## 1. Natorp and Marburg neo-Kantianism



Neo-Kantianism, it is often said, was the dominant current of late
nineteenth-century German academic philosophy. While true, this
statement is uninformative, since the label conveys no clear doctrinal
content. Given the widespread perception that philosophy had become
discredited by the untenable claims of the German Idealists, the
various neo-Kantian schools shared a conviction that Kant--on
some interpretation of his sobriety--could give philosophy a
respectable and genuine task again, now that it had awakened from its
long post-Hegelian hangover (cf. Natorp 1918a: 4-6; Dussort
1963; Schnadelbach 1983a, 1983b; Kohnke 1986; Philonenko 1989; Sluga 1976: 28). The
label therefore does not necessarily signify a revival of Kant's
doctrines (much less of Kant-scholarship for its own
 sake[6]
 ), but rather, as Natorp himself puts it, philosophizing in the
spirit of Kant (Natorp 1918a: 7). But what does that mean? For the
Marburg School, Kant's great idea, "the central notion
with respect to which one must relate, understand, and evaluate
everything else in Kant" is the *transcendental method*
(Natorp 1912c: 194; cf. Cassirer 1925: 288). This method constitutes
"the unshakeable guideline of our whole philosophizing"
(Natorp 1912c: 196). Why? Because the transcendental method anchors
philosophy in facts (eminently the fact of mathematical physics),
*of which* philosophy is to establish the conditions of
possibility or justification (*Rechtsgrund*) (Natorp 1912c:
197; 196). By limiting itself to this task of justification,
philosophical reason keeps itself from ascending into the aether of
speculation. At the same time, by discovering the source of scientific
objectivity (and thus of rational objectivity generally), i.e., by
"clearly exhibiting the law [of objectivity] in its
purity", philosophy "secures science [and rational
activity generally] in its autonomy and preserves it from alien
distraction" (Natorp 1912c: 197-198). Transcendental
philosophy in the Kantian spirit, then, is doubly
"critical", checking itself against metaphysical excesses,
on the one hand, but also rigorously formulating the ideal grounds of
the sciences, on the other (Natorp 1912c: 198; cf. Poma 1997, ch. 3,
4). At the same time, the Marburg School finds in the critical
philosophy an idealistic bulwark against the empiricism epitomized by
Mill.



Moreover, the Marburgers endorsed Kant's view that philosophy
should adopt an approach to the other domains of human
culture--morality, art, and religion--that was
"critical" in just the transcendental sense described
above. This approach, then, takes the critique of science as the
paradigm of philosophy's relation to culture in general. Just as
the critical theory of science begins from the concrete theories
developed by the special sciences, so philosophy in general should
begin from the achievements of culture (e.g., works of art, moral
action or institutions), and investigate the basis of their claims.
This is one reason Cohen and Natorp call their critical philosophy
"idealism", because its task vis-a-vis culture is
to lay out the system of rational principles that make possible the
"facts" of science, morality, and art. At the same time,
their idealism aims at making explicit the "ideas" that
guide, or ought to guide, the continuous development of culture.
Finally, the Marburgers' very theory of transcendental
principles is itself "idealistic" in the radical sense
that all objects of experience are held to be the products solely of
the activity of thinking. Nevertheless, Marburg theory denies
philosophy any "speculative" task of seeing or knowing
things that are beyond experience, of constructing systems of ideas
that are not immanent in the facts of human knowledge, action, or
production. Like Cassirer, Natorp makes this view of philosophy in the
Kantian spirit the basis of his own philosophy of science and of his
historical interpretations.



One main reason why neo-Kantians of all stripes see the essence of
philosophy in critique is that it guarantees philosophy's
autonomy (cf. Natorp 1887: 266-269, 285, *et passim*). Of
all rational activities, philosophy alone has the task of discovering
the conditions and regulative ideals that make such activities at all
possible. While the problem of philosophy's identity as a
discipline of course goes back to Plato, we are faced, in the
nineteenth-century German context, with the particular problem of
philosophy's relation to the positive sciences, which had
completely repudiated and replaced the knowledge-claims of the
speculative systems of German Idealism. For the Marburgers, the issue
of philosophy's disciplinary integrity becomes intertwined with
the question of the autonomy of reason itself. Cohen and Natorp faced
a difficult task. Having turned their backs on speculative philosophy,
they could not define reason's autonomy by falling back upon the
discredited *Geist* of German
 Idealism.[7]
 But they also could not let reason (or as they prefer to call it,
"thinking") be conceived as a set of psychological
operations, since that would subject reason's laws (logic) to
more basic psychological or psychophysical laws. Already in his
(1887), Natorp objects to such psychologism (though he does not use
the term) on the grounds that science and knowledge, and the very
notion of objective truth these presuppose, would be rendered
senseless if grounded in the *subjective* experience of the
thinking or knowing psyche (see esp.
 Section 4).
 The chief task for any account of Natorp's philosophy, then, is
to make sense of his notion of rational autonomy.



Beyond the issue of reason's autonomy or priority, another
central issue for Natorp is reason's history; again, this is a
concern typical of the Marburg School generally; one of its
peculiarities is the quasi-Hegelian insistence upon the integration of
the systematic and historical moments of philosophy. Cohen wrote major
essays on Plato (Cohen 1866, 1878), and Natorp's early work
concentrated on what the Marburgers considered ancient and early
modern anticipations of the critical philosophy. Then there is
Natorp's *magnum opus*, *Platos Ideenlehre* of
1903, in which he simultaneously develops a "critical"
interpretation of the theory of forms and an argument for the order of
the dialogues, all conceived as an "Introduction to
Idealism" (cf. Laks 1994, 2003).



During his life, Paul Natorp was overshadowed by his mentor, Cohen,
and after his death, by the more glamorous Cassirer. For decades, if
he was mentioned at all, one remembered his controversial Plato book,
or, perhaps, his other contributions to the study of Greek thought
(cf., e.g., Stewart 1909; Owens 1978; Gaiser 1969). But Natorp has
been further obscured by the general eclipse of neo-Kantianism for
most of the twentieth
 century.[8]
 It has only been since the late 1970's, with the revival of
European interest in the Marburg School, and especially through the
work of Helmut Holzhey since the
 1980's,[9]
 that Natorp has reappeared on the philosophical scene and the unique
features of his thought have become more plainly distinguished from
 Cohen's.[10]
 Holzhey's unearthing of several heterodox, critical texts
(Holzhey 1986: vol. 2) from the *Nachlass* suggests that Natorp
himself had suppressed them, either "for the sake of maintaining
the unity of the 'Marburg School,'" or because he
did not always think himself able to provide an alternative to a
particular Cohenian
 thesis.[11]
 Yet, despite the Marburgers' loud assertion of the centrality
to their philosophy of science and its history, most recent interest
in Cohen has focused on his late works in the philosophy of religion;
and despite Natorp's allegiance to Cohen's generally
scientistic program, much ado is made of his purported
"ontological turn" (cf., e.g., Brach 1996: 190, ff.;
Stolzenberg 1995, ch. 5) away from epistemology. By contrast, this
article focuses on Natorp's thought in the areas to which he
after all devoted most of his career as a member of the Marburg
School: philosophy of science, history of philosophy, and
philosophical psychology; it does not deal with his politics or
pedagogical theories (see esp. Willey 1978; Jegelka 1992; Natorp
1905), philosophically informed though they are (Cohen 1914: 470).


## 2. Transcendental method in the philosophy of science



It is a commonplace of nineteenth-century German intellectual history
that with the collapse of post-Kantian Idealism, philosophy ceded its
claim of scientificity to the positive
 sciences.[12]
 The special sciences made rapid and startling progress, continually
adding to the store of human knowledge. Philosophy, meanwhile, seemed
to have lost its way, and many thinkers pinned their hopes for a
rehabilitation of philosophy on a return to Kant. The Marburg School
in particular interpreted this to mean that philosophy should orient
itself with respect to the sciences, rather than strive--as
German Idealism had--to forge a scientific system of its own,
independent from the results of the positive sciences: only in this
attenuated sense would philosophy be "scientific". For all
that, Natorp by no means conceived philosophy as a humble handmaiden.
On the contrary, its task is to discover and establish the highest
principle(s) of rational understanding, and thereby the principles not
only of the sciences, but also of ethics and aesthetics, in short, of
all the domains of human culture (cf. Cohen 1902: 443). It must
however take science as its primary object of inquiry because science
represents the paradigm of knowing (*Erkenntnis*). Only a
critique of science can therefore elucidate rationality or, as the
Marburgers call it, the "logic" of thinking, for it is
only in science that we can most reliably witness thinking at work,
successfully achieving knowledge. Thus the question of the
"concept of science" becomes "the chief question of
logic and the foundational question of philosophy" (Cohen 1902:
445). The Marburgers identify the unifying principle of science and
ethics in
 particular[13]
 as the concept of law (*Gesetz*), and, as Cohen puts it,
"it is the business of logic to determine the meaning of law, or
rather, the meanings of law" (Cohen 1902: 445).



Natorp and Cohen find general affirmation of this train of thought in
Kant's project of seeking the conditions of possibility of the
"fact" of mathematical natural science (cf. Kant
*Prolegomena*). However, the similarities end there, for by
rejecting or modifying several basic aspects of Kant's
philosophy, they also end up with a radically transformed conception
of the nature of scientific experience and the meaning of knowledge.
The first of their modifications stems from an anti-psychologistic
critique of Kant himself, namely of what they see as a confusion in
the first *Critique* between the task of a transcendental
grounding of the sciences and that of a transcendental logic of human
cognition (Stolzenberg 1995: 25. But compare Holzhey 1984: 137). The
former is in their view the genuine critical enterprise, for it
promises to reveal the autonomous sources of objective knowledge,
whereas the latter threatens to trace science back to psychological,
and therefore contingent, subjective (albeit *a priori*)
 wellsprings.[14]
 Second, they deny any scientific role to intuition as conceived by
Kant, either pure or empirical. Partly this is a result of their
anti-psychologism, which forbids them from grounding the objectivity
of science in the subjective faculties of cognition; but it is also
because they see, with Kant, the essence of thinking in its activity
and spontaneity, whereas intuition (at least as defined by Kant) is
passive and receptive (cf., e.g., Kant, *Kritik der reinen
Vernunft* (*KrV*), A68/B93). Hence, intuition thus
conceived threatens to introduce a heteronomous, and therefore
rationally unacceptable, factor into science. Finally, the Marburgers
follow their German Idealist predecessors in dismissing all talk of
things in themselves, conceived as things existing independently of
knowledge. We can see how these three important modifications of
Kant's philosophy stem from the same basic concern with rational
autonomy. For reason to be autonomous, its activity must be
spontaneous; but this spontaneity cannot be conceived of
psychologically, because human cognition as a matter of fact has a
passive, and therefore heteronomous, intuitive element, namely
sensibility. Furthermore, things in themselves can play no explanatory
role here because they are *ex hypothesi* alien to reason.



These modifications have two radical consequences for Kantian
doctrine, consequences that characterize the Marburgers' own
theory of science and cognition. The first is a new conception of
science; the second is a new conception of the categories (see
 Section 4).
 It might seem that science, as the achievement of an autonomous
rationality, must fail to be objectively true of the world, if
reason's autonomy implies that it can have no intuitive,
receptive link to the world via sensibility. How in general could the
rationally constructed system be related to experience or constrained
by it? How in particular could physics, the science of motion in space
and time, be possible if the pure forms of intuition, space and time,
were banished from science (cf. Friedman 2000: 26, ff.)?



If Natorp often seems to embrace the troubling thesis that science is
not of the phenomenal world, this is because he holds, first, that the
meaning of "phenomenon" is problematic; and second, that
the aspect of science *relevant to philosophy* has nothing to
do with its relation to a phenomenal realm. In this he follows
Cohen's dictum:



> 
> 
> Not the stars in the heavens are the objects which [the
> transcendental] method teaches us to contemplate in order to know
> them; rather, it is the astronomical calculations, those facts of
> scientific reality which are the "actuality" that needs to
> be explained.... What is the foundation of the reality which is
> given in such facts? What are the conditions of that certainty from
> which visible actuality takes its reality? The laws are the facts, and
> [hence] the objects [of our investigation]; not the star-things.
> (Cohen 1877: 27,
>  f.)[15]
> 
> 
> 
> 



The point is that the scientific or epistemic value of, say,
astronomy, is not to be found in what is given and observable by the
senses, but rather in the mathematical exactness of its equations.
These alone constitute and underwrite the truth-value of
astronomy's propositions, and they are solely the achievements
of reason's activity. As noted above, the essential
characteristic of science lies in its objectivity, and that
objectivity is rooted in its lawfulness. It is this formal feature of
objectivity that constitutes the philosophical interest in science,
not the material content of a particular science's theorems; in
other words, the philosophical question is: "How is this
lawfulness possible?" This question is distinct from the
psychological question, "What are the psychological laws that
make it possible for me (as a psychophysical being) to observe a
star?" or the astronomical question, "What are the laws
governing the 'being' of this star in its states and
properties?"



Hence, it is not so much the case that science on the
Marburgers' conception loses all traction on the phenomenal or
"actual" world, as that they are asking an entirely
different question. While for Kant himself such traction is the only
warrant that we are cognizing a genuine object, for Natorp the nexus
of science and apparent reality is irrelevant to the spontaneous,
legislating factor of science that is the activity of reason alone and
therefore of paramount interest to philosophy. How such essentially
subjective application of categories to sensible phenomena in fact
happens is a problem of psychology, not philosophy, to investigate.
Thus we must be very careful in interpreting the Marburg talk of
"scientific experience": it is not experience in general
or psychological (subjective) experience (*Erlebnis*), but
scientific (objective) experience (*Erfahrung*) which is the
"fact" whose transcendental sources philosophy is to seek
(cf. Natorp 1910c: 13). Yet we must *not* in turn take this
scientific "experience" to mean "experience cleansed
by experiment" (to paraphrase
 Helmholtz[16]
 ): experiment by definition obviously remains empirical. Rather, by
"scientific experience" Natorp just means the
"legislative" act of categorial "Grundlegung",
of
 "hypothesis".[17]




By the end of the nineteenth century, it was obvious to any informed
observer of science that its categorial structures were in fact
hypothetical and dynamic: the fact of scientific experience could no
longer be taken as the essentially complete edifice of Newtonian
physics, as Kant had done. In Natorp's rewording of Kant,
science is not a *factum* at all, but a *fieri*, i.e.,
not an accomplished deed, but an ongoing doing (cf. Natorp 1910c: 14).
Hence, what makes science scientific--i.e., productive of genuine
knowledge--cannot possibly be founded on a set of fixed
(physical) principles, analogous to mathematical axioms, the certainty
of which permanently grounds its theorems. Instead, the Marburgers
argue, the essence of science can only reside in its *method*,
i.e., in the regular and regulated manner of its progress. And since
this scientificity is equivalent to objectivity or lawfulness,
transcendental critique must determine the relation of lawfulness to
method.


## 3. Method and hypothesis



In his memoirs, Hans-Georg Gadamer calls Natorp, his doctoral
supervisor, a "*Methodenfanatiker*" (Gadamer 1977:
62). By this Gadamer means that Natorp, for most of his career,
focused on the methodical aspect of thinking to the point of reducing
thinking to method. To understand this riddling statement, one must
take into account Natorp's interpretation of the word,
"method". He writes:



> 
> The word "method", *metienai*, implies not a mere
> "going" or movement in general; nor, as Hegel believes, a
> mere accompanying [going-with]; rather, method means a going towards a
> goal, or at any rate in a secured direction: it means
> "going-after"
>  [pursuit].[18]
>  (Natorp 1912c: 199-200)
> 



The directedness towards a goal which Natorp claims is implied by
"method" illuminates one of two
 senses[19]
 in which his philosophy is idealistic, namely that science (and the
other activities of culture) are guided by regulative ideas or
limit-concepts (*Grenzbegriffe*). Ideas, as Kant argues in the
Transcendental Dialectic, are *a priori* concepts whose source
lies in pure reason alone. Their only legitimate--though
indispensable--theoretical use is to regulate the
understanding's cognition of objects: reason sets down the
conditions under which the understanding's activity will have
achieved its ideal completion in the systematic interconnection of its
cognitions, i.e., in an ultimate science. Reason thereby offers the
understanding a rule--viz. maximal scope and maximal internal
systematicity--against which any actually achieved system of
science must be measured; and because human finitude makes it
impossible in principle for any actual system to attain the ideal
maximum, reason also spurs the understanding on towards ever new
discoveries and
 reorganizations.[20]




While Natorp often seems to blur the distinction between Kantian
categories and ideas, collapsing them both into
"hypotheses" (see below), there is one notion that does
function as an ideal: the *Ding an sich*. According to Natorp,
the thing in itself, properly conceived, is a "pure
limit-concept [*Grenzbegriff*], which merely delimits
[*begrenzt*] experience in its own creative legislation"
(Natorp 1912c: 199); more precisely, the thing in itself is not some
mind-independent *X*, but rather an *X* necessarily
implied by the fact of scientific progress, namely the
"comprehensive sum total [*Inbegriff*] of scientific
knowledge" (Natorp 1918a: 19). Because science is an activity of
reason alone, and the thing in itself is a rational posit necessary
for that activity, it is no longer in conflict with the postulate of
reason's autonomy. Given an object of scientific cognition, the
cognition is conceived as a process never "definitively
concluded", as Cohen says; rather, "every true concept is
a new question; none is a final answer" (Cohen 1885, cited at
Natorp 1918a: 19). Natorp comments: "Just this is the meaning of
the thing in itself as *X*: the infinite task" (Natorp
1918a: 19). In other words, the thing in itself is the ideal of an
object exhaustively determined by concepts, that is, completely known.
As with Kant, however, our cognitive finitude means that the process
of conceptual determination can only approach this ideal
 asymptotically.[21]
 This pursuit of total determination is what Natorp calls
"method", the pursuit of science.



This brings us to the key notion of "hypothesis". The
pursuit of science--its "method" in Natorp's
special sense--proceeds by hypothesis. Sometimes he puts it more
pointedly: hypothesis *is* method. Since method is for him a
"going-after" or pursuit of the "perpetually distant
goal" (Natorp 1910c: 97) or *focus imaginarius* of
complete objective determination, Natorp interprets
"hypothesis" in a correspondingly active sense. He takes
the term "hypo-thesis" quite literally as a
"setting-down" or "laying-under", or as he
puts it, a "*Ge-setz*" or
"*Grund-legung*" (cf. Cohen 1902: 449; 1916: 308,
ff.). These glosses all emphasize the activity of hypothesis: it is
less a posit than a positing, an act by which thinking proceeds and
becomes experience. Natorp writes: 



> 
> The risk [*Wagnis*] [of hypothesizing] is inevitable if the
> process of experience should begin and continue moving: just as my
> foot must take a stand if it is to be able to walk. This taking a
> stand is necessary, but the stand must in turn always be left behind.
> (Natorp 1912c: 203)
> 



The act of hypothesis has two
 aspects.[22]
 First, hypothesis as law (*Gesetz*) or groundwork
(*Grundlegung*) is the transcendental foundation for scientific
experience, i.e., for the activity of legislating and thus rationally
understanding the phenomena. The "phenomena" in question
are not however the sensible phenomena of subjective, psychic
experience (*Erlebnis*), but are instead themselves already
constructions or interpretations. These constructions in turn are
founded on hypotheses of a lower order, viz. on specific concepts
formulated to transmute particular subjective experiences into
objective knowledge. To take up our earlier example, when the
astronomer speaks of planets and their laws of motion, he is speaking
*objectively* of *scientific* phenomena, as opposed to
the *subjective* appearance of *sensible* phenomena to
you or me. Therefore, on Natorp's view, strange as it may sound,
the phenomenon "Mars" is an hypothesis, an object
certainly, but for all that an ideal and never fully determined
*thought*-object; moreover, the motion of this object, too, is
ideal: it can be calculated with the utmost exactitude. It is these
two hypotheses--the concept, "Mars", and the laws
governing its motion--that alone are objective, and susceptible
to knowledge; the reddish speck in the sky is merely a subjective
appearance, of which there can be no genuine (astronomical)
science.



To pull our strands together, thinking in the strict sense is
scientific thinking, for it alone is generative of knowledge, i.e.,
objective truth. Science (and therefore knowledge) as a matter of fact
evolves through time: science is a *fieri*. However, this
evolution or *fieri* is not unregulated, but moves in a
continuous pursuit of ever more precise determinations of experience:
this pursuit is literally called "method". These
determinations of experience just are the objects of science. The
philosophical task therefore is to analyze the condition of
possibility of the *regularity* of this methodical
determination of experience. Natorp (like Cohen; 1902: 449) identifies
this condition as hypothesis, interpreted as law (*Ge-setz*,
posit); experience in the strict sense is only possible given a law
(*Gesetz*) that functions as its interpretational groundwork or
foundation (*Grundlegung*). The first hypothesis or primal
posit then must be the law of lawfulness, viz., the rational postulate
that experience, in order to be *Erfahrung*, and not mere
*Erlebnis*, must accord with law, i.e., be grounded on a
rational foundation (cf. Natorp 1887: 285; 1911e; 1917: 246). This
categorical imperative, that all its experience fall under law, is the
originary act of reason wherein lies its ultimate autonomy; it is the
regulative principle of the continuous, orderly flow of
 experience.[23]
 As a general, purely formal law it regulates the particular
hypotheses, which in turn generate or ground particular objects of
*Erfahrung* (such as "Mars",
"electricity", "atom", or
"gravity") in the regulated process of their ever wider
and ever more rigorous determination. *How* it does this is a
separate problem, one that Natorp attempts to solve through his system
of categories, treated in the next section.


## 4. Thinking



Just as "experience" for the neo-Kantians is restricted to
"scientific experience", so too is "thinking"
restricted to "scientific thinking;" in fact, Natorp
virtually conflates experience and thinking. His view of science as
the progress (*Gang*) of method via hypotheses regulated by an
ideal of complete objective determination leaves the problem of what
exactly these hypotheses do and how they do it: the problem of Marburg
"logic". As Cassirer points out, Natorp's conception
of logic presses the traditional "analytic" doctrines of
concept, judgement, and syllogistic into the background in favor of
the "synthetic" logic of the genesis of mathematical and
physical
 objectivity.[24]
 Natorp's logic is therefore called "genetic;" it
tells how thinking lawfully generates or synthesizes the unities that
are its objects of knowledge. As such however it amounts to an
analytic reconstruction of thinking's synthetic construction of
its objects (Natorp 1887: 283). He writes:



> 
> It is true that thinking operates [*schafft*] (in the sciences)
> in accord with secure laws of synthesis, although to a large extent it
> is at the same time unconscious of these laws. [As science] its
> interest is not primarily these laws, but rather the scientific
> content which is generated in virtue of them. Thinking is in each case
> focused upon its particular object. An entirely new level of
> reflection is required to investigate, not the particular object, but
> the laws in accordance with which this and any scientific object in
> general first constitutes itself as an object. This new kind of
> reflection we call "logic". (Natorp 1910c: 10-11)
> 



In other words, the scientific hypotheses or laws (*Ge-setze*)
by which science methodically, synthetically progresses are not
transparent to rationality *qua* scientific; instead, they must
be analogically retraced by a critical "logic".

 This
is because the scientist is, and should be, solely concerned with the
laws in accordance with which the phenomena (objectively, not
psychologically conceived, see
 Section 2)
 may be coherently ordered, and thus objectively determined.
Scientific thinking is the "legislating" (hypothesizing)
of these laws; logic--philosophy--lays bare the laws in
accordance with which this legislation occurs: reason's
constitution as opposed to its statutes.


For Natorp, as for Kant, thinking is activity, doing: the technical
term is "function". This word, however, is as ambiguous as
it is central to the Marburg account of
 thinking.[25]
 Occasionally, "function" seems to mean something like
subjective, psychic act, and as such is excluded from epistemological
consideration (Natorp 1887: 266); usually, however, it signifies the
spontaneity of thinking, not in psychological terms, but as the
rational act of hypothetical legislation discussed earlier. In this
second signification it is sometimes connected with
"function" in the mathematical sense, or else mathematical
functions are adduced as paradigmatic of the functional conception of
 thinking.[26]
 The standard sense of "function" for Natorp, then, is
that of an act or "operation" of thinking, where this
means laying down a hypothesis. Since the hypothesis is always a
concept, a generality that imposes a unity upon a phenomenal manifold,
we can understand "function" more precisely as the act of
unification or synthesis. 



For Kant, too, the term, "function", is always connected
to the categories' spontaneity and their synthetic activity;
further, he holds that true *cognition* (*Erkenntnis*)
can only occur if the synthesis in question "schematizes"
representations given in intuition (cf. Young 1992; Friedman 1992,
2000). By contrast, Natorp understands *all concepts* as
functional, i.e., as categorial, since all of them, including the
concepts of space and time, are thought-operations serving to unify a
 manifold.[27]
 As we saw above, Natorp rejects any notion of intuition as a passive
faculty receptive of a given sensible manifold (cf. Natorp 1912c:
201). Instead, he interprets intuition as itself an act of synthesis,
i.e., as a generation of unity. He argues that a critical account of
knowledge is not justified in presupposing some object conceived as
existing radically independent of mind, and which then somehow affects
it via intuition: to do so would be tantamount to an intolerable
"metaphysicism" (Natorp 1912c: 202). Rather, Natorp claims
to find in the first *Critique* itself the basis for his view
that intuition is not a factor "alien to thought
[*denkfremd*]", but that it merely signifies a different
*aspect* of thinking, viz. that aspect in which a fully
spatio-temporally determined object, rather than merely a law, is
thought (Natorp 1912c: 204; Natorp 1910c: 2-3). This
"fulfillment [*Vollzug*]" of objective thought 



> 
> 
> in each of its stages requires rigorously unambiguous determination,
> but determination always with respect to the lawful functions of
> thinking itself: determination of the particular, of quantity, of
> quality, in accord with the relation of causality and its laws.
> (Natorp 1912c: 204; Natorp 1887: 280) 
> 
> 
> 



On this view, far from being separate from and opposed to thinking as
they seem to be in the first *Critique*, space and time, as the
forms of intuition, are originary thought-acts that make possible the
determination of any object whatsoever. They are hypothesized,
synthetic manifolds, or--more precisely--unified, ordered
manifolds of points or "positions" (*Stellen*) into
which any object must first be integrated if it is to undergo any
further determination as to quantity, quality, etc. (Natorp 1912c:
203; 1887: 280. Cf. esp. 1911e: 76-77; *PI*, 159, ff;
366, ff.). Thus, only in virtue of these various synthetic procedures
of progressive determination, which Natorp calls
"objectivation" (i.e., object-formation), can a phenomenon
even appear. But how does it appear? Since intuition and thinking are
being analyzed here entirely at the "functional" level,
the phenomenon evidently does *not* appear as a sensible
object, i.e., one that may be assigned a unique set of spatio-temporal
loci, and that then may serve as a carrier (*Trager*) of
all further determinations of quality, quantity, or relation.



This then raises the following pressing question: if, as he argues,
intuition is itself a synthetic activity, what "matter"
does it synthesize, if not the sensible manifold? Natorp is
distressingly elusive on this point, even in his explicit discussions
of the status of time and space in science (cf. Natorp 1910c: Chapter
7). The following is clear, however. Like Kant, Natorp understands
thinking always to be thinking an object. For Natorp, however, this
means "constituting", "constructing", or
"objectivating" the object. But since he (re)interprets
these objects as non-sensible phenomena, he also interprets space and
time non-psychologically, i.e., as non-sensible. They are not the
forms of sensible intuition, but the ideal system of dimensions (three
spatial dimensions plus time (cf. Natorp 1910c: 303, ff.;
397-398), conceived as 



> 
> 
> structures of a purely mathematical kind, which nonetheless go beyond
> mere number, in virtue of the general relation to existence [that is]
> contained in their very concepts. (Natorp 1910c:
>  341)[28]
> 
> 
> 
> 



Thus a very crucial distinction must be made between two levels of
phenomenality and of objectivity, which for the purposes of this
article shall be called "first-order" and
"second-order" (cf. Stolzenberg 1995: 25). A first-order
phenomenon is the psychic, *subjective* appearance that Natorp
tacitly acknowledge has a basis in sensibility, and which he calls the
"*Phanomen letzter Instanz*" or the
"phenomenon of final authority" (Natorp 1887: 273, 274;
1913b:
 192);[29]
 this first-order phenomenon is a "*Vorstellung*",
or "representation", i.e., a doxic phenomenon (Natorp
1887: 266, 267; esp. 273). Hence it cannot be the referent of
knowledge or science, since science does not concern itself with doxic
appearances *as such*, but the *objects* (or
objectivities) which appear in or through the appearances (Natorp
1913b: 193). 



But how are we to understand this "appearing" of an object
"through" the doxic appearances? What, precisely, is the
relation between the first-order and second-order
"phenomena"? In the places where he explicitly mentions
sensibility in the concrete, psychological sense (Natorp 1913b: 193),
Natorp conceives it as never conveying or "giving" the
mind an object, ready-made. Rather, "what" sensibility
gives is so entirely indeterminate and uncoordinated that it cannot
even be called a manifold; whatever the chaos of sensibility may be,
Natorp conceives it as nothing more than a *task*
(*Aufgabe*), *problem*, or *demand*
(*Forderung*) for objectivity, that is,
 objectivation.[30]
 Since no thing (no object) is ever given in sensibility, any object
is only ever constructed, and can only be known *qua*
construction, viz. as an instance of its constituting law. 



Natorp likens this problematic relation of first-order phenomenality
and second-order objectivity to solving for *X* in an equation
(Natorp 1887: 258, 262). If the solution(-set) of *X* is the
object for which thinking is to solve, then the sensible appearance is
analogous to the notational cipher, "*X*", itself,
since what-has-not-yet-been-experienced is simply
what-has-not-yet-been-constructed. Moreover, just as in solving an
equation one can only determine the *X* in light of other known
quantities assumed in the equation, one must in the same way establish
the determinations of the problematic object in light of other
objectivities (laws) that are assumed (*ge-setzt*). No such
objectivities are ever granted absolutely, of course, but only
relatively, namely with respect to the particular problem. They, too,
are always susceptible to becoming problems in their turn. Therefore
no complete solution--no total determination of the
object--can be achieved for any *X*, except
asymptotically. While the fully determinate object itself thus remains
a forever unreachable *focus imaginarius* (see
 Section 3),
 it is, by the same token, always at least partially determined. And
it is this *partially determined objectivity* as itself a
(non-sensible) object of thinking that Natorp considers the
second-order phenomenon, even though he will usually just call it a
"phenomenon", *simpliciter*. This
*scientific* phenomenon, as an objectivity that is
progressively constituted by a dialectic between hypothesis and
calculation, entirely loses any sense of "appearance".
This reconception of the phenomenon of mathematical physics finds an
analogue in geometry's replacement of constructions "in
intuition" by purely logical deductions from *Grundlagen*
(or "functions" in the sense of "hypothetical
act") as epitomized by Hilbert's *Grundlagen der
Geometrie* (cf. Friedman 1992, Chapter 1; Hilbert 1999), a book
cited with approval by Natorp (1910c: 4) and Cassirer (2000: 99, f.).




The question now is: what makes the second-order phenomenon a bona
fide objectivity, in contrast to the first-order phenomenon? Whereas
the first-order phenomena constitute private, lived subjectivity, not
open to prediction or even adequate description, Natorp's answer
is that the second-order object is constructed in accordance with laws
of thinking, which as laws are in their very nature objective, i.e.,
universally valid for any thinker. Therefore objects
(*Gegenstande*) lawfully determined will in principle be
rationally transparent to any other thinker, i.e.,
"objective" (*objektiv*,
*gegenstandlich*). Any such lawful objectivation or
object-formation just is knowledge or science, in the sense of being
objectively think*able*. These laws of constitution are in turn
hierarchically arranged: the highest, most general laws are those
governing all possible thinking, and thus the generation of all
experience. These are followed by mathematics, and by all the
mathematically "exact" sciences. As was shown in
 Section 3,
 Natorp conceives these laws (*Ge-setze*) as
*essentially* "hypothetical", that is, as
categorial posits. With the apparent exception of the basic logical
laws (e.g., the indispensable "law of laws"), *all*
such laws are in principle revisable (which is chiefly why the
determination of objectivities must be conceived as asymptotic)
(Natorp 1887: 274; 276-277).



Hence, philosophy, as transcendental critique (see
 Section 1),
 is "sharply distinguished from any kind of
'psychologism'" and "maintains its rigorously
*objective* character" (Natorp 1912c:
 198).[31]
 Why? Because its point of departure is the *objective*
"formations" [*Gestaltungen*] of human culture,
*as objectivities*, not as products of subjective psychological
operations (Natorp 1912c: 198). In other words, philosophy always
begins from the second-order phenomena.


## 5. 'Critical' Psychology



Although on Natorp's view, the first-order phenomena of
subjective psychological experience (*Erlebnis*) elude
scientific understanding altogether, he wrote two significant works on
what he calls "critical" psychology. Pure,
unconceptualized subjectivity is the immediate condition of the
psyche; but the "*logos*" of science just means
"objectivity". Hence, Natorp argues, there can be no
"psycho-logy" in the strict sense of the term, for it
would amount to the objectivation of subjectivity, and hence to the
annihilation of the very thing a psychology would want to study: the
psyche in its "natural" state (cf. Natorp, 1887: 283).
Although there is no 



> 
> 
> immediate access to the immediacy of psychic experience, [yet] it can
> ... be approached by a [methodical] regression from its
> objectivations, which must therefore [first] be secured in their own
> purely objective justification. (Natorp 1912c: 198) 
> 
> 
> 



This is "critical" psychology in a nutshell. What Natorp
means is this: there can be no *objective* "access"
to immediate psychic experience, which is absolute subjectivity.
Nonetheless, we can gain access to a *mediated* subjectivity,
namely through the objects that have already been objectivated in
(scientific) thinking.



Thinking, as we saw in
 Section 4,
 moves forward in a "synthetic" fashion from the less to
the more determinate. That is, in taking up a second-order phenomenon,
thinking works on an object that retains, *qua* appearance
(phenomenon), an as yet undetermined subjective, doxastic residue. It
brings (some of) this residue under laws, thus determining the object
further: it is now better known and scientifically understood. Now,
instead of seeking the constitutive legislative framework that
transcendentally "grounded" that determination (the task
of critical philosophy), critical *psychology* performs a
"methodical regression", viz., by undoing the
object's most recent determinations, thus revealing its prior,
relatively more "subjective" phase.



In this way, Natorp thinks, antecedent stages of our latter-day
science can be reconstructed and temporarily resuscitated. This
project complements critical philosophy's logical project, by
allowing reconstruction of successive phases of objectivity, thus
making our current knowledge more transparent to *reflective
 reason*.[32]



## 6. History of Philosophy



We finally turn to the Marburg thesis that philosophy, as philosophy
of science, must also be the philosophical history of science. For
science, as a *fieri* (a do*ing*) evolves over time;
hence the activity of its basic functions and the regulated mutation
of its laws can only be observed through time. Yet this historical
tracing of the progress of science must be philosophically informed,
that is, grounded in the transcendentally isolated system of basic
functions. As mentioned above, Natorp holds that the entire value of
the transcendental method is normative: having laid bare the
categorial functions in their purity, science can be judged as to its
rigor, i.e., its submission to rational legislation. The Marburgers,
with this criterion in hand, enthusiastically apply it in praise and
blame.



A historiographical commonplace of neo-Kantianism has it that the
labor of grounding the sciences was divided between the Marburg and
Southwest Schools, the former attending to the natural sciences, the
latter to the human sciences or *Geisteswissenschaften* (cf.
Oesterreich 1923: 417). Recent scholarship has complicated this
picture, reminding us of Rickert's contributions to philosophy
of natural science (cf., e.g., Rickert 1902; 1899), and noting that
the Marburg School, too, has a theory of history (esp. Edel 1994; Laks
1994; Lembeck 1994). Already Cohen argues that the disciplinary
division between systematic philosophy and the history of philosophy
is artificial and harmful; he insists that "the study of
philosophy requires the connection of the systematic and historical
interest" (Cohen 1902: 440).



Still, the common view, if one-sided, is not wrong, for the Marburg
theory of history has a very different starting-point than does the
Southwest School. Unlike Rickert and Windelband, Cohen and Natorp do
not begin their theory of history from the "fact" of
historical science, in the way they begin their theory of natural
science from the "fact" of mathematical physics. When they
speak of history, they mean, on the one hand, the history *of
science*, and on the other, the history *of philosophy*,
properly construed, namely as the critique of science. Only
secondarily are they interested in political, economic, or social
history, and only insofar as it advances their primary
 project.[33]




The Marburg conception of genuine philosophy as *in the first
place* a transcendental logic of natural science (cf. Cohen 1902:
445) therefore restricts history to a history of "scientific
 idealism".[34]
 In rejecting the view that scientific progress is better understood
exclusively from a "systematic" perspective,
"detache[d] ... from its historical bonds", (Cohen
1902: 439) Cohen remarks that the "very value and security of
science is rooted in its own history, connected, as it were, with the
general history of mind [*Geist*]" (Cohen 1916: 310).
This sounds odd since we have heard again and again that science is
rooted in its *method*, but now are told it is rooted in its
history. Perhaps the paradox is only seeming, for there is an intimate
connection between the Marburg School's notion of hypothesis as
the active posit of mind, on the one hand, and its notion of science
as essentially historical, on the other. Their conception of the logic
of science as the dynamic *Gang* of categorial hypotheses
implies that science can only be grasped developmentally, i.e.,
historically.



The Marburg view of that history differs in two important respects
from Hegel's, with which it might otherwise seem to have much in
common: first, it is not based upon a sequence of conceptual
contradiction and resolution; second, the history of science's
development is relativistic, that is, in principle incapable of
achieving an "absolute" resolution (Natorp 1912c: 211,
ff.). Let me focus on the first of these differences. For Hegel,
history is the *linear* evolution of *Geist*'s
self-knowledge through time; the further to the right you go, the more
advanced the stage of (self-)consciousness. These stages--the
"phenomena"--of *Geist* are inseparable from,
indeed just are their cultural manifestations. Cohen and Natorp, too,
take genuine history to be the history of rational self-consciousness,
but for them this simply means reason's transcendental,
reflective consciousness of the basis of science, that is, method.
This principle of lawfulness is in itself unchanging, eternal,
atemporal; it is not expressed "in" phenomena, but instead
makes possible and generates phenomena as such; and indeed (as we saw
above) generates time itself as a condition of the possibilty of
phenomena. Because its object--this rational insight into
reason's own principle--is essentially detached from time,
history for the Marburg School is not conceived with respect to time.
Of course science develops in time, and may be tracked diachronically
along a time-line, yet its innermost core is the self-same atemporal
idea, around which science *circles*, its progression
represented by ever wider, but concentric
 orbits.[35]
 Thus the history of science is itself *ideal*, in the sense of
focusing solely upon those moments of reflective illumination when
science becomes self-conscious--through philosophy--of its
rational foundation or transcendental nucleus. Cohen writes: "In
the history of every science the history of scientific reason in
general always fulfills itself concentrically" (Cohen 1916:
310). He considers the fact that each of these moments of
self-consciousness must occur in concrete circumstances and have a
unique point on a real time-line to be as obvious as it is
 irrelevant.[36]




The transcendental nucleus is method, and method is the meaning of
idealism; hence, idealism is born when reason becomes self-conscious
of its thinking as methodical and
 scientific.[37]
 Since this birth has a historical locus, Cohen argues,
"idealism's historical origin ... conditions idealism
through its connection with the methodological foundation of science
no less than its material origin in methodology" (Cohen 1916:
 309).[38]
 Put another way, idealism connects with its methodological foundation
*by* connecting with its historical origin (cf. Cohen 1902:
450). It follows that idealism has two related historical tasks: the
primary task is to open and maintain a direct avenue to its origin.
This involves the secondary task of retracing previous scientific
connections to that same primal idealism, which alone can serve as the
criterion of the "relatedness [*Verwandtheit*] of
different phases of science" (cf. Cohen 1916: 310). The history
of idealism is therefore not of its evolution (as is the history of
science) but of its rebirths.



The history of science is a history of often contradictory or
incommensurable theories, each of which is represented in
Cohen's image as a ring. Nonetheless, as scientific, the variety
of theories all express the same central, unitary activity of reason:
positing hypotheses. Because of this constant unity of scientific
reason, a "continuous connection of reason and the fundamental
forces [*Grundkrafte*] of its history is required"
(Cohen 1916: 310). By "fundamental forces" Cohen just
means Greek
 antiquity,[39]
 specifically Plato:



> 
> Plato is the founder of the system of philosophy ... because he
> founded logic [in the Marburg sense], and thereby the system of
> philosophy. He is generally to be understood as the founder of
> idealism. But the word, "idealism", in the whole history
> of culture, in which it has against the odds remained the guiding
> watchword, has only emerged at certain illuminating turning-points
> from an unclear and imprecise meaning. (Cohen 1902: 446)
> 



History's "illuminating turning-points", where
idealism's meaning manifests itself clearly and distinctly, are
the moments when the generative principle of scientific knowledge
shines forth--i.e., when a critical, reflective perspective upon
method is achieved--drawing the mind from its hyperbolic forays
back into the regular orbit of reason, when we realize that we cannot
simply be guided by the things as they appear to us. They are moments
of reason's recollection, rebirth, and self-renewal (Cohen 1916:
309).



Hence the Marburgers consider it of the utmost significance that their
heroes--especially Galileo, Leibniz, and Kant--explicitly
link their conceptions of science back to Plato. As Cohen and Natorp
select and interpret their idealistic predecessors, they see
illustrated in them the crucial *immanent* role of historical
reflection in science, by which it ascends to transcendental
self-reflection upon its methodological foundation (cf. Cohen 1902:
450). As Cohen puts it, "history is ... a sign
[*Wahrzeichen*] of the inner life and growth of all problems of
scientific reason as they emerge out of the root of their
methodology" (Cohen 1916: 310); and that root is, historically,
Plato: "Idealism is the Idealism of the Platonic Idea"
(Cohen 1916:
 305).[40]
 For Cohen and Natorp, "Plato" signifies the organizing
principle of science as a historically unfolding, living enterprise.
To stop reading Plato is to subtract science from its rational core,
and deprive it--not of its method, which it will always have
*qua* science--but of self-transparency of its own
*pure* foundation and legitimacy.



Although history, according to Cohen, "discloses the origin of
idealism from the start", we must rely no less upon our methodic
understanding of idealism in order "to recognize this idealism
correctly wherever it appears" (Cohen 1916: 305). This statement
confirms the hermeneutic inseparability of system and history: each
supports the other. By "systematically" determining
idealism as the method of science, we enable idealism to recognize
itself in its historical manifestations; these manifestations, in
turn, furnish the "fact" of science to be systematically
determined. This reciprocity of history and theory informs the
following passage, in which Cohen links Plato with the Marburg
program.



> 
> The concept of idealism must be determined logically. This
> determination is the profoundest task and the highest content of
> logic. Plato found this determination by establishing logic's
> connection to science, and thus grounding logic. The determination
> lies in the concept of the Idea [i.e., Platonic form], the
> misunderstanding of which led necessarily to the indeterminacy of the
> notion of idealism itself. *What does "Idea"
> signify?* (Cohen 1902: 447)
> 



In other words, to succeed in the methodic or "logical"
determination of idealism, we can do no better than ask the historical
question of how Plato "hits upon this determination".



This is precisely the task Natorp sets himself in *Platos
Ideenlehre* [*Plato's Doctrine of Ideas*]. True to
the Marburg view that idealism can only be understood by retracing its
development, Natorp simultaneously reconstructs the idealistic meaning
of the dialogues and the "logical" order in which they
must have been
 composed.[41]
 He takes a double-pronged approach by arguing, on the one hand, that
the Platonic *ideai* (forms or ideas) are in fact correctly
understood to have a "critical" sense; and, on the other
hand, by explaining why this critical intent of Plato (and by
extension of all other critical idealists) was misconstrued not only
by Aristotle and virtually the whole tradition, but even, at times, by
Plato himself. That mistaken reading consists in taking the ideas to
be substances, i.e., really existent things, which however have a
purely noetic, or rather, noumenal character; whose appearances (the
"particulars") may be sensible, but which in themselves
exist "separately", open only to a quasi-mystical vision.
Kant himself of course understood Plato in just this way, chastising
him for flying beyond the limits of reason on the wings of
intellectual intuition. 



Natorp by contrast argues--over the course of 500
pages--that while Plato may for various reasons talk in a way
that encourages such a reading, his most mature, sober, and
self-critical dialogues support a *categorial* interpretation
of the forms as "hypotheses" in the special sense
discussed in
 Section 3.
 Thus, the problems of how the ideas could exist apart from the world
of real particulars, and whether pure reason has a special intuitive
faculty capable of bridging the gulf, evaporate, once we recognize the
*immanent* operation of the *ideai* as the categorial
 hypotheses[42]
 that are the conditions of possibility of thinking in general, and of
science in particular. Thus Natorp interprets the supreme form, the
form of the Good, as the "law of lawfulness", (see
 Section 3)
 i.e., the unifying source of both theoretical and practical reason,
while the five "great kinds" of the *Sophist* are
seen as mutually implicative logical *Grundbegriffe* or
"root-categories" of all predicative thinking. These
*ideai* are no more separately existent, according to Natorp,
than are Kant's categories: they are not transcendent so much as
they are transcendental. It has been the incapacity of all
(Aristotelian) realists or "dogmatists" to grasp this
distinction that has led to the chronic misunderstandings of Plato and
all other "criticists". 



The Marburg "theory" of history to which Natorp
subscribes, and in light of which he writes *Platos
Ideenlehre*, is this: Plato's moment of insight into the
truth of transcendental idealism (a la Cohen), is followed by
millennia of dark irrelevance, punctuated by shining rings of
recollection, epitomized by Galileo, Newton, and Kant. This picture of
Marburg *Philosophiegeschichtsphilosophie* (cf. Lembeck 1994:
1-2) will strike many as surreal; still, it only seems right to
note the following. Though we must understand the Marburg conception
of history to grasp their motivation for reading and re-reading Plato,
we need not accept that conception in order to appreciate either
Natorp's genetic logic of science or his reading of Plato. As
Lembeck puts it in the introduction to his *Platon in
Marburg*:



> 
> It is not a matter of proving that Plato's philosophy is not
> transcendental idealism; that is so obvious as to be taken for
> granted. It is however something entirely else to show why Cohen and
> Natorp believe that Plato, at least in principle, laid the groundwork
> for this idealism. (Lembeck 1994: 5)
> 



Fortunately for them, we can betray their *idee fixe* of
Plato as the living heart of transcendental idealism without, as they
would think, destroying or dismissing their work. Indeed, one can
perhaps better appreciate the value of Natorp's reading of Plato
if one does *not* think of it as support for Marburg idealism
as such, but simply as an ingenious attempt to make sense of the
relation of ideal form and empirical particular, an attempt that
merely employs the logic of categorial functions as a hypothetical
springboard.