## 1. Life and Works



Born in 1842 in Coswig, Germany, Cohen was raised in a devout family.
His father was a synagogue cantor, and Cohen left *Gymnasium*
in order to attend a rabbinical seminary in Breslau, Silesia (now
Wroclaw, Poland). But he decided against becoming a rabbi, and
enrolled in university first in Breslau and then in Berlin, where he
attended classes taught by a leading light in the history of
philosophy, the Aristotelian scholar and metaphysician Adolf
Trendelenburg. He received his doctorate from the University of Halle,
after which, encouraged by Heymann Steinthal, he
studied *Volkerpsychologie*, a philological and
anthropological investigation of the origins of cultural products such
as art and literature. It was in a journal of
*Volkerpsychologie* and linguistics that he published his
first major work of Kant interpretation, an intervention in
Trendelenburg's and Kuno Fischer's debate about
Kant's Transcendental Aesthetic (see SS2 below). That essay
also marked a decisive turn in Cohen's philosophical
orientation, and after two years in which he wrote on both
Kant's pre-critical philosophy and the *Critique of Pure
Reason*, he was appointed lecturer at the University of Marburg.
Three years later, he was promoted to full Professor, a rank that was
at that time in Germany almost never granted to unconverted Jews in
philosophy departments. It was no coincidence that Cohen's
appointment and subsequent promotion took place during Bismark's
anti-Catholic *Kulturkampf*, a brief period of relatively
liberal attitudes toward Jews. But following Heinrich von
Treitschke's notorious 1879 anti-Semitic attack on German-Jewish
writers and intellectuals, Cohen was compelled to enter the public
debate about the Jews' place in Imperial Germany. His
"Declaration on the Jewish Question" appeared in 1880, and
questions of German-Jewish identity would occupy him throughout his
career (Schwarzschild 1979; Wiedebach 1997, Pts. 4-5; and Beiser
2018). He remained at Marburg for almost four decades. After retiring
from Marburg in 1912, Cohen returned to Berlin in order to teach at a
rabbinical seminary, the Academy of Jewish Sciences. He spent four
years there, writing principally about religious problems, until his
death in 1918.



Cohen's period of philosophical productivity spanned the
duration of the German empire, from the late 1860s until 1918. We can
distinguish three periods in his writing (van der Linden 1988,
205-6; Bonaunet 2004: 22ff). The first, early period is
characterized by Cohen's attempts to develop his own views as
commentaries on Kant. During this period, he wrote *Kant's
Theory of Experience*, *Kant's Foundations of
Ethics*, and *Kant's Foundations of Aesthetics*. The
second period marks Cohen's mature philosophical work, which
took the form of his multi-volume *System of Philosophy*. In
the *System*, Cohen explicitly abandoned central Kantian
doctrines, and presented his views systematically, and as his own,
rather than offering them as interpretations of Kant. The
*System* included *The Logic of Pure Knowledge*, *The
Ethics of Pure Will*, and *The Aesthetics of Pure Feeling*.
(He planned, but never wrote, a fourth part of the *System* on
the psychology of "cultural consciousness." This fourth
part was to provide the systematic foundation for the other three
parts of the *System* [see Adelmann 1968 and Moynahan 2018].)
Finally, although Cohen had been interested in religious questions
throughout his career, in the last years of his life they were his
overwhelming concern. It was during this period that he wrote his
*Religion of Reason Out of the Sources of Judaism*.



However, while Cohen's interests and views evolved over the
course of his career, his philosophy from all three periods
nevertheless exhibits points of deep continuity. All of Cohen's
major works share a profoundly historical orientation. A concern with
the history of philosophy dominates his writing, and he was convinced
of history's continuing significance for philosophy in the
present. But he was also concerned with the histories of those
subjects he took to be philosophy's topics, including science,
ethics, and religion. This concern for history permeates his thought
so completely that even in his systematic works, he prefers to
introduce concepts and theories not by defining them
straightforwardly, but by rehearsing major episodes in the history of
their development. This historically-oriented method was a model for
what later philosophers called *Problemgeschichte* - that
is, the history of the origin, development, and evolution of
philosophical problems. In stands in contrast to historical surveys of
candidate solutions to problems the philosopher conceives as fixed,
unchanging, and unresponsive to a broader philosophical context. (In
Cohen's hands, this historical orientation contributes in no
small part to other aspects of his writing that none of his readers
can fail to notice: its obscurity, repetition, and sometimes
unnecessary length.)



Two further commitments are continuous threads over the course of
Cohen's career and across multiple areas of his philosophical
concern: his idealism and (what Frederick Beiser [2018] calls) his
"methodological rationalism." Cohen expresses his idealism
in different ways over the course of his career. But we may
approximate it as the view that a priori laws of human knowledge
determine what counts an an object for us. For Cohen, this idealism is
intended to capture Kant's insight that we can have a priori
knowledge only of those features of objects that our own mind
contributes to them. But for Cohen, this is not an exclusively Kantian
doctrine. He develops it in part out of his early interpretation of
Plato, according to which we strive to have things conform to our
ideas.



Cohen's methodological rationalism is his commitment to, as
recent commentators have put it, "the *search for
reasons*" (Beiser 2018, 3), the assumption of "the
intelligibility of being" (Renz 2018, 10), and the
"attempt to ground knowledge in critically reflexive,
hypothetical, and self-consciously revisable concepts subject to
justification" (Nahme 2019, 8). Cohen's is not a
rationalism that accepts any substantive doctrine, principle, or axiom
as indubitable or necessarily true. Rather, it is the methodological
commitment never to accept any doctrine, principle, axiom, or any
other representation as brute or unexplainable. Instead, for Cohen we
must always seek reasons for those representations. In Cohen's
epistemology and philosophy of science, this commitment would
culminate in his conception of "pure thinking," that is,
thinking that is free from the influence of anything external to it
(see SS5 below). In his mature ethics and political philosophy, it
is expressed in his view that ethics and the laws that unify a
community "must be seen as an appeal to *justified
reasoning*..." (Nahme 2019, 252) (see SS6 below). At the
same time Christian Dambock (2017, Ch. 4) argues that there is a
sense in which Cohen is an "empiricist," by which
Dambock means that Cohen insists that philosophy must attend to
the facts of history and culture as it finds them. Ursula Renz (2018)
argues that these two senses of "rationalism" and
"empiricism" need not conflict with one another. 



Cohen himself came to think that one commitment above all else unified
his philosophy, from his earliest interpretation of Kant to his mature
*System of Philosophy*. It was his commitment to a
philosophical method he claimed was Kant's, and that Cohen and
his students called the "transcendental method." What
follows is a sketch of that method in Cohen's philosophy: how it
emerged from his interpretation of Kant; how he sought to apply that
method in epistemology and philosophy of science, as well as in
ethics, political theory, and aesthetics; and finally, how he sought
to articulate a view of religion as a necessary counterpart to
philosophy done according to that method.


## 2. The Interpretation of Kant



As we have just seen, Cohen was committed to three ideas: first, an
idealism according to which a priori laws of human knowledge determine
what counts as an object for us; second, his methodological
rationalism, and third, the "transcendental method" (Edel
1988). His early interpretation of Kant reveals these commitments in
nascent form. It also reveals a problem that would occupy him
throughout his later writings on epistemology and philosophy of
science: the problem of explaining the origin of the a priori laws in
human knowledge.



In 1871 Cohen published a long essay, "On the Controversy
between Trendelenburg and Kuno Fischer," and a book, the first
edition of *Kant's Theory of Experience*. They were both
defenses of Kant against objections that Cohen thought badly
misunderstood his views on objectivity and the a priori. Cohen was
responding to an interpretation of Kant in the 1860s commonly held by
figures of the Back-to-Kant movement such as Hermann von Helmholtz and
Cohen's own senior colleague at Marburg, F.A. Lange, as well as
by non-Kantian philosophers such as Adolf Trendelenburg. Very roughly,
these figures thought that Kant held (or that Kantian philosophers
ought to hold) that the character of human knowledge is determined by
both objective and subjective factors. On one hand, there are objects
that exist independently of the subject's mind. These objects
affect the subject's mind, and in so doing contribute the
objective element to the subject's representations. On the other
hand, there are structures in the subject's mind--say, the
forms of human intuition, space and time. Because these structures are
in the subject's mind and thus don't come from experience,
they are a priori. Further, these a priori structures organize the
subject's representations and thereby contribute a subjective,
mind-dependent element to them. But since on this interpretation of
Kant the a priori is subjective, an explanation of knowledge's
objectivity must appeal not to it, but to the objects that exist
independently of the mind.



Cohen thought this interpretation of Kant was wrong, and he thought
that influential objections to Kant depended on it. Cohen was
especially concerned with Trendelenburg's well-known
"neglected alternative" objection to Kant's claim
that space and time are nothing but the forms of intuition. But Cohen
was also concerned with J.F. Herbart's (and in Cohen's own
time, Helmholtz's) contention that Kant thought spatial
representations were innate. Since Cohen thought both
Trendelenburg's and Herbart's objections depended on a
misinterpretation of Kant, he thought those objections failed. He
responded to them by defending an alternative account of the relation
between objectivity and the Kantian a priori (Kohnke 1991,
175-8; Patton 2005). (See Biagioli 2014 and Biagioli 2018 for a
broadly sympathetic account of Cohen's response to Helmholtz in
particular; Hyder 2013 offers a defense of Helmholtz on geometry
against Cohen's criticisms of him.)



Thus *Kant's Theory of Experience* is above all an
attempt to articulate and defend Cohen's alternative
interpretation of Kant's a priori. On that interpretation,
Kant's aim in the *Critique of Pure Reason* is to show
how a priori laws of human thought explain the character of our
experience of objects. For Cohen, because these a priori laws are
necessary, they are objective. So Kant's explanation of
objective experience appeals to them, and not to the effects of any
alleged mind-independent objects.



Cohen argues that there are three different "levels" or
"degrees" of Kant's a priori. He claims that the
first of these is inessential for Kant's philosophy, and
consists in the apparently permanent "metaphysical"
structures we can discover in our own thought by means of
introspection. The second level of the a priori consists in the forms
of sensibility and the understanding, that is, space, time, and the
categories. But the necessity of these forms ultimately derives from
the necessity of the third level of the a priori, because the forms of
sensibility and understanding are "scientific
abstractions" (Cohen 1987 [1871b], 83-84) from that third
level. The third level is thus the most important of the three levels.
Cohen argues that a priori laws in this most important, third sense
consist in the "formal conditions of the possibility of
experience." Or, as he also sometimes puts it, the a priori in
this third sense consists in laws that are "constitutive
of" of the possibility of experience. For Cohen, these
necessary, a priori laws define what an object of experience
*is* for us. (Klaus Christian Kohnke identifies this point
in Cohen as the source of the central Marburg School doctrine that a
priori laws "generate" objects of possible experience
[Kohnke 1991, 178-84].)



Cohen has a striking view of what a priori laws of the third level
actually consist in, and of the possible experience they are
constitutive of. Although he would emphasize this striking view more
in later writings it is nevertheless explicit in the first edition of
his *Kant's Theory of Experience*. He did not think the
third level of the a priori consists in cognitive structures in the
subject's mind, structures we could discover by doing physiology
(as, for example Helmholtz and Lange thought) or by introspection (as,
for example, J.F. Fries and, in Cohen's own time, Jurgen
Bona Meyer thought) (de Schmidt 1976: Ch. 2.3). Rather, he insisted
that these a priori laws were the principles of mathematics and the
fundamental laws of pure natural science, that is, mechanics. Further,
these principles and laws are constitutive of the possibility of
experience in a very specific and, Cohen insists, Kantian sense of
"experience": for Cohen, experience consists in the
theories furnished by the mathematically precise science of nature,
considered as if laid out "in printed books" (Cohen 1877,
27). That is, on Cohen's interpretation, Kant's a priori
is not principally concerned with the cognitive activity of the
knower. Rather, it consists in the laws of mathematically precise
natural science considered independently of - as if
free-floating from - the mind of any particular knower. (At the
same time, Charlotte Baumann (2019) argues that, in at least some of
his writings, Cohen does retain some concern with the role of
sensation in experience.)



Cohen's interpretation of Kant is thus robustly
anti-psychologistic: he thinks any consideration of how the human mind
operates to produce representations is completely irrelevant to a
philosophical account of knowledge's objective validity. In
fact, some commentators have argued that Cohen offers the first
genuinely anti-psychologistic interpretation of Kant's
*Critique of Pure Reason* (Hatfield 1990, 110; Anderson 2005,
298; and Beiser 2015, 466). On a standard account, Cohen's
anti-psychologism was motivated, most fundamentally, by a desire to
ensure that the objective validity of knowledge was not, on his
account, undermined by the subjectivity of sensation (see especially
Edel 2010: 60ff). More recently, Beiser has argued that Cohen's
anti-psychologism was a response to the materialism controversy and
Cohen's religious antipathy to any attempt to naturalize the
human subject (Beiser 2014, 466). Alternatively, Paul Nahme has
suggested that Cohen's anti-psychologism might even have been a
response to the physiological orientation of so-called scientific
racists and anti-Semites (Nahme 2019, 163). 



Despite the robustness of Cohen's anti-psychologism, it is not
always easy to locate in his writings. On almost every page of
*Kant's Theory of Experience* (and later, *The Logic
of Pure Knowledge*) Cohen helps himself to the language of
transcendental idealism and transcendental psychology, giving the
impression of an active, conscious mind, with faculties of sensibility
and understanding that produce the subject's experience of
objects. But, Cohen insists, this language is actually
anti-psychologistic: understood properly, the Kantian's talk of
cognitive faculties really refers to the methods of mathematically
precise natural science. Thus the "faculty" of sensibility
is really just the methods by which the mathematician constructs
spatial magnitudes, and the "faculty" of understanding is
really just the most basic set of concepts the physicist uses to
represent physical objects (Cohen 1885, 586ff.) Kantian theory of
knowledge thus turns out to be the philosophical investigation of the
methods natural science uses to represent objects.


## 3. The Transcendental Method



So Cohen takes the theories of mathematical natural science to be (or
to be paradigms of) "experience." And he takes the
fundamental concepts and laws of those theories to be the a priori
laws that constitute experience's possibility. Why?



For Cohen, these distinctive views are consequences of his
interpretation of Kant's philosophical method. Cohen and his
students, Paul Natorp and Ernst Cassirer, would take this
philosophical method to be the defining characteristic of
Cohen's Kantianism, rather than any of Kant's particular
arguments or doctrines (Cassirer 2005 [1912], 115; Natorp 1912,
194-5). As Cohen himself puts it, "[p]hilosophy is not
'doctrine', but critique" (Cohen 1885, 577), and it
is above all the Kantian philosophical method that distinguishes
Cohen's philosophy from pre-critical philosophy.



We can see Cohen's view of philosophical method in its nascent
form emerge from his interpretation of Kant's Analytic of
Principles and the *Prolegomena to Any Future Metaphysics*.
However, Cohen would articulate the method clearly only much later, in
his mature writing. Only later would Cohen (and his students) call it
the "transcendental method." (See Luft 2015, Ch. 1.5 for a
thorough discussion of the transcendental method.)



According to Cohen, for Kant mathematical natural science is the
starting-point of philosophical investigation. It is the explanandum
that Kantian philosophy seeks to explain. It is then up to philosophy
to identify and articulate the a priori laws in that experience that
are responsible for making it objective. If it is less than obvious
that this is Kant's method in the *Critique of Pure
Reason*, Cohen insists, it is at least clear in the
*Prolegomena*. There, Kant is explicit that he begins by
assuming that mathematical natural science provides us with genuine
objective knowledge, and that it contains synthetic a priori
principles; Kant is likewise explicit that his task is to identify the
necessary conditions of those principles' possibility, and that
doing so will explain the objectivity of mathematical natural science.
(Kant is also explicit that this method, which in the
*Prolegomena* he calls the 'analytic method,' is
not the method he uses in the *Critique of Pure Reason*, nor
would it be suitable for the full project of the *Critique*.
Cohen seems cheerfully undaunted by this textual anomaly.) (See Rendl
2018 for discussion of Cohen's motivations for taking the
analytic method of the *Prolegomena* as his guide.) 



Taking Kant's method in the *Prolegomena* as his guide,
Cohen claims that the method of Kantian philosophy is this. He thinks
philosophy takes the theories of mathematical natural science as its
starting point. It begins, as he puts it, with the "fact of
mathematical natural science" (Cohen 1883, 119-120).
Although Cohen does not emphasize it in the first edition of
*Kant's Theory of Experience*, he thinks (and it is
consistent with his views) that this "fact of science"
changes as science progresses. On the transcendental method, the
philosopher takes the best physical theories of the day as her
starting point, and thus the "fact of science" will be
different for philosophers in different periods of the history of
science.



Further, Cohen identifies the a priori of his third level, the laws of
mathematical natural science, with the synthetic a priori principles
Kant thinks mathematical natural science contains. Cohen says of these
synthetic a priori principles that they are "that which is
present" in experience (Cohen 1987 [1871b], 206). So philosophy
seeks to explain the possibility of experience by identifying and
articulating the a priori laws "present" in it. As Cohen
would later put it, experience, conceived as the evolving doctrines of
mathematical natural science, is "given as a task"
[*aufgegeben*] to philosophy: while experience is given with
synthetic a priori principles already contained in it, it is the task
of philosophy to identify and articulate those principles, and in so
doing to explain how they make objective experience possible.



It can be difficult to see how this method allows for any
philosophically critical evaluation of theories in the history of
science - a kind of evaluation Cohen never shies away from. On
the transcendental method, philosophy does not seek philosophical
grounds for casting doubt on or rejecting mathematical or scientific
theories. Rather, it starts by taking those theories and their
objectivity for granted. It starts with them as *facts*, as
explananda in need of philosophical explanation. But Cohen often
criticizes and rejects theories he does not like, and does so for
apparently philosophical reasons. This is especially clear in the
historical sections of his 1883 *Principle of the Infinitesimal
Method and its History*, where Cohen uses apparently philosophical
principles to criticize and reject various efforts in the history of
mathematics to define, for example, limits and infinitesimals. But
Cohen's criticisms do not violate the transcendental method. The
principles that serve as the basis for his criticisms emerge from a
philosophical investigation of theories given in the history of
science. They are thus principles that turn out to be required for the
philosophical explanation of those theories and their objectivity.



Cohen's colleague at Marburg, Natorp, would emphasize a major
advantage of the transcendental method for Cohen (Natorp 1912,
196-7). This method allows Cohen to avoid what he and his
students took to be the two major errors of other post-Kantian
philosophy. First, because Cohen sought to explain the possibility of
experience by appeal to a priori laws in it, he avoided the
physiologically-oriented psychologism of Helmholtz and Lange, among
others. But second, the transcendental method anchors Kantian
philosophy to mathematical natural science as its starting point. This
anchor prevents philosophy from taking off on the speculative,
metaphysical flights of fancy that, in the minds of many Kantian
philosophers in the 1860s and 1870s, decisively undermined the
Idealist *Naturphilosophie* of the first half of the nineteenth
century. For Cohen and his students, the transcendental method thus
makes possible a philosophy that is properly scientific, without
absorbing it completely into physiology and psychology.


## 4. A Period of Transition



Cohen's 1883 *The Principle of the Infinitesimal Method and
its History* and the second, 1885 edition of *Kant's
Theory of Experience* reveal the considerable extent to which he
modified and deepened his epistemology and philosophy of science over
the course of the 1870s and early 1880s. In one move that marks his
increasing clarity about his own views, he abandons the term
"theory of knowledge" [*Erkenntnistheorie*] as
irredeemably psychologistic, since it was too closely associated with
psychologically-oriented projects such as Helmholtz's. Instead,
he proposes to call the project of his theoretical philosophy
"critique of knowledge" [*Erkenntniskritik*].



Beyond merely terminological changes, in *The Principle of the
Infinitesimal Method* and the second edition of *Kant's
Theory of Experience*, Cohen offers a better developed and more
clearly articulated account of the substance of his epistemological
view. He calls the view "critical idealism." The view is a
form of idealism, because Cohen still maintains that a priori laws
contained within scientific theories make it possible for those
theories to represent objects. But the idealism is
"critical" because it is Kantian - that is, for
Cohen, because it is committed above all to the transcendental method
(Cohen 1883, 6ff).



Cohen's increased clarity about critical idealism emerged in
part from work on the history of philosophy he did in the 1870s and
early 1880s. He presents his view of that history in both *The
Principle of the Infinitesimal Method* and a long introduction he
added to the second edition of *Kant's Theory of
Experience*. As Cohen sees it, Plato and Leibniz play roles in the
development of critical idealism that are second only to Kant's.
Like Kant, both sought to understand mathematics as paradigms of
knowledge in general. Further, as Cohen argued in his 1878 essay
"Plato's Doctrine of Ideas and Mathematics," Plato
anticipated Kant in maintaining that the objects of our thought are
explained by appeal to "ideas" (which Cohen, employing his
characteristic form of philosophical charity, identified with Kantian
a priori laws) (Edel 1988, Ch. 4). In contrast with this
Platonic-rationalist antecedent to critical idealism, Cohen argues,
stands an Aristotelian-empiricist tradition. Members of this
uncritical tradition believe, in one way or another, that we must
explain the objects of our thought by appeal to objects that exist
independently of the mind.



At the same time, Cohen's willingness to reject certain Kantian
doctrines reveals the extent to which his critical idealism was a
commitment only to what he took to be Kant's philosophical
method. For example, in one of the many sections he added to the
second edition of *Kant's Theory of Experience*, Cohen
argues that the proper way to understand the notion of the
thing-in-itself is not (as Kant seems to suggest) as an object that
exists independently of the subject's representations, somehow
affecting the subject and thereby giving rise to her sensations.
Rather, Cohen argues that we must think of the thing-in-itself as the
totality of all experience, taken as an object of thought (Cohen 1885,
503ff). Since it is the totality of all experience, rather than merely
the experience we happen to have at our particular point in the
history of science, the thing-in-itself is the ideal that science and
critical philosophy aim at (see Stang 2018).



*The Principle of the Infinitesimal Method* is perhaps most
significant for how it presents a detailed illustration of what the
critique of knowledge done according to the transcendental method
looks like. The book is a philosophically critical history of the
development of calculus. In it, Cohen aims to establish the validity
of calculus' foundational concepts - concepts such as
*limit* and *infinitesimal* - in the face of
philosophical objections against them. He also aims to establish a
connection between the concept of infinitesimals and natural
science's capacity to represent reality. In fact, these two aims
are connected. For Cohen, the concept of an infinitesimal magnitude is
valid for use in calculus, because it is a necessary condition of the
possibility of natural science's representation of real objects.
(See Edel 2010, Richardson 2006, Giovanelli 2011, Giovanelli 2016, and
Edgar forthcoming).



Cohen sees this connection between infinitesimals and reality in the
section of the *Critique of Pure Reason* that Kant called the
Anticipations of Perception. In the Anticipations, Kant introduces the
idea of magnitudes that can vary continuously from a finite magnitude
to zero. He calls these continuously variable magnitudes *intensive
magnitudes*. Kant argues that there is an important connection
between continuously variable magnitudes, sensation, and reality.
While Cohen thinks Kant's concern with sensation is a mistake,
he thinks the connection between continuously variable magnitudes
- that is, infinitesimals - and reality is exactly right.
The connection is this. For Cohen, mathematical natural science can
represent real objects only if it represents them as having unique
identity conditions. Those identity conditions are defined by unique
locations in space and time. But, Cohen insists, the mathematical
units that natural science uses to represent space and time must
themselves be defined by appeal to infinitesimal magnitudes.



That final claim - that the mathematical units of space and time
must be defined by appeal to infinitesimals - follows for Cohen
from the principle of continuity. This is the Leibnizian principle
that Cohen glosses as "there are no jumps in
consciousness" (Cohen 1883, SS42), which for him means that
mathematical and scientific theories must represent objects as
continuous. Recent commentators have emphasized that, for Cohen, the
principle of continuity is a requirement of reason, and thus an
expression of his methodological rationalism (see Dambock 2017,
4.4.1 and Edgar forthcoming). At the same time, that the principle of
continuity serves this function for mathematical natural science is,
for Cohen, a fact of science revealed by his historical investigation
of the development of calculus.


## 5. Pure Thinking, Generation, and Origin



However, Cohen would not remain satisfied with his account of
calculus' foundational concepts and their significance for a
philosophical theory of knowledge. His final major work in
epistemology was the 1902 *Logic of Pure Knowledge*, the first
part of his projected *System of Philosophy*. In that book,
Cohen claims that there is an important connection between the
concepts of infinitesimals and infinities, and something he now calls
"pure thinking." For Cohen, thinking is *pure* just
in case it is independent of any and all influences that are external
to thought or reason. Nothing is *given* to pure thinking
- not the data of sensible intuition, not the activity of a
Fichtean I, not the Absolute. Cohen claims that the infinitesimal
calculus is the paradigmatic example of "the triumph of pure
thinking" (Cohen 1902, 35). But more than that, he thinks an
analysis of the infinite is precisely what first raises the
philosophical question of pure thinking - that is, the question
of how pure thinking functions to let mathematical natural science
represent objects (Cohen 1902, 35).



The concept of pure thinking, and the closely related concepts of
*generation* and *origin*, are central to Cohen's
project in the *Logic*. All three concepts have to do with the
principles that, on Cohen's view, define what an object is for
mathematical natural scientific theories. In *Kant's Theory
of Experience*, Cohen had been content to identify and exhibit
synthetic a priori principles as "present" in experience.
But now in the *Logic*, he is concerned with the question of
those principles' foundation - that is, with their
"origin." Cohen now argues that pure thinking
*generates* those principles from itself. Or in his preferred
idiom, pure thinking is "generation."



On its face, the concept of pure thinking is obscure. Likewise for
Cohen's claim that pure thinking generates out of itself the
principles that explain mathematical natural science's objective
validity. However, we can start to understand these ideas by recalling
two of the commitments that underpin all of Cohen's theoretical
philosophy: first, his idealism, that is, his insistence that a priori
laws of human knowledge determine what counts as an object for us; and
second, his methodological rationalism, that is, his commitment to an
unending search for reasons and his unwillingness to accept anything
as given or brute.



For Cohen in the *Logic*, the principles that constitute the
object of mathematical natural scientific knowledge must be generated
by pure thinking, since only then can we have a priori knowledge of
that object (Beiser 2018, 196-7). But Cohen's
methodological rationalism gives us another way to understand why
those principles must be generated by pure thinking. To say that pure
thinking is independent of any influences external to thought or
reason is to say that pure thinking makes a rational demand: it can
accept no representations that are given, brute, or unexplained. When
Cohen asserts that pure thinking *generates* the principles
that constitute the object of mathematical natural science, he means
that no part of that object has its source outside of pure thinking
and thus no part of it can be left as given or unexplained. For Cohen,
then, pure thinking is not so much a species of cognitive content so
much as it is a methodological demand. (See Beiser 2018, [Ch. 11] for
a detailed account of pure thinking as *regulative*.)



One striking consequence of Cohen's conception of pure thinking
is something he is at pains to emphasize, namely, a decisive break
with Kant on a point central to Kant's system. In the
*Logic*, Cohen rejects Kant's view that (in human
knowledge) there is a faculty of sensible intuition that is
independent of the faculty of understanding. In effect, Cohen now
decisively rejects Kant's claim that sensible intuition is the
capacity that immediately relates objects to the knower (Kant
1781/1787 [1998], A19/B33). From Cohen's perspective, that view
is now unacceptable, because it posits a faculty of sensibility that
is forever external to pure thinking, and thus forever given or
unexplained. Further, since on Cohen's view a philosophical
account of knowledge does not appeal to an independent faculty of
sensible intuition, Cohen insists that the project he had previously
called the "critique of knowledge" now becomes the
"logic of pure knowledge." (Cohen's view in the
*Logic* appears somewhat similar to so-called
"conceptualist" interpretations of Kant in the
contemporary Kant literature. [For example, Longuenesse 1998, Ch. 8
and Friedman 2012.] So how radically one thinks Cohen's
*Logic* breaks with Kant will depend on one's views of
the conceptualist interpretation of Kant. I leave it as an open
question how much Cohen's views in the *Logic* differ
from the conceptualist interpretation of Kant.)



Notwithstanding that decisive break with Kant, other parts of the
*Logic* still reflect Cohen's Kantianism. For Cohen, pure
thinking generates the pure principles of knowledge through judgment
- the epistemic structure that, he thinks (following Kant),
relates different concepts to one another. Consequently, in the
*Logic* Cohen aims above all to articulate the twelve different
types of foundational judgments that, he thinks, make it possible for
mathematical natural scientific theories to represent objects. To be
sure, Cohen's twelve types of judgment partly reflect the
section of the first *Critique* that Kant called the table of
the functions of judgment. At the same time, even here Cohen does not
merely reproduce Kant's doctrine. Perhaps most significantly,
Cohen abandons Kant's account of the three possible
"qualities" of judgment and replaces it with his own
account of the judgments of origin, identity, and contradiction. For
Cohen, these judgments express the most foundational moments in the
origin of pure thinking. Moreover, he develops his accounts of them at
least partly from reflection on the concepts of the infinite,
infinitesimals, and continuity. This should hardly be surprising,
given his claim that pure thinking's function in knowledge is
first revealed by an analysis of the infinite.



Cohen never gave up the view that the concepts of the infinite,
infinitesimals, and continuity were central to a philosophical account
of pure thinking and knowledge. Yet his account of those mathematical
concepts was never convincing to mathematicians and philosophers of
mathematics in the analytic tradition. Gottlob Frege complained that
Cohen's views in the *Principle of the Infinitesimal
Method* were too unclear to be intelligible (Frege 1885 [1984]).
Bertrand Russell objected that Cohen failed to understand that
mathematicians now had a formal treatment of continuity and limits
that freed them of any commitment to infinitesimals (Russell 1903, Ch.
41). Even Cassirer, Cohen's own student, abandoned Cohen's
account of infinitesimals, likely in response to Russell's
objections. Consequently, Cassirer also abandoned many of the details
of Cohen's theory of knowledge in the *Logic*. (See
Giovanelli 2016 for an account of how even Cohen's allies were
unpersuaded by Cohen's account of the infinitesimal concept and
its centrality to his account of knowledge. Edgar forthcoming argues
that Russell in particular failed to understand the philosophical
significance of Cohen's account of the infinitesimal concept and
its place in his theory of knowledge.)


## 6. Ethics, Jurisprudence, and the Laws of Human Action



Cohen did not restrict his use of the transcendental method to
epistemology and philosophy of science. As Sebastian Luft argues,
"the exact sciences are his point of departure, but they are not
the only object of critique" (Luft 2015, 58). For Cohen, the
transcendental method must be applied to ethics as well. He thus
sought to extend its application beyond a treatment of the laws of
nature to the laws of human action. He ultimately argued that the
result of this application was a Kantian ethical justification for
democratic socialism.



Cohen's first attempt to apply the transcendental method to
ethics was his *Kant's Foundations of Ethics*, which
first appeared in 1877. In it, he is motivated by a dissatisfaction
that Kant could not provide a transcendental deduction of the moral
law the way he had for the categories in the first *Critique*
(Cohen 1877, 179). In the first *Critique*, Kant had argued
that the categories are justified, because they are necessary
conditions for the possibility of experience. But in the *Critique
of Practical Reason*, he argued that the moral law cannot be
justified as a necessary condition of experience, because we can
experience ourselves only as beings whose actions have natural causes,
and cannot experience ourselves as free moral agents. Thus, Kant
insisted, the moral law must be the sole "fact of
reason"--a fact that has no, but needs no, justification
beyond the force with which it impresses itself on us (Kant 1999
[1788], 5:31, 5:47-8). Cohen thinks this was an inadequate
justification of the moral law. He attempts to show that an improved
justification results from transcendental reflection on the idea of a
pure will, that is, the idea of a will that is not conditioned by any
antecedent causes and is therefore free. With Kant, he argues that
such a will is possible only on the condition that the moral law
applies to it. But unlike Kant, he does not assert the actuality of a
pure, free will. Rather, he argues that freedom of the will is itself
a regulative ideal, an end at which we aim our actions (Cohen 1877,
199-201ff.).



However, Cohen did not remain satisfied with this account of the
foundations of the moral law, nor with his early view of how the
transcendental method applies in the domain of ethics. In his 1904
*Ethics of Pure Will*, the second part of his *System of
Philosophy*, he offers a significantly revised account of both.
Here, Cohen's account is shaped by two commitments. First, he
asserts that the subject matter of ethics is humanity, that is, human
moral agency (Cohen 1902, 3). He thinks the aim of ethics is to
construct a normative theory of the human moral agent and its will.
Second, unlike in his earlier *Kant's Foundations of
Ethics*, Cohen now takes seriously the requirement that the
transcendental method begins with a fact of science. For Cohen, just
as epistemology and philosophy of science must begin by accepting the
theories of pure natural science as given, ethics according to the
transcendental method must begin with a science of humanity.



Cohen canvasses three possibilities for such a science of humanity.
Ethics might start with a Fichtean "science" of the
subject. But Cohen rejects this possibility as a lapse back into
pre-critical speculation (Cohen 1902, 13ff.). Alternatively, ethics
might start with naturalistic human sciences such as psychology. But,
Cohen objects, making these sciences the starting point for ethical
reflection would violate Kant's insistence that ethics
distinguishes between normative and non-normative considerations,
between what Cohen calls Being and the Ought (Cohen 1902, 9ff.).



Thus Cohen argues that ethics begins with the science of
jurisprudence, that is, the science that investigates law and human
beings considered precisely as agents whose actions are bound by
law's normative constraints (Cohen 1902, 66ff.). Cohen does not
have in mind a jurisprudence that is concerned only with positive law.
Rather, the transcendental method in ethics begins with *pure*
jurisprudence, which investigates the very concept of law and its
essential features such as universality. Pure jurisprudence is thus
the science of universal laws of human action. (Pure jurisprudence in
this sense was one topic of German legal theory around the turn of the
twentieth century. Rudolf Stammler's 1902 *The Theory of
Justice* is representative.) For Cohen, this evolving body of pure
legal doctrine constitutes a fact of science. Ethics according to the
transcendental method accepts it as given. Then, by reflecting on this
evolving body of legal doctrine, ethics seeks to construct a theory of
the human being as a moral agent (Schwarzschild 1975).



Pure jurisprudence guides ethics in constructing a theory of humanity
by overcoming a problem that, Cohen thinks, any theory of humanity
faces. He claims the concept of humanity has a tension contained in
it: a human being is at once an individual and a member of various
pluralities, such as religious communities or economic collectives
(Cohen 1902, 3ff). Further, the wills of pluralities of individuals do
not necessarily cohere: individuals do not necessarily will things
that are consistent with what other individuals will, or with what the
community as a whole wills. But, Cohen suggests, without an account of
what an individual may will consistently with the wills of others, we
have no coherent account of the moral agent as both an individual and
a member of a plurality. Thus any theory of humanity requires an
account of how to reconcile individuals' wills within a
plurality. As Cohen puts it, individuals' wills must be unified
into a totality. Or, in somewhat less opaque language, we must
understand how the universal laws of an ideal state can reconcile the
wills of individuals and pluralities (Wiedebach 1997, Pt. 3). Further,
according to Cohen, if we want to think systematically about what
those universal laws are, we must start by reflecting on the evolving
body of legal doctrine provided by pure jurisprudence--the
science of universal laws. For Cohen, the doctrines of pure
jurisprudence to do evolve arbitrarily: they evolve in an unending
process of demanding and giving reasons. Paul Nahme thus claims that
"[w]e can therefore describe Cohen's account of the
ethical will as a logic of public reasoning..."(Nahme 2019,
268).



Cohen's emphasis on the universal character of ethical laws is
clearly Kantian in spirit, and he certainly intends the universal laws
of an ideal state to be the laws people must give to themselves in
Kant's realm of ends. But still, it is not obvious how exactly
to characterize the relation of Cohen's ethics to Kant's.
On one plausible reading of Kant, a general theory of the moral will
was the basis for his theory of law in the Doctrine of Right. But on
Cohen's view of how to apply the transcendental method to
ethics, ethics begins with a theory of law from pure jurisprudence and
then, by reflecting on pure law, it seeks to construct a general
theory of the moral agent and its will. Thus Cohen's account of
the foundations of ethics might differ fundamentally from
Kant's--indeed, it might turn Kant's account on its
head.


## 7. The Kantian Foundations of Democratic Socialism, Aesthetics



However, while a doctrine of pure, universal laws makes possible a
coherent theory of the concept of humanity, Cohen thinks the laws of
any actual state will fall short of pure law's ideal form. He
maintains that states, in the course of their development through
history, tend to amend their laws so as to better approximate the
ideal laws. Cohen does not argue from some antecedent philosophical
theory of human nature that history is somehow compelled to exhibit
this progress (Cohen 1902, 37). Rather, he simply accepts it as a
datum of history: philosophy can no more deny this progress than it
can deny progress in the history of physics and mathematics. At the
same time, Cohen's optimism was tempered by an awareness of
injustice in the non-ideal world: moral progress must be unending,
precisely because no actual state will ever realize the ideal
completely (Schwarzschild 1979, 139-40). During the World War,
Cohen even came to believe that certain forms of nationalism might be
ineliminable engines of humanity's historical progress towards a
cosmopolitan confederation of ideal states. (See Vatter 2017 for
discussion of the tension between Cohen's liberal
cosmopolitanism and his wartime nationalism.) There is, in
Cohen's terms, an unbridgeable gap between Being and the
Ought.



As Cohen saw it, political progress was, and ought to be, moving
towards democratic socialism. The laws of an undemocratic state cannot
genuinely reconcile the wills of individuals and pluralities of
individuals, even if the state has the power to control their
behavior. So, Cohen argued in his 1904 essay "The General,
Equal, and Direct Right Vote," any state whose laws make the
wills of individuals and pluralities cohere must be one with universal
suffrage (van der Linden 1988, 215). He thus opposed Wilhelmine
Germany's system of tiered suffrage, under which lower-class men
from some regions voted only in national elections and women did not
vote at all.



Moreover, Cohen argued that, as states amend their laws to better
approximate ideal laws, legal frameworks should emerge to govern the
economic activity of democratically-constituted pluralities of people.
In other words, he thought that an ideal state would allow democratic
workers' collectives to own the means of production. In his
*Ethics of Pure Will* as well as his 1896
"Postscript" to F.A. Lange's *History of
Materialism*, Cohen argues that this socialism follows
straightforwardly from a proper understanding of Kant's
categorical imperative (Cohen 1902, 320). For Cohen, not treating
people merely as a means entails not exploiting their labor (Holzhey
2005, 26). Along with Lange, Cohen thus advocated a socialism with
Kantian and liberal foundations, rather than Marxist ones. (The 1890
repeal of Bismark's Anti-Socialist Laws would have offered him
some evidence that Germany was moving towards that democratic
socialist ideal.) Cohen's Kantian socialism was an important
influence on socialist political leaders such as Eduard Bernstein, a
social democratic member of the *Reichstag* (Gay 1970).



Politics was not the only sphere in which Cohen thought philosophy
must engage with culture. In the third part of his *System of
Philosophy*, the *Aesthetics of Pure Feeling* (1912), he
argued that critical philosophy could not leave art without a
philosophical foundation (Cohen 1982 [1912], 1.4). In his aesthetics,
Cohen sought to avoid Schelling and Hegel's view that art is an
expression of ideas that can be distilled from it and expressed in
purely conceptual terms. Likewise, Cohen rejected Helmholtz's
physiological approach to aesthetics, exemplified by his physiological
and experimental investigation of tone-perception in music. However,
in Cohen's theory of knowledge and ethics, he had avoided these
approaches by adhering to the transcendental method--that is, by
starting with a "fact" of (natural or juridical) science
and then articulating the a priori, universal laws that constitute
that science's object. But for Cohen, there is no "science
of art." Thus for Cohen, a philosophical aesthetics must begin
with only the "fact" that art is central to culture (Poma
1997, Ch. 7; Guyer 2008).



From this starting point, Cohen develops an account of "pure
feeling." Pure feeling cannot be the consciousness of the
objects of natural science or the moral consciousness of ethical
ideals. But these two domains of objects - the world as it is
and the world as it ought to be - are the only possible objects
we can be conscious of. Thus, Cohen argues, pure feeling must be the
consciousness *that we are conscious*. That is, it is our basic
level of consciousness of the fact that we can be conscious of both
the objects of natural science and of ethical ideals (Guyer 2008).
Further, Cohen characterizes that basic level of consciousness as
"lawfulness" (*Gesetzlichkeit*) (Cohen 1982 [1912],
1.68ff; cf. de Launay 2005). According to Cohen, this lawfulness of
pure feeling is what produces the object of aesthetic judgment.
(Trochimska-Kubacka 2018 provides a useful survey of how Cohen's
mature aesthetics differs from Kant's.)



Apart from systematic philosophical considerations, Cohen's
aesthetics is of interest for the light it promises to shed on his
philosophy of religion. Cohen came to believe that concepts central to
philosophy of religion should be articulated by interpreting
historical scriptural texts, including prayers and biblical poetry and
prose (Kepnes 2007, Ch. 2) (see SS9 below). Thus recent
commentators have used Cohen's account of lyric poetry in the
*Aesthetics of Pure Feeling* to help make sense of his account
of an individual's love for God (Poma 2000), as well as his
conception of compassion (Wiedebach 2002).


## 8. Philosophy of Religion and the Correlation between the Individual and God



Cohen retired from Marburg in 1912, in order to teach at the Academy
of Jewish Sciences, a rabbinical seminary in Berlin, where he remained
until his death. In 1908 he had written his *Ethics of
Maimonides*, and after 1912 he worked above all else on religious
philosophy, writing *The Concept of Religion in the System of
Philosophy* (1915) and his monumental *Religion of Reason Out
of the Sources of Judaism*, which appeared in 1919, after his
death. The *Religion's* significance is difficult to
overstate: it has been called "the single most consequential
work of Judaic thought in the period of the nineteenth and twentieth
centuries" (Dietrich 2000). In it, Cohen articulates a
conception of a "religion of reason," and argues that
fundamental concepts of Judaism, as they are revealed in historical
Jewish texts, were the original sources of that religion of
reason.



Cohen initially faces a problem in defining the relation of religion
to systematic philosophy (Holzhey 2000). In both the *Concept of
Religion* and the *Religion of Reason*, he identifies the
two central concepts of religion as humanity and God (Cohen 1972
[1919], 11ff.) But he had already offered philosophical accounts of
those concepts in his ethics. For Cohen, ethics is the theory
precisely of humanity. But also, in his *Ethics of Pure Will*,
Cohen defined God as the conjunction of two ideas: the concept of
ideal ethical laws unifying all humanity into a harmonious realm of
ends, and the faith that, at the end of history, this ideal would be
realized. Thus Cohen's ethics seem to offer complete, systematic
accounts of both of religion's central concepts. Consequently,
Cohen appears to face a dilemma: religion has a distinctive role to
play in philosophy just in case his philosophical ethics offered only
incomplete accounts of humanity and God. But this is unacceptable to
Cohen.



Cohen must thus offer an account of the distinctiveness of religion in
relation to systematic philosophy, and do so in a way that does not
entail the incompleteness of his ethics. The crux of his account of
religion's distinctiveness seems to be the vaguely Tolstoyan
assumption that insofar as individuals are moral, they are alike, but
that every individual is immoral in his or her own way. In the
*Religion*, Cohen claims that systematic philosophical ethics
is concerned with individuals only insofar as they are members of
pluralities or humanity as a whole--that is, only insofar as they
are bound by ethical laws. But this is not the only way to conceive of
individuals. We can also recognize an individual's particular
moral failings, and we can recognize the particular ways an individual
suffers because of those failings (Zank 2000). When we recognize an
individual this way, Cohen says (appropriating Feuerbach's
vocabulary) we recognize the individual as a "Thou,"
rather than merely as a "He," a generic representative of
humanity. On Cohen's account, it thus turns out that systematic
philosophical ethics does not address certain pervasive features of
our lived moral experience: our varied, multiple, and particular moral
failings, as well the suffering they bring us (Bonaunet 2005, 49ff.).
This is not, he thinks, a criticism of ethics for being incomplete. It
is only the recognition of what ethics is, and is not, concerned
with.



Religion, however, is concerned precisely with the individual's
particular moral failings (Zank 1996 and 2000). While we can recognize
another individual as a "Thou," and so assess her
particular moral failings, Cohen thinks the most important person to
recognize as a "Thou" is ourselves. As he puts it, we
discover the "I" only by means of the "Thou."
That is, we recognize our moral selves by recognizing our own
particular moral failings. As he puts it, "[i]n myself, I have
to study sin, and through sin I must learn to know myself"
(Cohen 1972 [1919], 22). Without first discovering our own particular
moral failings, we could not strive for moral improvement. But for
Cohen, this process of moral improvement is inherently religious.
Prayer gives us the strength to overcome our hypocrisy and
self-deceit. And only when we do that can we confess, that is,
acknowledge our own moral failings. This in turn makes it possible for
us to atone, that is, to strive to realize our ethical ideals in ways
that respond appropriately to our particular failings (Horwitz 2000;
Zank 2000). Thus, for Cohen, knowledge of our own moral selves is the
"deepest ground" of religion: "[t]he discovery of
humanity through sin is the source from which every religious
development flows" (Cohen 1972 [1919], 20).



By striving for moral improvement, the individual relates herself to
her ethical ideals. But since for Cohen our concept of ideal ethical
laws just is our idea of God (or at least a component of our idea of
God), an individual's striving for moral improvement relates her
to God. In Cohen's terms, striving for moral improvement
establishes a "correlation" between the individual and
God. This correlation is a profoundly personal relationship: since the
individual confesses and atones for her own particular sins, she
relates herself to God in a way that is similarly particular to her.
In relating herself to God, Cohen thinks, the individual thereby
constitutes herself as a unique moral and religious self, and God
becomes her "guide on the long road from sin to virtue"
(Cohen 1919, 20).



Thus Cohen maintains that there is a distinctive role in philosophy
for a religion of reason: its distinctive concern is precisely with
the particularities of individual humans' lived moral
experience, and their attempts to overcome their various and different
moral failings as they strive to realize ideal ethical laws.



Nevertheless, almost since before Cohen's ink was dry, there
have been significant disagreements about the proper interpretation of
Cohen's account of the relation between religion and his
systematic philosophy, and of his account of the individual's
relation to God.



An early and enormously influential reaction to Cohen's view was
his friend Franz Rosenzweig's. Rosenzweig argued that
Cohen's concern in the *Religion* with the concrete
individual, expressed in the idea of the individual's
"correlation" with God, constituted a decisive break from
the *Ethics of Pure Will*'s concern with universal laws
of human action (Rosenzweig 1924). On Rosenzweig's
interpretation, in the *Religion* Cohen abandons the
rationalism that characterizes his earlier conception of humanity
working out its relation to God in a historical process of improving
the laws by which it governs itself. Instead, Rosenzweig suggests,
Cohen commits himself to a conception of the religious individual that
is more fundamental than universal, rational ethical considerations.
Thus for Rosenzweig, despite Cohen's claims to the contrary, his
views in the *Religion* are fundamentally discontinuous with
his views in his systematic ethics.



More recently, Robert Erlewine (2010) has offered a different account
of how Cohen's *Religion* might break decisively with his
systematic ethics. Cohen's ethics are concerned with how
pluralities of different wills are unified into law-governed
totalities (cf SS6 above). In his *Ethics of Pure Will,*
Cohen argues that different wills are so unified in the ideal state.
But, Erlewine argues, Cohen defends a different view in his *Ethics
of Maimonides* and his *Religion*. For Cohen in those
works, on Erlewine's account, different wills are unified in the
law-governed community of the religious, and specifically Jewish,
congregation.



In contrast, others have defended the consistency of Cohen's
views, arguing that the *Religion* completes the systematic
ethical project he had started in his *Ethics of Pure Will*.
Cohen's ethics is concerned with the constitution of the will,
that is, the moral self. But this moral self is an ideal, and thus it
is only in the *Religion* that Cohen takes up the question of
the human self as a concrete individual. Consequently, Schwarzschild
(1975) argues that Cohen's account of the concrete individual in
the *Religion* completes the theory of moral selfhood begun in
the *Ethics of Pure Will*. Alternatively, Poma (1988) argues
that the religious idea of God, since it is the idea not only of
universal ethical ideals, but of humanity's progress towards
those ideals, provides a connection between the descriptive and
normative aspects of Cohen's philosophy.



However, if Cohen's philosophy of religion *completes*
the project of his systematic ethics, it is difficult to see how to
avoid the implication that Cohen's systematic ethics were,
considered on their own, incomplete - a claim Cohen himself was
at pains to deny.



The debate about these two broad interpretive strategies has, at
times, taken on the significance of a debate about how best to view
Cohen an an intellectual. That is, the debate is not simply about
whether to prefer an interpretation emphasizing a sharp discontinuity
between Cohen's views in the *Religion* and his earlier
views, or an interpretation emphasizing continuity in his views.
Rather, as Daniel Weiss points out, the debate has sometimes been
about whether to understand Cohen first and foremost as a Jewish
thinker or primarily as a neo-Kantian philosopher (Weiss 2012,
5ff).



However, a third interpretive strategy seeks to avoid this dichotomy,
by avoiding both the claim that Cohen's *Religion* is a
decisive "break" with his systematic ethics and the claim
that his religion "completes" those ethics. Michael Zank
(1996 and especially 2000) has emphasized that Cohen did not intend
his philosophy of religion to be part of the *System of
Philosophy*, but nor can the philosophy of religion be in any
sense a "break" from the *Ethics of Pure Will* in
his *System*, since he started working on both projects at
roughly the same time around the turn of the century. Cohen's
systematic philosophy and his philosophy of religion thus stand as
complements to each other: whereas one conceives the human as an ideal
agent constituted by universal ethical laws, the other treats the
human as a concrete individual, constituted by the particularities of
his own moral failings and attempts to atone for them. Similarly,
Weiss (2012) argues that the religious and ethical conception of the
individual are different "voices" in Cohen that cannot be
reduced to a simple, theoretical unity (in the *System of
Philosophy*), but that both voices are necessary.


## 9. Monotheism and Prophetic Messianism



Cohen's second aim in the *Religion* is to show that
Judaism has what he calls a special "methodological"
significance for philosophy of religion, because it is the original
historical source of a religion of reason (Cohen 1972 [1919], 8).
Judaism has this special status because it was, Cohen contends, the
original monotheistic religion, and only monotheistic religions can be
religions of reason. The polytheism of the ancient world posited
different gods for different peoples in different places. But, Cohen
argues, since reason is a "universal human power" that
belongs to all humanity (Cohen 1972 [1919], 7-8), a religion of
reason cannot recognize different gods for different people, but must
recognize a single, unique God for all humanity. Since the idea of
such a God first emerged in history with Judaism, it is the original
source of a religion of reason. Consequently, the investigation of a
religion of reason must recover that religion's source by
interpreting the historical scriptures and liturgical practices of
Judaism (Kepnes 2007, Ch. 2).



According to Cohen, monotheism, and so too Judaism, was the historical
source of the idea that all humanity could be unified by a single set
of ethical laws. As Cohen sees it, God is the set of ideal ethical
laws. To assert that there is only one God for all of humanity is thus
to assert a universal ethical ideal, one on which individuals see all
people as "fellow humans," and not as "others"
who can be excluded from the moral community (Cohen 1972 [1919],
14ff). Later religion scholars such as Wendell Dietrich would call
this doctrine "ethical monotheism" (Cf. Dietrich 1986 and
Theodore and Hadley 2001). Cohen thinks that because monotheism has an
ethical dimension, it culminates in--its highest form is--a
view he calls prophetic messianism. For Cohen, messianism just is
"the dominion of the good on earth." It is the view that
the Messiah's coming consists in nothing but the ultimate end of
injustice (Cohen 1972 [1919], 21). Prophetic messianism is thus an
expression of faith that humanity is making progress towards realizing
ideal ethical laws.



Cohen's conception of the essentially ethical nature of Judaism
had important consequences for his view of Judaism's relation to
other religions, as well as his views of Zionism and the Jews'
place in Wilhelmine Germany. Because Cohen thought the ethical nature
of Judaism was expressed by its monotheism, he believed that at least
some forms of Christianity had the same ethical nature. While for
Cohen Judaism was the original religion of reason, liberal
Protestantism expresses universal ethical ideals and is a religion of
reason as well. (He thought Catholicism failed to express properly
universal ideals. He seems not to have considered Islam.) At the same
time, because for Cohen Judaism ultimately aims at an ethical ideal
that includes all humanity, he rejected the nationalism he saw in
non-liberal forms of Judaism and was a vocal critic of Zionism. In a
public exchange with Martin Buber, Cohen argued that Jews had an
obligation to remain in their countries of birth, so that their
religious communities could serve as exemplars for the rest of
humanity of communities unified by ethical laws. He died in 1918,
before the increasing virulence of antisemitism in Germany could make
him reconsider this argument.


## 10. Cohen's Influence



The range of Cohen's influence is wide. Few figures are as
important for Jewish ethics and philosophy of religion in the
twentieth century, and in the last four decades religion scholars
have devoted considerable attention to understanding Cohen's
significance as a religious thinker and public intellectual. More
recently, historians of philosophy in the analytic tradition have
begun to appreciate the importance of Cohen's neo-Kantianism as
a source not only of influential interpretations of Kant, but of the
topics and methods characteristic of philosophy of science in the
twentieth century.



In Jewish religious thought, Cohen's influence is highly
visible, and substantive doctrines he developed in the *Ethics of
Pure Will* and the *Religion of Reason Out of the Sources of
Judaism* are still topics of debate. Martin Buber's 1923
*I and Thou* was explicitly indebted to, and a response to,
Cohen's *Religion*. Inspired by Cohen (see SS8
above), Buber elaborated an account of a relationship between the
"I" and the "Thou." Like Cohen, for Buber this
relation is the central part of how an individual establishes a
profoundly personal relationship with God. Also like Cohen, Buber
thinks establishing that relationship with God is essential to
strengthening the ethical bonds in one's community. But unlike
Cohen, Buber thought the I-Thou relationship was essentially beyond
language's ability to express--a view strikingly at odds
with Cohen's rationalist philosophical tendencies.



More recently, religious ethicists have been interested in
Cohen's view that monotheism expresses a universalist morality,
and that it expressed for the first time in history the idea that all
humanity must be subject to the same ethical laws. The religion
scholar Wendell Dietrich (Dietrich 1986) identifies this view as
"ethical monotheism," and sees Cohen as the first in a
trajectory of religious philosophers who argue that the concept of a
unique God is necessary for--or whose essential content is
revealed to us as (Gibbs 2001)--ethical laws and the freedom to
live according to them. Avi Bernstein-Nahar (1998 and 2006) argues
that Cohen's ethics, and perhaps his ethical monotheism in
particular, provide the intellectual basis for a Jewish identity that
can be shared by various Jewish communities that might otherwise have
little in common. On this view, Cohen's ethics thus have a
central role to play in Jewish education.



Cohen's influence on Anglo-American analytic philosophy is less
visible. Perhaps the only area of Anglo-American philosophy where a
substantive doctrine of Cohen's is still respected is Kant
interpretation. Before Cohen's *Kant's Theory of
Experience*, interpretations of Kant were
overwhelmingly--some have claimed
exclusively--psychologistic in one way or another (see SS2
above). Some of those interpretations attributed to Kant a form of
idealistic transcendental psychology, what Hegel called
"subjective idealism." Others attributed to Kant some form
of empirical psychologism. But Cohen denies that Kant is interested in
how the mind--either the transcendental mind or the empirical
mind--operates to synthesize the knower's representations.
For Cohen, Kant is interested in knowledge considered as if laid out
"in printed books" (Cohen 1877, 27).



Cohen is thus at the head of a tradition of anti-psychologistic
interpretations of Kant that includes Kant scholars such as Peter
Strawson and, more recently, Henry Allison. It would overstate
Cohen's influence to suggest that he directly inspired, say,
Strawson's interpretation of Kant. But the anti-psychologistic
philosophical environment in which Strawson produced his Kant
interpretation owed a great deal to Cohen's influence. (Cf. Edel
1993 for a discussion of Cohen's anti-psychologism in relation
to the tradition of analytic philosophy to which Strawson belongs.)
Further, as English-language Kant interpretation became more
sophisticated over the second half of the twentieth century and
engaged more seriously with existing German literature, historians of
philosophy like Allison found themselves at home in a much longer
German tradition of anti-psychologistic Kant interpretation going back
directly to Cohen. That anti-psychologistic tradition dominated
Anglo-American Kant interpretation for the latter decades of the
twentieth century and is still the majority view today.



However, it would be a mistake to limit a survey of Cohen's
influence on contemporary analytic philosophy to the doctrines of his
that are still alive today. Arguably his most profound influence on
analytic philosophy has not been to give us particular philosophical
doctrines, but to contribute to the basic shape, the basic orientation
of an entire major subdiscipline of philosophy. Nowhere is this more
evident than in history and philosophy of science (cf. Patton
2005).



Recent history of philosophy of science has become increasingly aware
of neo-Kantianism's influence on philosophy of science in the
twentieth century. It is thus worth taking seriously Cohen's
role in shaping twentieth-century philosophy of science. His
commitment to the transcendental method lead him to a view of
epistemology, and theoretical philosophy more generally, as
essentially a philosophically critical account of the historical
development of concepts in the mathematically-precise natural
sciences. This view of a historically-oriented philosophy of science
is nowhere more clear in Cohen's work than in his *Principle
of the Infinitesimal Method*. There are two significant points
about the view he expresses there. First, for Cohen, the theory of
knowledge begins by accepting a body of existing science, and then
gives a philosophical reconstruction of important concepts and
developments in that science's history. Second, Cohen thinks the
principal topic of the theory of knowledge is mathematically-precise
natural science--paradigmatically mathematics and physics.
Cohen's disciple, Ernst Cassirer, would carry out this program
in, among other writings, three books on the history and philosophy of
physics.



But philosophers far beyond the Marburg School were influenced by
Cohen's insistence that the philosophical reconstruction of
scientific theories is the principal method of the theory of
knowledge, and that its principal topic is mathematically-precise
natural science. Logical positivist philosophy of science took up
aspects of Cohen's project, including its central concern with
mathematics and physics. Like Cohen, positivists also thought
philosophy should accept existing bodies of science as a starting
point, and should seek to reconstruct that science's theories
and methods, even though they thought modern logic was the proper tool
for carrying out their reconstructions. (Cf. Richardson 2006 and
Ferrari 2018 for discussions of Cohen's philosophy in relation
to logical empiricism.) Recent scholarship on logical positivism, and
especially on Rudolf Carnap, has emphasized its intellectual debts to
Marburg School neo-Kantianism. (Cf. Friedman 1999 and 2000; Richardson
1998 and especially 2006.) Conversely, a French tradition of
philosophy of science emphasized a different aspect of Cohen's
project. The neo-Kantian Emile Meyerson, and his intellectual heirs,
Alexandre Koyre and ultimately Thomas Kuhn, emphasized a more
deeply historical reconstruction of scientific theories and methods.
Finally, more recent philosophy of science has seen a turn back to
views even more explicitly inspired by Marburg School doctrines: most
prominently, Michael Friedman has defended the view that in
reconstructing scientific theories, philosophy should seek to
articulate the "constitutively a priori" principles in
those theories--that is, principles that are constitutive of the
possibility of experience in precisely Cohen's sense (Friedman
2001; cf. Giovanelli 2018). More generally, although twentieth-century
history and philosophy of science did not always take seriously
Cohen's substantive doctrines, it was nevertheless affected
profoundly by his vision of philosophy as the reconstruction of
historical developments in mathematically-precise natural science.