neo-kantian philosophies of science- cassirer, kuhn, and friedman

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NEO-KANTIAN PHILOSOPHIES OF SCIENCE:CASSIRER, KUHN, AND FRIEDMAN1

ANDREW CHIGNELL

I. INTRODUCTION: KUHN AND NEO-KANTIANISM

In some recent writings, as well as in the article published here, Michael

Friedman offers a fascinating account of how Thomas Kuhns groundbreaking

work in the history and philosophy of science is related toand even explicitly

indebted toan important strand of Neo-Kantianism. Friedman shows that

Kuhns talk of shifts between paradigms, in particular, is influenced by theNeo-Kantian conception of the exact sciences as evolving by way of a series of

massive structural transitions which do not aim at convergence to a final truth

about a mind-independent reality (p. 242).2 Kuhn takes a step beyond the Neo-

Kantians, however, in giving up not just convergence towards things-in-

themselves but also any sort of convergence at all.

According to Friedman, this final step of Kuhns is in fact a misstepan

unfortunate result of the fact that he followed Alexandre Koyr and Emile Mey-

erson in assuming that any convergence in mathematical physics would have to be

substantial. Substantial convergence, roughly speaking, involves a series oftheoretical structures having the same physical referents but accounting for them

(descriptively and predictively) in an increasingly adequate way. And this, as Kuhn

himself points out, is not the way the history of the exact sciences has actually

gone. Instead, the physical referents of, say, the Einsteinian theory are essentially

and substantially different from the physical referents of the Newtonian theory.

1 I am grateful to Michael Friedman, Kristopher McDaniel, and other participants in the Classical

Neo-Kantianism conference at Cornell for helpful discussion of these ideas.

2 Page numbers in this article refer to Michael Friedman, Ernst Cassirer and Thomas Kuhn: TheNeo-Kantian Tradition in History and Philosophy of Science, Philosophical Forum 39 (2008):

23952.

2008 The Philosophical Forum, Inc.

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Since this rules out substantial convergence, and since substantial convergence is

by hypothesis the only kind of convergence on offer, we are left with no good story

about how the shift can be seen as both revolutionary and rational from the pointof view of the earlier paradigm.3 Kuhns misstep thus sets the stage for the radically

relativistic appropriations of his work by subsequent historians and sociologists of

science, appropriations that Friedman wants to resist.

In order to avoid Kuhns misstep, Friedman recommends that we go back

before Kuhn, Koyr, and Meyerson to Ernst Cassirer, a leading member of the

Marburg school of Neo-Kantianism and one of the intellectual forebears of the

present discussion. Cassirers Das Erkenntnisproblem4 and Substanzbegriff und

Funktionsbegriff5 were written just as the Einsteinian revolution was taking place

(the anno mirabilis was 1905, though general relativity would have to wait untilthe next decade). Along with his followers Leon Brunschvicg and Anneliese

Maier, Cassirer proposed to deal with these post-Kantian developments in math

and physics by thinking of convergence not as substantial but rather as

functionalthat is, as the convergence of abstract mathematical structures,

regardless of their physical referents, to a final or limit theory, such that all

previous theories in the sequence are approximate special cases of this final

theory (p. 242). This allows us to abandon the quixotic quest for correspondence

to the things-in-themselves and yet retain the ideal of convergence to reality

instead of accepting a radical incommensurability thesis. That in turn is because,according to the Marburgers and their followers, reality (what Kant would call

empirical reality) is just the pure ideal limit theory itself or, equivalently, the

series [of converging structures] itself, taken as a whole (p. 3).6 This novel view

of convergence thus seeks to salvage claims about the rationality of scientific

3 Kuhn is well aware of this last point, of course, and tries in The Structure of Scientific Revolutions,

2nd ed. (Chicago, IL: U of Chicago P, 1970; original edition published in 1962) and elsewhere to

avoid the extreme consequences which others have celebrated. In his Dynamics of Reason (Stanford:

CSLI Publications, 2001), Friedman shows that Kuhns attempt is a failure and that if we stick withthe substantialist picture that Kuhn inherited from Koyr and Meyerson, we do indeed end up with

a radical incommensurability thesis according to which (1) all knowledge is local or relative to a

particular paradigm, and (2) what we call scientific progress is a series of revolutions that simply

cannot be seen as prospectively rationalthat is, rational from the point of view of the antecedent

theories.4 Ernst Cassirer, Das Erkenntnisproblem in der Philosophie und Wissenschaft der neueren Zeit, 2 vols.

(Berlin: Bruno Cassirer, 190607).5 Ernst Cassirer, Substanzbegriff und Funktionsbegriff (Berlin: Bruno Cassirer, 1910).6 The reason that the limit theory is equivalentto the entire series is that the limit theory (which always

remains a regulative ideal for Friedman and Cassirer) will include or entail all of the previous

structures as approximate special cases. A prime example is the way in which Euclidean geometryis included in or entailed by non-Euclidean geometry as a special case that is restricted to certain

parameters.

ANDREW CHIGNELL

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revolutions by viewing earlier theories as special cases of later theories and by

seeing the approximation of reality as the ultimate goal.

Friedman does not recommend a full-scale return to the Neo-Kantian picture;however, he follows Kuhn and, before him, Carnap, Reichenbach, and other logical

empiricists in holding that the Newtonian and Einsteinian theories are incommen-

surable in some important sense. This is because even after the mathematics

required for Einsteins theory was developed, it still remained fundamentally

unclear what it could mean actually to apply such a geometry to our sensible ex-

perience of nature in a real physical theory (p. 249). So whereas Cassirer assumed

that the Einsteinian revolution could be accommodated by the Neo-Kantian picture

without difficulty by talking about functional convergence at the abstract math-

ematical level, Friedman thinks that additional philosophical work is required toshow how the abstract structures of the new paradigm apply to some physical

referent or other and thus receive a kind of empirical meaning or content (what Kant

would call objective reality). If it is successful, this philosophical work results in

the expansion or stimulation of new empirical possibilities. If it evolves

naturally out of the old paradigm, then the shift that it enables can be considered

rational, even though the paradigms in question are substantially incommensurable.

Friedmans discussion here is in many ways a rich prcis of the broader research

program that animates much of his recent work. Clearly I do not have space here

to discuss all of its important aspects and will instead simply raise some criticalquestions about three main issues: (1) about the sense in which the shifts between

paradigms involve a relativizing or moving of the Kantian categories or forms

of intuition and an historicizing of transcendental philosophy itself; (2) about

how coordinating principles actually acquire constitutive a priori status relative to

a paradigm; and (3) about whether the kind of transcendental philosophy Friedman

recommends can really generate new empirical possibilities in any Kantian sense

and whether it is even something that most philosophers can hope to practice.

II. ASPECTS OF FUNCTIONAL CONVERGENCE

II.1. Moving Categories

Friedman follows Kuhn and Reichenbach in holding that what a Kantian should

do in order to accommodate the fact of scientific revolutions is to relativize the

constitutive a priori to specific theoretical structuresthat is, to think of the

categories as moveable, to use Kuhns own metaphor, rather than as fixed

forever in the mode in which Kant himself deduced them.

I worry, however, about whether this moveable metaphor is not more mis-leading than it is helpful. It presumably does not mean merely that in different

theories with different ontological commitments, the very general categories will

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apply to different things or even different kinds of things. For even Kant would

accept that. But that the suggests that the claim about moveability is that the

categories themselves actually change from paradigm to paradigm. Withoutattempting to discuss the relevant math and science, I want to hazard the sugges-

tion that, on the contrary, even in the new paradigm we can and often must still

employ the general categories of possibility, actuality, necessity, unity, plurality,

totality, reality, negation, and limitation. It is not as clear what to say about Kants

category of inherence and subsistence, though I would note in this connection

that Friedmans own description of Einsteins theory makes reference to bodies

and their properties (p. 248). Further, the philosophical project recommended to us

in Friedmans workthat of discerning how abstract mathematical structures can

apply to physical referents in empirical natureseems to rest on the assumptionthat nature has an articulate structure and can be conceived in terms of subsisting

phenomena (fields or masses or whatever) with various inhering properties.

Likewise, the categories of causality and community are surely applicable in the

new paradigm insofar as we continue to speak of laws and forces. Indeed, it may

even be that some of the schemata and pure principles that emerge from Kants

categories also survive the shift to the Einsteinian paradigmthe schema of

reality, for instance, which is simply that of being in time (A143/B182),7 or the

principle of the Second Analogy according to which All alterations occur in

accordance with the law of the connection of cause and effect (B232),8

or theprinciple of the Anticipations of Perception according to which all spatiotemporal

intuitions have an intensive magnitude (A165/B207).

This may be a minor point, since Friedman is clearly right to say that there is

much relativizing of the framework that goes on in shifting between paradigms.

But it does seem worth noting that this typically occurs quite a bit further down in

the Kantian framework, so to speak, than at the level of the categories themselves.

The constitutive a priori principles that are the main focus in this discussion,

tell us more about the specific meaning of the categories relative to a given

paradigmabout what they apply to in that theoretical context. And while thoselower-level principles are indeed moveable, the categories themselves seem to

stay put across shifts.

7 Immanuel Kant, Kants gesammlte Schriften, ed. Royal Prussian (now Berlin-Brandenburg) Academy

of Sciences (Berlin: Georg Reimer, now Walter de Gruyter, 1900ongoing), 29 vols. (vol. 26 yet to

be published). Kritik der reinen Vernunft (1781/87) cited by A/B pagination; other Akademie

volumes by volume number: page number. English translations are done in consultation with the

Cambridge Edition of the Works of Immanuel Kant, ed. Paul Guyer and Allen Wood (New York:Cambridge, 1992present).

8 Recall that Einstein himself always remained a complete determinist.

ANDREW CHIGNELL

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II.2. Shifting Forms of Intuition

A related worry has to do with whether and how, on this revised Neo-Kantian

picture, the forms of intuition are also supposed to be relativized in some sense.Friedman does not mention intuition much in this article, except to criticize

Cassirer and other Marburgers for ignoring the crucial role it plays in Kants

theory (p. 247). So that leaves it unclear what, if any, the role of intuition in

Friedmans revised Neo-Kantian picture is supposed to be. Obviously in a

Riemannian paradigm, the axioms of space will be different than they were in a

Euclidean one.9 But how can we make sense of this if we want to remain tran-

scendental idealists?

One rather extreme thing to say is that the minds way of apprehending space

actually changes relative to the theoretical paradigm in which we are working.This would amount to a radical and quite implausible version of the Kuhn-inspired

theme that all perception is theory-laden.10 A less extreme thing to say, and one that

I want to recommend here, is that the real structure of space-time is determined

by empirical realitythat is, by the final theory toward which we are, by

hypothesis, functionally converging. If we could somehow know now what that

theory is, then we would be able to deduce synthetic judgments about the way our

intuitional experience is, will, and must be in a way that would make Kant very

happy. As things are, the transcendental idealist can still hold (with Kant) that all

of our intuitional experience is necessarily structured in accordance with theaxioms of our best theory of space-time. It is just that now we think of that best

theory as a regulative ideal instead of assuming that Euclid and Newton have

already discovered it.

II.3. Historicized Philosophy

In addition to advocating this sort of relativizing of the constitutive a priori,

Friedman speaks of historicizing transcendental philosophy itself and even

suggests that the former move entails the latter as a sort of consequence (p. 251).The idea is that when we relativize the constitutive a priori, the very notion of

what transcendental philosophy is also has to be adjusted in some way. But this too

9 It is less clear that the axioms of time would have to change in the shift from a Newtonian to an

Einsteinian paradigm. The only axiom of time that Kant cites in the Aesthetic is that it has only one

dimension: different times are not simultaneous, but successive (A31/B47). But this would be true

even if times are relativized to inertial frames, since within a frame there would still be no two

different times that are simultaneous, nor would it make sense to claim that there are two non-

identical but still simultaneous times across inertial frames. Thanks to Kris McDaniel for discussionhere.

10 See Kuhn (1962): ch. 10.


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strikes me as dubious: Why cant transcendental philosophy be statically con-

ceived as the project of seeking the necessary presuppositions of the empirical

application ofwhatever our best theoretical concepts are, even if the latter occa-sionally change? When the theory changes, of course, so do the presuppositions

which transcendental philosophers deduce. Or, better, the theories and the presup-

positions change togetherwe have seen that the revolution is not complete until

the presuppositions of the new theory have been worked out and their constituent

concepts have been given empirical content. But it seems odd to say that relativ-

izing the constitutive a priori involves historicizing philosophy itself. Wouldnt it

be better to say that the results of philosophy are historicized but that the general

goals and methods of philosophers, abstractly conceived, remain constant across

the shifts?

III. WHAT MAKES IT CONSTITUTIVE A PRIORI?

A second set of worries about Friedmans picture has to do with how he sees a

given principle achieving the status of constitutive a priori relative to a paradigm.

The worries arise most clearly in connection with the following passage:

[W]hereas Euclidean geometry and the Newtonian laws of motion were indeed necessary presup-

positions for the empirical meaning and application of the Newtonian theory of universal gravita-

tion (and they were therefore constitutively a priori in this context), the radically new mathematicaland physical framework consisting of the Riemannian theory of manifolds and the principle of

equivalence defines an analogous system of necessary presuppositions in general relativity. More-

over, what makes this latter framework constitutively a priori in this new context is precisely the

circumstance that Einstein was only able to arrive at it in the first place by self-consciously situating

himself within the earlier tradition of scientific philosophy represented by Helmholtz, Mach, and

Poincarjust as this tradition, in turn, had earlier self-consciously situated itself against the

background of the original version of transcendental philosophy first articulated by Kant. (p. 251,

emphasis added)

There are many things to agree with about this proposal. It is certainly true thatworking within the tradition of Poincar, Mach, and Helmholtz is what helped

Einstein to discover the principle of equivalence. It also very likely ensured that

his proposal would be taken seriously and be worked on by others, since scientists

are usually only interested in proposals that have a natural connection to existing

research programs and yet promise to solve problems that the latter dont. Finally,

perhaps this historical fact about how Einstein came up with the principle of

equivalence does help make his theory seem like a natural and rational

successor to preceding theories. Still, it is hard to see how the way in which

Einstein self-consciously situated himself could be what made the principle ofequivalence constitutively a priori in the new paradigm. The system of necessary

presuppositions of a theory is presumably something like the set of logical or

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quasi-logical conditions which we must (perhaps implicitly) accept if we accept

the theory itself. But then the fact that a particular principle is one of these

presuppositions and thus constitutive a priori relative to the theory in questionappears to be a hard fact of transcendental logic. And, again, it is hard to see how

such facts can be made to obtain simply in virtue of the way that someone

discovers them.

IV. EXPANDING POSSIBILITIES

A final set of objections has to do with Friedmans claim that the generation of

coordinating principles such as the principle of equivalence expands our empiri-

cal possibilities by showing that the abstract concepts in the mathematical struc-ture mean somethingthat is, are applicable to phenomenal nature.11 Friedman

explicitly ties his discussion here to Kants notion of real possibility and says in

his bookDynamics of Reason that it is precisely because we retain a counterpart

to this notion that the Kantian terminology of constitutive principles is still

appropriate.12 For Kant himself, however, there are a number of different notions

of real possibility that have different extensions, and it is worth discussing pre-

cisely which one is being invoked here.13

The first kind of real possibility is defined by the powers and natures of the

things-in-themselves; Kant calls it absolute possibility (absolute Mglichkeit)and assumes that it is something about which we know next to nothing (A232/

B285).14 This is clearly not the kind of real possibility which is relevant to our

discussion here. There is also what Kant calls empirical real possibility. And,

though he does not make this as clear as he should, there are actually two different

species of this kind of real possibility at work in the critical philosophy. The first

is derivable from the definition of empirical necessity in the Postulatesnamely,

that which is connected with the actual in accordance with the universal condi-

tions of experience (A218/B266). By connection here Kant means, at the very

11 So, for example, although general relativity was both logically and empirically impossible from the

point of view of Newtonian physics, the mathematical developments of the 19th century made it

logically possible, and the developments in physical scientific observation provided the anomalies

which made a shift seem necessary. The role of philosophy was then show how the abstract

theoretical structure of Einsteins theory could be applied to empirical realitythereby providing

meaning (or what Kant would call objective reality) to its constituent concepts. Success at this

task, for Friedman, leads to an expansion of the empirical possibilities.12 Friedman (2001): 84n.13 For a more detailed discussion of the various types of modality in Kant, see Andrew Chignell and

Nicholas Stang, Postulate des empirischen Denkens, Kant-Lexikon, ed. G. Mohr, J. Stolzenberg &M. Willaschek (Berlin: Walter de Gruyter, forthcoming).

14 Cf. lecture notes at Akademie 28: 418, 498, 55658, 633.


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least, causal connection. But since the Analogies prove that everything empiri-

cally actual is causally connected with some antecedent cause, it turns out that the

empirically actual and the empirically necessary (and ergo the empirically pos-sible) are coextensive for Kant (cf. his comment that no addition to the actual is

possible at A231/B284). It should be clear that this, too, is not the sense of

empirical possibility that Friedman has in mind, since he holds (following

Kuhn) that there are many or even infinite empirical possibilities relative to a

paradigm and that the job of normal science is to discover which of those possi-

bilities in fact obtain.15

The second species of empirical real possibility is defined by Kant in the

postulate of possibility as that which agrees (bereinkommt) with the formal

conditions of experience (according to intuition and concept). This is clearly onthe right track, since it allows for non-actual possibilities, provided we interpret

formal conditions in a way which abstracts from fine-grained, particular empiri-

cal laws and the actual set of initial conditions. But there are still two ways to

interpret this notion in the context of our present discussion, and I am not sure

which way Friedman is going. The first interpretation says that what is empirically

really possible is something like that which is consistent with the constitutive a

priori principles of our current theory. On this interpretation, the empirically

possible will vary from theory to theory, and so a shift from one theory to another

really does open up, stimulate, or generate new empirical possibilities.A second, weaker interpretation says that the empirically really possible is that

which is consistent with the constitutive a priori principles of the ideal, limit theory

toward which exact science is functionally converging. This interpretation allows

us to say that, just as noumenal reality defines what is absolutely possible,

empirical reality (conceived as the ideal limit theory, or the series of structures

converging on that theory) defines what is empirically possible. But then the

expansion of our empirical possibilities that results from deducing the consti-

tutive a priori principles of a new paradigm is merely an epistemological expan-

sion rather than any sort of metaphysical one. For what is truly empirically reallypossible does not change: It is always defined by the constitutive a priori prin-

ciples of the ideal limit theory. But our beliefs about what is empirically really

possible does changehopefully in the direction of that ideal toward which we

are converging.

I find Friedmans own discussion somewhat ambiguous between these two

interpretations: He says that what scientific philosophy does expand our

possibilities,16 articulate and stimulate new possibilities,17 generate principles

15 Friedman (2001): 43.16 Ibid: 23, 46.17 Ibid: 24.

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which lead to entirely new empirical possibilit[ies],18 or even make [a] theory

physically or empirically possible in the first place.19 He also says that in the

Newtonian context, Einsteins theory is, in Kants terminology, [. . .] neitherlogically nor really possible (p. 249), which I take to mean that the objects or

referents of the theory are not really possible. These phrases evoke the first

interpretation.

But elsewhere it sounds as though we are supposed to conceive of the relevant

activity as more like discovery than creation: Philosophy is involved in clarifying

and articulating the new space of intellectual possibilities,20 and Einsteins great

innovation in generating the principle of equivalence was a conceptual onethe

recognition of a new item, as it were, in the space of intellectual possibilities. 21 I

want to suggest, in any case, that the second interpretation is friendlier to theoverall Neo-Kantian project in which Friedman is engaged. The first interpreta-

tion, by contrastthe one according to which our deduction of new coordinating

principles actually makes some things really possiblecomports better with the

kind of radical post-Kuhnian picture which Friedman wants to resist.

V. PROSPECTS FOR TRANSCENDENTAL PHILOSOPHY

Let me conclude by making a final point about the claim that this projectthe

project of finding and articulating the coordinating principles which in turn definethe empirical possibilities of the theory and also give real content to its abstract

mathematical structuresshould be thought of as defining the peculiar role of

transcendental philosophy.22 A frequent target of Friedmans work on these issues

is W. V. O. Quine, in part because Quine wanted to cede much if not all of the

territory of philosophy to the natural sciences: ontology to the physicists; episte-

mology, mind, and language to the empirical psychologists and cognitive scien-

tists; and so forth. In Dynamics of Reason, Friedman likewise takes issue with

Helmholtzs suggestion that philosophy should ultimately give way to some kind

of empirical physico-psychology.23

But although the peculiar role that Friedman reserves for his brand of tran-

scendental philosophy might in fact be qualitatively different from the normal

practices of scientific investigation, it is noteworthy that all of the 20th-century

figures that he credits with having done the sort of thing he recommends are what

18 Ibid: 9.19 Ibid: 11.20 Ibid: 46.

21 Ibid: 23, emphasis mine.22 Ibid: 24.23 Ibid: 7.


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we would think of as scientists and not, or not primarily, as philosophers. These

are the sort of people who tie together the relevant innovations in mathematics

and physics and thereby effect the necessary expansion in our physical orempirical possibilities (p. 250). Helmholtz, Poincar, Mach, and Einstein are not

extensively studied in your average philosophy department, and of these four only

Einstein made it into the Library of Living Philosophers. So my worry is that

Friedmans recommendations about what kind of philosophy remains viable will

end up saving philosophy from the sciences but still hand it over to the scientists.

In other words, the only people with the expertise that is required to do the kind

of philosophy that Friedman is recommending will be, like Einstein, highly

trained scientists in their own right. And while this conclusion is not quite as

pessimistic as Quines or Helmholtzs, it is still one that many would-be Kantianphilosophers will find rather gloomy.

Sage School of Philosophy, Cornell University

ANDREW CHIGNELL

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neo-kantian philosophies of science- cassirer, kuhn, and friedman

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