosophers do. Imaginethatweacquireourconceptoftruthinoneoftheaforementionedways. Inthiscasetheremustbesomekindofexperienceinwhichtruthpresentsitselfand from which the concept of truth can be abstracted; or there must be at least some experiences from which we can abstract the essential elements of this concept that 123 KazimierzAjdukiewiczontranscendentalidealismfroma… 71 could be thereafter (possibly after some process of idealization) mentally ‘put together’ to build our concept of truth. Thereasonwhyaconceptempiricisttypicallyfindstherealistdefinitionoftruth non-intelligible becomes clear when we ask ourselves what kinds of experiences must be postulated to satisfy this requirement. Recall that the realist definition introduces a relation between a judgement (or belief) and some parts or aspects of reality. If my judgement that a cat is on the mat is true, then there must be in the external mind-independent world a cat on the mat. We have here a kind of comparison between a mental state (judgement, belief) and some pieces of reality (structured objects, tropes, state of affairs or something else, depending on our favourite theory of truthmaking). Now according tothe thesis of concept empiricism we could conceptually grasp such a relation only if we claim to have an experience from which we are able to abstract both of its terms. With the cognitive access to our mental states there will beingeneralnoproblem.MostidealistshavebeenCartesiansinthattheybelieved that we are able to reach our mental states cognitively in a particularly direct and epistemicallysecureway.Butwhataboutthe‘piecesofreality’thataresupposedto constitute the second term of the adaequatio relation? The sad truth is that we can access them cognitively only ‘through’ a mental state, namely through a corresponding justified belief. Indeed, to have an experience that a cat is on the matisnothingoverandabovehavingajustifiedbeliefthatacatisonthemat(where the justification involved has a particular ‘perceptual’ character). The crucial point here is that a justified belief is essentially (and not merely contingently)theonly wayinwhich we canbecognitively acquainted with apiece of the mind-independent world; and this means that within the framework of concept empiricism we are principally unable to separate the relevant pieces of reality from the mental states in which they are given to us. What we are able to abstractfromourexperiencesinwhich‘thetruthrevealsitselftous’isthusonlythe conceptofajustifiedbelief.Thebest wecan dois therefore tocompare ourbeliefs with other properly justified beliefs and the only concept of truth we can have is consequentlytheconceptofanidealizedjustifiability.Thisis,inanutshell,atypical argument leading to the epistemological construal of truth, and we end with the claim that: truthisanidealizationofrationalacceptability.Wespeakasifthereweresuch things as epistemically ideal conditions, and we call a statement ‘true’ if it would be justified under such conditions (Putnam 1981: 55). There are various possible reactions to this kind of argument: 1. Wecanacceptitasitstandsandabandontheveryideaoftherealistconceptof truth,assomethingthatis‘forconceptualreasons’principallyungraspable.The naturaloutcomeofthisreactionwillbesomeversionoftheepistemicdefinition of truth. This was e.g. the way of Franz Brentano. 2. We can try to reconcile the realist construal of truth with the thesis of concept empiricismbyfinding(orinventing)akindofexperienceonthebasisofwhich 123 72 A.Chrudzimski the concept of adaequatio can be abstracted or constructed. This was Anton Marty’s reaction (cf. Chrudzimski 2001c). 3. Finally,wecaninterprettheaboveargumentationasareductioadabsurdumof its premises and claim that the premise which has to be rejected is the very thesis of concept empiricism (at least in its general, unrestricted form). Tarski and Kant Ihappentothinkthatthelastreactionistherightone.ItleadsustoapositionthatI want to term concept Kantianism. A partisan of this position is committed to the claim that not all of our concepts ‘derive from experience’ and the most important ofthosenon-empiricalconceptsistherealistconceptoftruth(cf.alsoChrudzimski 2001b). As we remember, one of the central features of Tarski’s analysis was that a formally correct definition of truth cannot be expressed in the object language L. What we need is an essentially stronger meta-language L’. An important consequenceofthistreatmentisthattherecouldbenodefinitionoftruthsimpliciter. WecanspeakonlyofadefinitionoftruthforagivenlanguageL,whichcanonlybe formulated within the framework of a stronger meta-language L’. In order to formulate a corresponding definition of truth for L’ we have to move one level higher,toastillstrongermeta-meta-languageL’’,tospeakoftruthinL’’wehaveto introduce L’’’, etc. These limitations can be regarded as a very good explication of the difficulties that all concept empiricists have with the classical concept of truth. What is to be expected is namely that the very idea of splitting our representational scheme into an open-ended hierarchy of meta-languages, which is required by any Tarski-style explication,issomethingwhich noconceptempiricistcouldbeveryhappy with. If allourconceptsareabstractedfromsomehomogenouslevelofthebasicdata,then it seems to be principally inexplicable how a meta-language (which according to conceptempiricist principlesprobablyhas tobeconstruedasaproductofacertain higher-orderabstraction)caneveracquireconceptualresourcesthataresignificantly stronger than its abstraction basis. What we would expect is rather that a concept empiricist will tend to understand the totality of our conceptual resources as one homogenous ‘language of thought’. Nonetheless, the work of Tarski seems to show that our conceptual scheme at leastcanberegimentedthisway,sothattheAristotelianideacanbeexpressedina perfectly intelligible form. Since Tarski, there is therefore strong evidence for the concept Kantianism relative to the concept of truth, and the burden of proof falls definitely on the partisans of the unrestricted concept empiricism. Itseemsthereforethatwehavegoodreasonstoregardtherealistconceptoftruth as a ‘Kantian’ concept in the sense that it doesn’t seem to be derivable from experience. Ifwe graspthisconceptatall–andTarski’sbrilliantanalysissuggests stronglythatweindeeddo—thenitmustbeaprioriinKant’ssense.Butthisisnot the end of the story, because the realist concept of truth deserves the name of a 123