FRIEDMAN & BIRD- Kantian Themes in Contemporary Philosophy

8/18/2019 FRIEDMAN & BIRD- Kantian Themes in Contemporary Philosophy

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KANTIAN THEMES IN CONTEMPORARYPHILOSOPHY

Michael Friedman and Graham Bird

I—Michael Friedman

ABSTRACT This paper considers the extent to which Kant’s vision of adistinctively ‘transcendental’ task for philosophy is essentially tied to his viewson the foundations of the mathematical and physical sciences. Contemporary

philosophers with broadly Kantian sympathies have attempted to reinterpret hisproject so as to isolate a more general philosophical core not so closely tied to thedetails of now outmoded mathematical-physical theories (Euclidean geometry andNewtonian physics). I consider two such attempts, those of Strawson andMcDowell, and argue that they fundamentally distort the original Kantian impulse.I then consider Buchdahl’s attempt to preserve the link between Kantianphilosophy and the sciences while simultaneously generalizing Kant’s doctrinesin light of later scientific developments. I argue that Buchdahl’s view, while notadequate as in interpretation of Kant in his own eighteenth century context, isnonetheless suggestive of an historicized and relativized revision of Kantianismthat can do justice to both Kant’s original philosophical impulse and the radical

changes in the sciences that have occurred since Kant’s day.

ant begins the Critique of Pure Reason with the distinctionK between empirical knowledge and pure or a prioriknowledge. He points out that metaphysics has always aimed atthe latter type of knowledge and, indeed, at knowledge that‘extends the sphere of our judgements beyond all limits of experience’ (A3/B6). 1 Metaphysics has here taken inspiration

from the example of mathematics, but in doing so, Kant suggests,metaphysics has also been fundamentally misled. Whereas thelatter science has been so far occupied chiefly with analysis, withwhat ‘has already been contained in our concepts (althoughconfusedly)’, the former science essentially goes beyond mereconcepts, in that ‘it occupies itself with objects and cognitionssolely in so far as they can be presented in intuition’ (A4–6/B8–9). And since only the latter type of a priori knowledge, synthetic

as opposed to analytic a priori knowledge, genuinely extends therange of our cognition, metaphysics, if it, too, hopes to ‘extend the

1. All references to the Critique of Pure Reason are given parenthetically in the text by thestandard pagination of the first (A) and second (B) editions respectively.


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112 I—MICHAEL FRIEDMAN

sphere of our judgements’, requires a preliminary inquiry into thenature, scope, and limits of our synthetic a priori knowledge. Thepreliminary inquiry in question is then precisely the task of the

Critique , and only in this way, Kant holds, can philosophy ormetaphysics finally enter into the secure path of a science.With this articulation of the peculiar task of what Kant now calls

‘transcendental philosophy’, the subject matter of philosophy has,for the first time, been clearly delimited from that of the naturaland mathematical sciences, and, in particular, from those elementsof a priori knowledge present in the latter sciences themselves:

[N]ot every a priori cognition should be called transcendental, but

only that through which we know that and how certain represent-ations (intuitions or concepts) are applied wholly a priori, or arepossible (that is, [through which we know] the possibility or the apriori employment of the cognition). Therefore, neither space norany a priori geometrical determination thereof is a transcendentalrepresentation, but what can alone be called transcendental is theknowledge that these representations are not at all of empiricalorigin, and the possibility that they can nevertheless relate a priorito objects of experience. (A56/B80)

I term all cognition transcendental which occupies itself in general,not so much with objects, but rather with our mode of cognition of objects, in so far as this is supposed to be possible a priori. (B25)

Transcendental philosophy is thus a meta-discipline, as it were,whose distinctive task is to investigate the nature and conditionsof possibility of first-level scientific knowledge.

Contemporary philosophers dissatisfied with the prevailingtendency to ‘naturalize’ their discipline by incorporating philo-sophy, too, among the natural sciences are therefore under-standably drawn back to the philosophy of Kant, who thus firststaked out the claim to a distinctive, ‘transcendental’ task lyingoutside the domain of the first-level sciences themselves. When itcomes to the details of Kant’s own transcendental program,however, such contemporary philosophers immediately run intoapparently insuperable difficulties. For Kant makes it very clearthat his inquiry breaks down, more specifically, into the two

questions ‘How is pure mathematics possible?’ and ‘How is purenatural science possible?’—where the first concerns, above all, thepossibility of Euclidean geometry, and the second concerns thepossibility of fundamental laws of Newtonian physics such as


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KANTIAN THEMES IN CONTEMPORARY PHILOSOPHY 113

conservation of mass, inertia, and equality of action and reaction(B19–21). Now, however, we no longer believe that these specificKantian examples of synthetic a priori knowledge are even true,

much less that they are necessarily and a priori true. Indeed, forprecisely this reason, we are no longer convinced that there are anyreal examples of synthetic a priori knowledge at all. So it seemsthat we cannot now follow Kant in even his very first step in furtherarticulating what the distinctively transcendental task of philo-sophy is supposed to be.

It is also understandable, then, if contemporary philosopherswith broadly Kantian sympathies attempt to reinterpret his project

so as to isolate a more general philosophical core not so closelytied to the details of now outmoded mathematical-physicaltheories. And it is similarly understandable, further, if suchphilosophers attempt to break the intimate link between Kantiantranscendental philosophy and problems in the foundations of mathematics and physics by reorienting Kant’s transcendentalargumentation towards much more general philosophicalproblems, which, it is hoped, can be pursued largely independently.

In particular, by thus separating a more general core from its morevulnerable accompanying parts, now seen as inessential, we mighthope to rehabilitate Kant’s claim to a distinctive task forphilosophy in the face of the contrary ambitions of contemporaryphilosophical naturalism.

I

No-one within the analytic tradition has done more to reawakeninterest in Kantian transcendental philosophy than P. F. Strawson.In his classic essay, The Bounds of Sense , Strawson sets out toeffect a separation or division ‘between what remains fruitful andinteresting [in Kant’s Critique ] and what no longer appearsacceptable, or even promising, in its doctrines.’ 2 Among the‘obstacles to sympathetic understanding’, of course, is ‘the stateof scientific knowledge at the time at which Kant wrote’, whichinclined him, in particular, to a belief in ‘the finality of Euclideangeometry, Newtonian physics, and Aristotelian logic’. 3 Strawson’s

2. P. F. Strawson, The Bounds of Sense (London: Methuen, 1966), p. 16.3. Op. cit ., p. 23.


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aim, accordingly, is to abstract out a more general core of Kantiandoctrine, which, in his own words, attempts to articulate the‘necessary conditions of the possibility of experience in general’

rather than simply the ‘necessary presuppositions of physicalscience’. 4 These ‘necessary conditions of the possibility of experience in general’, freed of any dependence on the specificsof scientific theorizing, will then be independent of the changesand vicissitudes that such theories have actually undergone in thesubsequent history of the sciences.

The defensible core of Kantian doctrine is thus devoted to whatStrawson calls ‘the metaphysics of experience’, where ‘Kant

attempts to show what the limiting features must be of any notionof experience which we can make intelligible to ourselves.’ 5Prominent among these limiting features are that, in virtue of what‘is required for the possibility of self-consciousness’, ‘experiencemust include awareness of objects which are distinguishable fromexperiences of them’, that, as a further consequence, ‘there mustbe one unified (spatio-temporal) framework of empirical realityembracing all experience and its objects’, and, finally, ‘that certain

principles of permanence and causality must be satisfied in thephysical or objective world of things in space’. 6 The spatio-temporal framework in question, however, is not further limited bythe constraints of any particular mathematical-physical theory: itis not limited to specifically Euclidean space, for example, or tothe structure of Newtonian, as opposed to relativistic, physics. Norare the principles of permanence and causality to which Strawsonrefers identical to the strong Newtonian principles of conservation

and thoroughgoing causal determination that Kant actuallydefends; on the contrary, we require only relatively, as opposed toabsolutely permanent ‘re-identifiable objective items’ subject tomore or less regular ‘law-like expectations’. 7

In this way, far from being limited to describing the foundationsor necessary presuppositions of the mathematical and physicalsciences of Kant’s day, the defensible core of Kant’s trans-cendental argumentation has a much more general philosophical

4. Op. cit ., p. 121.5. Op. cit ., p. 24.6. Ibid .7. Op. cit ., p. 146.


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aim: namely, to show that the impoverished conception of experience of the classical empiricist ‘sense-datum theorist’,according to which our experience is confined, at least initially, to

the veil of perception of our own subjective sense impressions, isnot in fact intelligible. And it is precisely this conception of experience, of course, which sets the stage for the classicalsceptical arguments of the modern period. Such arguments, if thedefensible core of Kant’s transcendental argumentation is correct,operate with an entirely incoherent conception of an initial, purelysubjective experience, which, in particular, fails to make roomeven for the self-conscious subject that is supposed to be the bearer

of this experience. Therefore, if the argumentation in question iscorrect, we will have made decisive progress in the defense of ourcommonsense conception of experience and the world from thestrictures of philosophical scepticism.

Now this Strawsonian reconstruction of the defensible core of the Critique has spawned an extensive literature on the preciseanti-sceptical force of what are now known as ‘transcendentalarguments’. Perhaps the most important point in this context hasbeen made in a well-known paper by Barry Stroud, 8 according towhich the most such arguments can prove is that our overallconceptual scheme must possess certain features (here, theconception of an external world subject to constraints of permanence and regularity) on pain of incoherence. They do notand cannot show, however, that such features and conceptions mustactually be correct (that there really is in external worldconforming to these constraints, for example), and, in this sense,their anti-sceptical force is severely limited. Strawson, inresponding to Stroud’s challenge, has fully acknowledged thispoint: the role of such transcendental arguments is solely to show‘that one type of exercise of conceptual capacity is a necessarycondition of another’, so that their precise philosophical force issimply to articulate necessary conceptual connections within ourconceptual scheme. The peculiarly philosophical task of

Strawsonian ‘descriptive metaphysics’, then, is to exhibit thenecessary structure of our conceptual scheme, which is thereby

8. B. Stroud, ‘Transcendental Arguments’, The Journal of Philosophy , Vol. LXV, No. 9,May 1968.


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depicted as ‘a coherent whole whose parts are mutually supportiveand mutually dependent, interlocking in an intelligible way’. 9

What, more precisely, is the nature of the necessary conceptual

connections we are thus attempting to delineate, and what, morespecifically, is the character of the peculiarly philosophicalenterprise wherein such delineation takes place? In The Bounds of Sense Strawson firmly rejects both Kant’s conception of synthetica priori truth and his conception of the transcendental philosophicaltask of explaining the possibility of such truth. But to the questionof what alternative conception might be offered, Strawson isremarkably noncommittal:

To this I can only reply that I see no reason why any high doctrineat all should be necessary here. The set of ideas, or schemes of thought, employed by human beings reflect, of course, their nature,their needs and their situation. They are not static schemes, butallow of that indefinite refinement, correction, and extension whichaccompany the advance of science and the development of socialforms.... But it is no matter for wonder if conceivable variations areintelligible only within a certain fundamental general framework of ideas, if further developments are conceivable only as

developments of, or from, a certain general basis. 10

The question as to the precise nature of the peculiarly philo-sophical enterprise, wherein we attempt to articulate ‘what thelimiting features must be of any notion of experience which wecan make intelligible to ourselves’, is here rather abruptlydismissed.

In Skepticism and Naturalism , however, Strawson returns to this

question, and in a way, I believe, that is particularly revealing.Prompted largely by Quine’s attack on the very notion of a specialrealm of necessary conceptual connections, Strawsonacknowledges that there is indeed a philosophical problem aboutthe character of ‘abstract and general thinking which at leastappears to concern itself directly with concepts or universals, asin philosophy itself, or with other abstract objects, as inmathematics’. 11 The kind of ‘hard naturalism’ represented by

Quine rejects the existence of a peculiar domain of ‘objective9. P. F. Strawson, Skepticism and Naturalism (New York: Columbia, 1985), pp. 22–23.10. The Bounds of Sense , p. 44.11. Skepticism and Naturalism , p. 86.


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mathematical or conceptual truth’ as falling entirely outside thepurview of modern empirical natural science. But it is also possibleto endorse a ‘soft naturalism’, Strawson urges, in which we simply

accept our apparent capacity for insight into such truths as suigeneris , thereby falling in with the classical philosophical traditionof ‘rational intuition’. We thereby endorse ‘as Descartes wouldsay, the power of “clear and distinct perception” of necessarytruths; or, as both he and Spinoza would say, the power of “rationalintuition” of such truths’. 12

It is not my purpose to argue against this last Strawsoniansuggestion, but I do want to emphasize how profoundly unKantian

it is. For Strawson here aligns himself with the classical rationalisttradition which Kant himself explicitly rejects. Indeed, from aKantian point of view, Strawson is here fundamentally ‘uncritical’in several interrelated respects. In the first place, ‘conceptual truth’in philosophy is intimately associated with mathematical truth,even though, as Kant himself emphasizes, mathematics has longsince attained ‘the secure path of a science’, whereas philosophyis very far from doing so (Bx–xv). In the second place, necessaryor a priori truth in general is conceived as the product of a facultyof ‘clear and distinct perception’ or ‘rational intuition’, and thusas secured by a special kind of quasi-perceptual acquaintance witha particular domain of ‘objects’. The whole point of Kant’s‘Copernican revolution’ in thinking about the a priori, by contrast,is to break decisively with this classical tradition. Necessary or apriori truths, in mathematics, for example, have no special domain

of objects at all; their characteristic status derives rather from theirconstitutive function with respect to ordinary empirical objects(viz., ‘appearances’): their function, namely, of making empiricalknowledge of such empirical objects first possible. 13 Finally, andcorrelatively, the peculiar role of philosophy, from a Kantian pointof view, rests neither on a special faculty of ‘rational intuition’ noron the construction of a priori truths constituting the necessarypreconditions of empirical knowledge that we find in mathematics.

Philosophy functions rather on a higher or meta-level, as it were,12. Op. cit ., p. 91.13. See especially §22 of the second edition Transcendental Deduction, and compareA146/B185.


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where our task is precisely to explain how such first-level a prioriknowledge is possible.

II

A more recent attempt at importing central Kantian themes intocontemporary philosophical discussion is John McDowell’s Mind and World ,14 which, as McDowell points out, is very stronglyinfluenced by Strawson’s reading of Kant in The Bounds of Sense .Instead of focusing on the problem of philosophical scepticism,however, and the Strawsonian project of delineating, in response,the minimal necessary conditions of any intelligible experience,McDowell concentrates rather on the fundamental Kantiandistinction between concepts and intuitions, understanding andsensibility, spontaneity and receptivity. For McDowell, Kant’smost important insight is that understanding and sensibility,spontaneity and receptivity, must always be integrated together.There is no room, in particular, for either unconceptualizedsensory input standing in no rational relation to conceptualthought, or purely intellectual thought operating entirelyindependently of all rational constraint from sense experience:‘Thoughts without content are empty, intuitions without conceptsare blind’ (A51/B75). And it is only by fully assimilating thisKantian insight, according to McDowell, that we can escape theotherwise interminable philosophical dialectic or oscillationbetween Coherentism and the Myth of the Given: the temptation,on the one hand, to picture the understanding as a self-containedconceptual sphere with no rational relation to an independentempirical world, or, on the other, to invoke bare unconceptualizedsensory presences acting on the understanding from outside theconceptual sphere.

In response to this philosophical dialectic, McDowellrecommends an alternative picture of sensible experiences,products of our receptivity, as nonetheless thoroughly infused withconceptual content: ‘In experience one takes in, for instance sees,that things are thus and so . That is the sort of thing one can also,for instance, judge.’ 15 In this way, ‘experiences themselves are

14. J. McDowell, Mind and World (Cambridge: Harvard, 1994).15. Op. cit ., p. 9.


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states or occurrences that inextricably combine receptivity andspontaneity.’ 16 Sense experiences belong to our spontaneity, thesphere of the understanding, in virtue of their conceptual content:

their expressibility in a that-clause. Unlike acts of judgement,however, sense experiences also belong to our receptivity, in thatwe are passively presented with the world’s appearing to be thusand so rather than actively judging (perhaps after reflectivelydeciding whether to accept this appearance or not) that the worldis in fact thus and so. Hence, although passively received sensibleexperiences belong, in virtue of their content, to the conceptualrealm, there remains a fundamental distinction between such

experiences, on the one side, and acts of judgement or belief, onthe other. We thereby retain the crucial idea of independentconstraint from outside the realm of our judgements and beliefs,without falling into the temptation to invoke bare unconceptualizedsensory presences acting on the understanding from outside theconceptual sphere.

McDowell’s most basic Kantian legacy, therefore, is the idea of a necessary and thoroughgoing interdependence between thespontaneity of the understanding and the receptivity of sensibility.And it is just such a necessary interdependence that Kant himself attempts to establish in the Transcendental Deduction of theCategories, whose aim is precisely to show that ‘[sensible]appearances have a necessary relation to the understanding ’(A119), so that ‘the two extremes, namely sensibility andunderstanding, must stand in necessary interconnection’ (A124).McDowell’s own way of defending the necessary interconnectionin question, however, does not appeal to a transcendentaldeduction. Instead, in accordance with a broadly Wittgensteinianphilosophical ‘quietism’, McDowell rather attempts to remove theobstacles standing in the way of fully assimilating the Kantianinsight by providing us with a diagnosis of the intellectualdifficulties that actually give rise to the opposing philosophicaltemptations.

The key obstacle standing in the way of a proper appreciationof the Kantian insight, according to McDowell, is the‘disenchantment’ of nature effected by the scientific revolution.Before the scientific revolution nature was seen as itself ‘filled

16. Op. cit ., p. 24.


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with meaning’, and thus as perfectly hospitable to the similarlymeaningful structure of the normative ‘space of reasons’governing our understanding. After the scientific revolution,

however, nature was seen as a mere ‘realm of law’, which, inparticular, is thereby radically external to the meaningfulnormative structure governing our understanding. 17 Sensibility, bycontrast, clearly and incontrovertibly belongs to the domain of nature; it belongs to our nature as perceiving organisms receivingsensory impacts from the external natural world. But it thenbecomes entirely mysterious, on the modern conception of disenchanted nature, how sensibility and understanding can, after

all, stand in necessary interconnection, for ‘it can seem impossibleto reconcile the fact that sentience belongs to our nature with thethought that spontaneity might permeate our perceptualexperience itself.’ 18 Yet this dilemma only arises in the first place,McDowell continues, if we commit ourselves in advance to a ‘baldnaturalism’ that simply equates the domain of nature as such withthe realm of law. And so, to relieve us of our intellectual burden,McDowell recommends that we instead adopt an Aristotelian

‘relaxed naturalism’, in which initiation into the space of reasonsis seen as a normal part of the maturation of adult human beings,wherein natural processes such as sensory perception becomeinfused with conceptual meaning. 19

Again, it is not my purpose here to challenge McDowell’sdiagnosis. 20 As in the case of Strawson’s reconstruction, however,I do want to point out how profoundly unKantian it is. Indeed, thereis a more than superficial affinity between the Strawsonian

conception of an autonomous realm of necessary conceptualconnections and McDowell’s picture of an autonomous space of reasons constituting the normative structure of our understanding.In particular, both see a ‘hard naturalism’ or ‘bald naturalism’committed to the hegemony of the modern mathematical-physicalsciences as the primary threat to a proper appreciation of the philo-sophical autonomy they wish to defend, and both recommend, in

17. Op. cit ., pp. 70–72.18. Op. cit ., p. 70, and compare p. 108.19. See op. cit. , pp. 76–84.20. See, however, my ‘Exorcising the Philosophical Tradition’, The Philosophical Review ,Vol. CV, No. 4, October 1996.


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response to this threat, a ‘soft naturalism’ or ‘relaxed naturalism’allowing us simply to embrace the autonomy in question as suigeneris . For both Strawson and McDowell, then, there is a

fundamental tension between the world-view of modernmathematical-physical science, on the one side, and the Kantianthemes they wish to reintroduce into contemporary philosophy, onthe other. And it is clear in both cases, I believe, that the problemin question arises directly out of the recent naturalistic attacks onthe autonomy of philosophy due, above all, to the work of Quine.Kant’s own philosophical situation is entirely different, however,and there is no such tension, for Kant, between his characteristic

conception of the philosophical enterprise and the world-view of modern mathematical-physical science. On the contrary, theprimary aim of Kant’s Transcendental Aesthetic and Analytic, aswe saw at the beginning, is precisely to explain how puremathematics and pure natural science are possible, so as therebyprecisely to underwrite, in particular, the new conception of naturearticulated in the modern mathematical-physical sciences.

The best way to see the importance of this point, in the present

context, is to glance briefly at the crucial step in Kant’s ownargument for establishing the necessary interdependence of understanding and sensibility. In this argument, the TranscendentalDeduction of the Categories, the necessary mediating role iscarried out by an activity or faculty Kant calls the ‘transcendentalsynthesis of the imagination’ or ‘the pure productive imagination’:

We thus have a pure faculty of imagination, as a fundamental facultyof the human soul, lying a priori at the basis of all our cognition. By

means of it we bring the manifold of intuition, on the one hand, inconnection with the condition of the necessary unity of pureapperception, on the other. The two extremes, namely sensibilityand understanding, must stand in necessary interconnection bymeans of this transcendental function of the imagination, becauseotherwise the former would indeed supply appearances, but noobjects of an empirical cognition, and thus no experience. (A124)

In §24 of the second edition version, entitled ‘On the application of

the categories to objects of the senses in general’, Kant explains thatthe transcendental synthesis of the imagination is an ‘action of theunderstanding on sensibility, and its first application (at the sametime the ground of all the rest) to objects of an intuition possible for


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us’ (B152). This transcendental synthesis, as belonging to theproductive rather than the reproductive imagination, is exerted onpure rather than empirical intuition (A118, B150–152), and Kant

proceeds to illustrate its action precisely by examples of geometrical construction (the drawing of a straight line, thedescribing of a circle), and also by the motion involved in suchgeometrical construction, regarded as ‘the external figurativerepresentation of time... whereby we attend to the succession of thisdetermination in [inner sense]’ (B154).

The pure imagination thus provides for both the application of geometry to objects of the senses and the application of what Kant

calls ‘the general doctrine of motion’ (B49). Kant himself insuresthat sensibility and understanding stand in necessaryinterconnection, in the first instance, by insuring that all empiricalobjects conform to the structure of Euclidean geometry, and also,if I am not mistaken, to the structure of what we now callNewtonian space–time. And we thereby guarantee, in preciselythis way, that synthetic a priori knowledge in fact serves as thecondition of possibility of all empirical knowledge. Far from

seeing the world-view of modern mathematical-physical scienceas any kind of threat to his philosophical transcendentalargumentation in the Aesthetic and Analytic of the Critique , Kantundertakes the key step in that argumentation precisely to securethe philosophical foundations of this world-view once and for all.

III

From these examples, it appears that we cannot so easily abstractKant’s characteristic conception of transcendental philosophyfrom the scientific context of his time. It appears, in particular, thatwe cannot so easily leave aside Kant’s preoccupation withsynthetic a priori mathematical-physical knowledge withoutdistorting his own philosophical impulse entirely beyondrecognition. So it is especially significant, in this context, that therehave also been attempts within the analytic tradition to reconstructand rehabilitate Kant’s philosophy of science as well, perhaps themost interesting of which, from the present point of view, is thatundertaken by Gerd Buchdahl. 21 For one of Buchdahl’s principal

21. G. Buchdahl, Metaphysics and the Philosophy of Science (Oxford: Blackwell, 1969).


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arguments is that we can preserve the centrality of mathematicaland physical scientific knowledge for Kantian philosophy, while,at the same time, loosening its apparent commitment to

specifically Euclidean-Newtonian science.Mathematical-physical science, for Buchdahl, is the product of the Kantian faculties of reason and judgement rather than thefaculties of understanding and sensibility. The faculties of reasonand judgement, guided by regulative principles of unity, simplicity,and so on, aim to construct theories, conceptualizations, and lawsthat inject systematic scientific order into the domain of spatio-temporally ordered particulars which is the immediate product of

the constitutive activities of the understanding and sensibility. The‘nature’ produced by the constitutive activities of the under-standing and sensibility, ‘a mere concatenated plurality’ of spatio-temporal particulars, is thereby transformed into an ‘order of nature’ governed by systematic scientific laws. 22 Moreover, thescientific systems produced by the faculties of reason and

judgement, have a ‘constructive’, or ‘postulational’ character, inthat they involve concepts and principles (such as basic principles

of geometry or mechanics) that are not straightforward inductivegeneralizations. Such initial conceptual stipulations insteadresemble what more recent philosophers of science have called‘implicit definitions’, the ‘functional a priori’, or, in theterminology of Thomas Kuhn, subject-defining ‘paradigms’. 23Like Kuhnian paradigms, however, such postulational stipulationsneed in no way be fixed for all time. On the contrary, beingproducts of our decision and choice, we are free to revise andtransform them as the need arises. So there is not only room, onBuchdahl’s reading, for a non-Newtonian physics, but even for anon-Euclidean geometry.

What makes this loosening of the Kantian commitment tospecifically Euclidean-Newtonian science possible is a strict andsharp separation between the ‘nature’ produced by the constitutiveactivities of the understanding and sensibility and the ‘order of nature’ constructed by the merely regulative activities of reasonand judgement. Buchdahl requires, accordingly, that ‘thisseparation between science (as a body of laws) and the world of

22. Op. cit ., pp. 480–481.23. Op. cit ., pp. 33, 510–511, 676.


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commonsense objects be made complete.’ 24 For the ‘nature’produced by the constitutive activities of the understanding andsensibility is constituted entirely independently of all

mathematical-physical theorizing, and thus comprises ‘thestraightforward things of commonsense’ bereft of all ‘scientifico-theoretical components’. 25 Kant’s Transcendental Deduction of the Categories, in particular, is aimed only at the spatio-temporalordering of commonsense objects and events, and it serves merelyto supply a ‘spatial and temporal clamp’ or ‘conceptual clamp’making this previously indeterminate ordering both determinateand objective. 26 The Transcendental Deduction in particular, and

the Transcendental Aesthetic and Analytic more generally, arethus in no way concerned with any particular mathematical-physical scientific theory; indeed, if Buchdahl is correct, they arenot concerned with scientific theorizing at all.

We have seen, however, that such a reading of theTranscendental Aesthetic and Analytic is untenable. For not onlyis Kant’s own argumentation explicitly framed by the questions‘How is pure mathematics possible?’ and ‘How is pure natural

science possible?’ respectively, but the Transcendental Deduction,in particular, effects a ‘conceptual clamp’ uniting understandingand sensibility precisely through the pure imagination, and thus,in turn, through a transcendental synthesis exemplified bygeometrical construction, on the one hand, and the generaldoctrine of motion, on the other. In this way, the transcendentalsynthesis expressing the ‘first application’ of the understanding tosensibility injects the principles of (Euclidean) geometry and

(Newtonian) mechanics into the sensible appearances, andtherefore makes possible their determinate spatio-temporalordering precisely in so far as they are thereby subject tomathematical-physical scientific laws. Indeed, it is otherwiseentirely obscure what the notion of ‘spatio-temporal clamp’ or‘conceptual clamp’ could possibly mean here. Buchdahl’sseparation between the constitutive domain of the understandingand sensibility and the constructive activity of scientific theorizing

leaves us with an insecure grasp on the characteristically Kantian24. Op. cit ., p. 659.25. Op. cit ., pp. 638–639, note 4.26. Op. cit ., pp. 621, 635.


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conception of constitutive, synthetic a priori knowledge, and aninsecure appreciation, therefore, of what Kant himself takes to bethe peculiarly transcendental function of philosophy.

IV

Buchdahl’s interpretation of the constructive activity of scientifictheorizing, by contrast, is quite insightful and suggestive, for it infact indicates a way in which the Kantian conception of synthetica priori knowledge can be illuminatingly generalized beyond itsEuclidean-Newtonian context. Indeed, such a generalization of theKantian a priori, whereby it loses its rigidly fixed character butretains its essential constitutive function with respect to empiricalknowledge, was actually common coin within early twentiethcentury scientific philosophy.

Thus Henri Poincaré, for example, developed a radically newinterpretation of the status of geometry, based on his ownfundamental work on non-Euclidean spaces, according to whichgeometry is neither ( pace Kant) a synthetic a priori product of ourpure intuition nor ( pace Gauss and Helmholtz) a straightforwardempirical description of what we can experience in nature.Establishing one or another system of geometry rather requires afree choice, a convention of our own in order to bridge theirreducible gulf between our crude and approximate sensoryexperience and our precise mathematical descriptions of nature.And Hans Reichenbach, to take a second example, accordinglydistinguished two meanings of the Kantian a priori: necessary andunrevisable, fixed for all time, on the one hand, and ‘constitutiveof the concept of the object of knowledge’, on the other. 27 Heargued, on this basis, that the great lesson of the theory of relativityis that the former meaning must be dropped while the latter mustbe retained. Relativity theory, that is, involves a priori constitutiveprinciples as necessary presupposition of its properly empiricalclaims, just as much as did Newtonian physics, but these principleshave essentially changed in the transition from the latter theory tothe former. So what we end up with, following out both of thesesuggestions, is a relativized and dynamical conception of a priorimathematical-physical principles, which change and develop

27. H. Reichenbach, Relativitätstheorie und Erkenntnis Apriori (Berlin: Springer, 1920).


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along with the development of the mathematical and physicalsciences themselves, but which nevertheless retain the character-istically Kantian constitutive function of making the empirical

natural knowledge thereby structured and framed by suchprinciples first possible.Within more recent philosophy of science, as Buchdahl himself

intimates, we find very clear descendants of this conception: mostnotably, in Rudolf Carnap’s distinction between changes of language or linguistic framework, on the one side, and revisionsof properly empirical statements formulated within a givenlinguistic framework, on the other, and in Thomas Kuhn’s closely

related distinction between revolutionary changes of scientificparadigm and the problem-solving activities of normal science.Indeed, Kuhn explicitly acknowledged the intimate kinshipbetween his conception and that of the relativized or conventionala priori arising in the work of such logical empiricist philosophersas Reichenbach and Carnap, and thus that between his conceptionand ‘Kant’s a priori when the latter is taken in [a] relativizedsense’. 28

Where we cannot follow Buchdahl, I believe, is in his attempt,in addition, to defend a non-relativized, non-dynamical version of the Kantian constitutive a priori, produced, supposedly, by thefaculties of understanding and sensibility acting independently of all constructive mathematical and physical theorizing, andconfined, accordingly, to the spatio-temporal structure of commonsense as opposed to scientific knowledge. This attempt notonly fundamentally distorts the Kantian texts, as I argued above,

but it also fundamentally distorts our own relation to the Kantianenterprise. Kant lived at a time when the most basicpresuppositions of contemporary science, Euclidean geometry andNewtonian mechanics, could be very plausibly held to beabsolutely fixed conditions of the possibility of all experience ingeneral. For Euclidean geometry and Newtonian mechanics, inKant’s time, simply had no conceivable alternatives. But now thatwe have lost this position of innocence, I believe, we should no

longer persist, nonetheless, in the ambition to articulate timelessphilosophical truths delimiting the spatio-temporal structure of all

28. T. Kuhn, ‘Afterwords’, in World Changes , ed. P. Horwich (Cambridge: MIT, 1993),pp. 313–315, 331–332.


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human experience in general. We should recognize, rather, that theKantian conception of the peculiarly transcendental function of philosophy must itself be relativized and generalized.

Thus our modern conception of a dynamical, yet stillconstitutive a priori is the product of our own time and our ownintellectual situation. It does not make sense in the context of Kant’s eighteenth century situation. Although it is true, asBuchdahl rightly emphasizes, that Kant’s conception of theregulative use of reason is quite modern in its open-endedness andfluidity, Kant himself explicitly distinguishes the regulativeprinciples governing this indefinite progress of reason (simplicity,

unity, and so on) from the constitutive principles, produced by theinteraction of understanding and sensibility, that articulate thefixed background spatio-temporal structure of all possibleempirical science. There can be very little doubt, as I haverepeatedly urged above, that this fixed background structureessentially includes, for Kant, the principles of Euclideangeometry and Newtonian mechanics. And there is also very littledoubt, as I have just suggested, that this is by far the most plausibleand insightful philosophical reading of the situation in the contextof eighteenth century science.

Throughout the nineteenth century, by contrast, there wererepeated attempts by mathematicians, natural scientists, andphilosophers to break free from such constraints—both from theconstraints of Euclidean geometry and from the correspondingconstraints of Kantian epistemology. For the leading thinkers of

this period struggled to articulate new mathematical conceptionsthat would generalize and transform traditional Euclideangeometry, and also new philosophical conceptions that wouldgeneralize and transform the doctrines of Kant. Thesedevelopments culminated, in the early years of the twentiethcentury, in Einstein’s theory of relativity, wherein the radicallynew geometrical ideas developed in the preceding century areworked up into a new mathematical-physical framework for space,

time, and motion capable of competing with, and eventuallyreplacing, the Euclidean-Newtonian framework. And thecorresponding dynamical, explicitly relativized conception of apriori constitutive principles developed by such philosophers as


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the logical empiricists was then articulated in self-consciousresponse to precisely these new scientific developments.

What we see here, then, is that the enterprise Kant called

transcendental philosophy—the project of articulating and philo-sophically contextualizing the most basic constitutive principlesdefining the fundamental spatio-temporal framework of empiricalnatural science—is just as dynamical and historically situated asare the mathematical-physical constitutive principles which are itsobject. Indeed, the relationship between transcendental philosophyin this sense and the mathematical-physical principles whosepossibility it examines and articulates is best seen as thoroughly

dialectical. Not only do new developments in mathematical-physical constitutive principles lead to new developments in thisphilosophical enterprise (as the Newtonian synthesis led to Kant,say, or Einstein to the philosophy of logical empiricism), but theinfluence, and interaction, flows in the other direction as well.Thus, the Newtonian synthesis would itself not have been possiblewithout the earlier attempts to articulate and philosophicallycontextualize the spatio-temporal framework of the new

mathematical science by such thinkers as Descartes and Leibniz,without whom, we might add, the transcendental philosophy of Kant would also not have been possible. Similarly, Einstein’sdevelopment of the theory of relativity was deeply influenced by,albeit partly by way of reaction against, the earlier conventionalistphilosophy of geometry articulated by Poincaré, which also, of course, greatly influenced the subsequent philosophy of logicalempiricism. And, finally, the nineteenth century developments in

mathematics, natural science, and philosophy that eventuated inthe theory of relativity (including the work of Poincaré) werethemselves often explicitly motivated by attempts either togeneralize or radically transform the philosophy of Kant.

Yet this emphatically does not mean, as contemporaryphilosophical naturalism would have it, that philosophy simplybecomes absorbed into empirical natural science as one morecomponent of an holistically conceived ‘web of belief’. On the

contrary, just as our most sophisticated contemporaryhistoriography of science demands that we maintain a distinction,in Kuhn’s terminology, between change of paradigm and normalscience (and thus, in Kantian terminology, between constitutive


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principles and properly empirical claims framed against thebackground of such principles), so our present picture of thepeculiarly transcendental function of philosophy demands that we

maintain a further and parallel distinction between philosophicalchanges and properly scientific ones. If revolutionary science,wherein we change the very paradigm or framework within whichthe problem-solving activities of normal science proceed, takesplace at one level removed, as it were, from these problem-solvingactivities themselves, then transcendental philosophy in thepresent sense, wherein we articulate and philosophicallycontextualize the paradigms or constitutive frameworks developedin revolutionary science (as Kant articulated and contextualizedthe Newtonian framework, say, or the logical empiricists did thesame for the Einsteinian), takes place rather at two levels removed.In this way, despite being just as dynamical and historicallysituated as are the scientific constitutive principles which are itsobject, transcendental philosophy in this sense retains a distinctiveand absolutely essential role in the ongoing dialectic of knowledge. Perhaps that is distinction enough.

FRIEDMAN & BIRD- Kantian Themes in Contemporary Philosophy

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