## 1. Appearances and Things in Themselves



In the first edition (A) of the *Critique of Pure Reason*,
published in 1781, Kant argues for a surprising set of claims about
space, time, and objects:


* Space and time are merely the forms of our sensible intuition of
objects. They are not beings that exist independently of our intuition
(things in themselves), nor are they properties of, nor relations
among, such beings. (A26, A33)
* The objects we intuit in space and time are appearances, not
objects that exist independently of our intuition (things in
themselves). This is also true of the mental states we intuit in
introspection; in "inner sense" (introspective awareness
of my inner states) I intuit only how I appear to myself, not how I am
"in myself". (A37-8, A42)
* We can only cognize objects that we can, in principle, intuit.
Consequently, we can only cognize objects in space and time,
appearances. We cannot cognize things in themselves. (A239)
* Nonetheless, we can think about things in themselves using the
categories (A254).
* Things in themselves affect us, activating our sensible faculty
(A190,
 A387).[1]



In the "Fourth Paralogism" Kant defines
"transcendental idealism":



> 
> 
> I understand by the **transcendental idealism** of all
> appearances [*Erscheinungen*] the doctrine that they are all
> together to be regarded as mere representations and not as things in
> themselves [*nicht als Dinge an sich selbst ansehen*], and
> accordingly that space and time are only sensible forms of our
> intuition, but not determinations given for themselves or conditions
> of objects as things in themselves [*als Dinge an sich
> selbst*]. (A369; the *Critique* is quoted from the Guyer
> & Wood translation (1998))
> 
> 
> 



Ever since 1781, the meaning and significance of Kant's
"transcendental idealism" has been a subject of
controversy. Kant's doctrines raise numerous interpretive
questions, which cluster around three sets of issues:



(a)
*The nature of appearances.* Are they (as Kant sometimes
suggests) identical to representations, i.e., states of our minds? If
so, does Kant follow Berkeley in equating bodies (objects in space)
with ideas (representations)? If not, what are they, and what relation
do they have to our representations of them?
(b)
*The nature of things in themselves*. What can we say
positively about them? What does it mean that they are not in space
and time? How is this claim compatible with the doctrine that we
cannot know anything about them? How is the claim that they affect us
compatible with that doctrine? Is Kant committed to the
*existence* of things in themselves, or is the concept of a
"thing in itself" merely the concept of a way objects
might be (for all we know)?
(c)
*The relation of things in themselves to appearances*. Is
the appearance/thing in itself distinction an ontological one between
two different kinds of objects? If not, is it a distinction between
two aspects of one and the same kind of object? Or perhaps an
adverbial distinction between two different ways of considering the
same objects?


Sections 2-6 examine various influential interpretations of
transcendental idealism, focusing on their consequences for
(a)-(c). Section 7 is devoted more narrowly to the nature of
things in themselves, topic (b), and the related Kantian notions:
*noumena*, and the transcendental object. The primary focus
will be the *Critique of Pure Reason* itself; while
transcendental idealism, arguably, plays an equally crucial role in
the other *Critiques*, discussing them would take us too far
afield into Kant's ethics, aesthetics, and
 teleology.[2]
 While transcendental idealism is a view both about space *and*
time, and thus of objects of outer sense as well as inner sense (my
own mental states), this entry will focus on Kant's views about
space and outer objects. Kant's transcendental idealist theory
of time is too intimately tied up with his theory of the self, and the
argument of the transcendental deduction, to discuss here (see
Falkenstein 1991; Van Cleve 1999: 52-61; and Dunlop 2009 for
more on Kant's theory of time).



Before discussing the details of different interpretations, though, it
will be helpful if readers have an overview of some relevant texts and
some sense of their *prima facie* meaning. The interpretation
of these texts offered in this section is provisional; later, we will
see powerful reasons to question whether it is correct. Since some
scholars claim there is a change in Kant's doctrine from the A
edition of 1781 to the B edition of 1787, we will begin by restricting
attention to the A edition.
 Section 2.4
 discusses what relevance the changes made in the B edition have for
the interpretation of transcendental idealism. However, following
standard scholarly practice, for passages present in both editions,
the A page number followed by the B page number is given (e.g.,
A575/B603). Works other than the *Critique* are cited by volume
in the "Academy" edition of Kant's work (Ak.),
followed by the page number. At the end of this article can be found a
guide to all the editions and translations of Kant used in its
preparation.


### 1.1 Transcendental Realism and Empirical Idealism



One promising place to begin understanding transcendental idealism is
to look at the other philosophical positions from which Kant
distinguishes it. In the "Fourth Paralogism", he
distinguishes transcendental idealism from transcendental realism:



> 
> 
> To this [transcendental] idealism is opposed transcendental realism,
> which regards space and time as something given in themselves
> (independent of our sensibility). The transcendental realist therefore
> represents outer appearances (if their reality is conceded) as things
> in themselves [*Dinge an sich selbst*], which would exist
> independently of us and our sensibility and thus would also be outside
> us according to pure concepts of the understanding. (A369)
> 
> 
> 



Transcendental realism, according to this passage, is the view that
objects in space and time exist independently of our experience of
them, while transcendental idealism denies this. This point is
reiterated later in the *Critique* when Kant writes:



> 
> 
> We have sufficiently proved in the Transcendental Aesthetic that
> everything intuited in space or in time, hence all objects of an
> experience possible for us, are nothing but appearances, i.e., mere
> representations, which, as they are represented, as extended beings or
> series of alterations, have outside our thoughts no existence grounded
> in itself. This doctrine I call **transcendental idealism.** The realist, in the transcendental signification, makes
> these modifications of our sensibility into things subsisting in
> themselves, and hence makes mere **representations** into
> things in themselves [*Sachen an sich selbst*].
>  (A491/B519)[3]
> 
> 
> 



Appearances exist at least partly in virtue of our experience of them,
while the existence of things in themselves is not grounded in our
experience at all (cf. A369, A492/B521, A493/B522). Kant calls
transcendental realism the "common prejudice" (A740/B768)
and describes it as a "common but fallacious
presupposition" (A536/B564; cf. Allison 2004: 22).
Transcendental realism is the commonsense pre-theoretic view that
objects in space and time are "things in themselves",
which Kant, of course, denies.



Kant also distinguishes transcendental idealism from another position
he calls "empirical idealism":



> 
> 
> One would also do us an injustice if one tried to ascribe to us that
> long-decried empirical idealism that, while assuming the proper
> reality of space, denies the existence of extended beings in it, or at
> least finds this existence doubtful, and so in this respect admits no
> satisfactorily provable distinction between dream and truth. As to the
> appearances of inner sense in time, it finds no difficulty in them as
> real things, indeed, it even asserts that this inner experience and it
> alone gives sufficient proof of the real existence of their object (in
> itself) along with all this time-determination. (A491/B519)
> 
> 
> 



Empirical idealism, as Kant here characterizes it, is the view that
all we know immediately (non-inferentially) is the existence of our
own minds and our temporally ordered mental states, while we can only
infer the existence of objects "outside" us in space.
Since the inference from a known effect to an unknown cause is always
uncertain, the empirical idealist concludes we cannot know that
objects exist outside us in space. Kant typically distinguishes two
varieties of empirical idealism: dogmatic idealism, which claims that
objects in space do not exist, and problematic idealism, which claims
that objects in space may exist, but we cannot know whether they do
(see A377). Although he is never mentioned by name in the A Edition,
Berkeley seems to be Kant's paradigm dogmatic idealist, while
Descartes is named as the paradigm problematic
 idealist.[4]



Transcendental idealism is a form of empirical realism because it
entails that we have immediate (non-inferential) and certain knowledge
of the existence of objects in space merely through
self-consciousness:



> 
> 
> [...] external objects (bodies) are merely appearances, hence
> also nothing other than a species of my representations, whose objects
> are something only through these representations, but are nothing
> separated from them. Thus external things exist as well as my self,
> and indeed both exist on the immediate testimony of my
> self-consciousness, only with this difference: the representation of
> my Self, as the thinking subject is related merely to inner sense, but
> the representations that designate extended beings are also related to
> outer sense. I am no more necessitated to draw inferences in respect
> of the reality of external objects than I am in regard to the reality
> of my inner sense (my thoughts), for in both cases they are nothing
> but representations, the immediate perception (consciousness) of which
> is at the same time a sufficient proof of their reality.
> (A370-1)
> 
> 
> 



Merely through self-conscious introspection I can know that I have
representations with certain contents and since appearances are
"nothing other than a species of my representations" this
constitutes immediate and certain knowledge of the existence of
objects in space.



Understanding transcendental idealism requires understanding the
precise sense in which things in themselves are, and appearances are
not, "external to" or "independent" of the
mind and Kant draws a helpful distinction between two senses in which
objects can be "outside me":



> 
> 
> But since the expression **outside us** carries with it
> an unavoidable ambiguity, since it sometimes signifies something that,
> as a thing in itself [*Ding an sich selbst*], exists distinct
> from us and sometimes merely that belongs to outer appearance, then in
> order to escape uncertainty and use this concept in the latter
> significance--in which it is taken in the proper psychological
> question about the reality of our outer intuition--we will
> distinguish **empirically external** objects from those
> that might be called "external" in the transcendental
> sense, by directly calling them "things that are to be
> encountered in space". (A373)
> 
> 
> 



In the transcendental sense, an object is "outside me"
when its existence does not depend (even partly) on my representations
of it. The empirical sense of "outside me" depends upon
the distinction between outer and inner sense. Inner sense is the
sensible intuition of my inner states (which are themselves
appearances); time is the form of inner sense, meaning that all the
states we intuit in inner sense are temporally ordered. Outer sense is
the sensible intuition of objects that are not my inner states; space
is the form of outer sense. In the empirical sense,
"outer" simply refers to objects of outer sense, objects
in space. Transcendental idealism is the view that objects in space
are "outer" in the empirical sense but not in the
transcendental sense. Things in themselves are transcendentally
"outer" but appearances are not.


### 1.2 The Empirical Thing in Itself



Just as Kant distinguishes a transcendental from an empirical sense of
"outer" he also distinguishes a transcendental version of
the appearance/thing in itself distinction (the distinction we have
been concerned with up to now) from an empirical version of that
distinction. The key text here is A45-46/B62-63, which for
reasons of brevity will not be quoted in full (cf. the discussion of
the rose at A29-30/B45, as well as A257/B313).



In the empirical case, the distinction seems to be between the
physical properties of an object and the sensory qualities it presents
to differently situated human observers. This requires distinguishing
between what is "valid for every human sense in general"
and what "pertains to [objects] only contingently because [of]
... a particular situation or organization of this or that
sense" (A45/B62). The distinction seems to be that some
properties of objects are represented in experience just in virtue of
the *a priori* forms of experience, and thus have
inter-subjective validity for all cognitive subjects, while some
properties depend upon the particular constitution of our sense organs
(cf. A226/B273). The "empirical thing in itself" is the
empirical object *qua* bearer of the former set of properties,
while the "empirical appearance" is the empirical object
*qua* bearer of all of its properties, including the latter.
For instance, the empirical "rainbow in itself" is a
collection of water droplets with particular sizes and shapes and
spatial relations, while the empirical "rainbow
appearance" is the colorful band we see in the
 sky.[5]



For our purposes, the importance of this distinction is two-fold.
Firstly, the (transcendental) distinction is not the ordinary
distinction between how objects appear to us in sense perception and
the properties they actually have. Kantian appearances are not the
objects of ordinary sense perception, for Kant holds that appearances
*in themselves* (things in themselves, in the empirical sense)
lack sensory qualities like color, taste, texture, etc. In scientific
research, we may discover how appearances are *in themselves*
(in the empirical sense) but in so doing all we discover is more
appearance (in the transcendental sense); scientific investigation
into the ultimate constituents or causal determinants of objects only
reveals more appearance, not things in themselves. Secondly, there is
an appearance/reality distinction *at the level of
appearances*. This provides a further sense in which Kant is an
"empirical realist": appearances in themselves have
properties quite different than they seem to have in sense
perception.



Kant's empirical realism--not in his technical sense, but
in the broader sense that he accepts an appearance/reality distinction
at the level of appearances (see Abela 2002)--is further deepened
by his scientific realism: he accepts the existence of unobservable
entities posited by our best scientific theories and holds that these
entities are appearances (because they are in
 space).[6]
 Earlier, we saw texts whose *prima facie* meaning is that
appearances exist, at least partly, in virtue of the contents of our
representations of them. But it is clear that Kant cannot hold that
the existence of an object in space is grounded in our direct
perception of that object, for that would be incompatible with the
existence of unperceived spatial objects.


## 2. The Feder-Garve Review and Kant's Replies



The first published review of the *Critique of Pure Reason*, by
Feder and Garve (1782), accuses Kant of holding a basically Berkeleyan
phenomenalist conception of objects in space. Feder and Garve were not
the only ones to read Kant as a phenomenalist. The phenomenalist
reading was so widespread and influential that it became the default
interpretation for generations after the publication of the
*Critique*. In fact, many of the key figures in German
philosophy in 1781 and after (e.g., Mendelssohn, Eberhard, Hamann,
Jacobi, Fichte, Schelling) take the phenomenalist or
"subjectivist" reading of Kant for granted and think this
is precisely why Kant must be "overcome". The assumption
that Kant is a subjectivist about appearances is a major impetus in
the development of German
 idealism.[7]



However, the phenomenalist reading of transcendental idealism has been
challenged on many fronts, both as an interpretation of Kant and
(often on the assumption that it is Kant's view) on its own
philosophical merits. This section explores the origin of the
phenomenalist reading in the Feder-Garve review and its basis in the
text of the *Critique*. The next section provides some reasons
to think that the phenomenalist reading is more defensible as an
interpretation of Kant than is sometimes appreciated. Section 3.4
explores influential objections by Kant's contemporaries to
transcendental idealism, on the assumption that the phenomenalist
interpretation of that doctrine is correct, which were later taken up
as criticisms of the phenomenalist interpretation itself.
 Section 4
 introduces a theme explored in greater detail in later sections: the
development of non-phenomenalist interpretations of Kant's
transcendental idealism.


### 2.1 The Feder-Garve review



Although it is uncharitable and, on some points, simply mistaken, the
first published review of the *Critique*, originally written by
Christian Garve and then substantially revised, and shortened, by
J.G.H. Feder, raised an issue that has been discussed ever
 since.[8]
 The Gottingen, or "Feder-Garve" review, as it is now
known, claims that Kantian "transcendental" idealism is
just idealism of a familiar Berkeleyan or phenomenalist variety
(Sassen 2000: 53).



First of all, it should be noted that the Feder-Garve view, while not
exactly an exercise in interpretive charity, is not without a basis in
claiming that there is a deep similarity between Berkeley and the
*Critique* (this point is brought out well in Beiser 2002:
49-52). First of all, Kant repeatedly claims that empirical
objects *are* representations. For instance, in the
"Transcendental Aesthetic" he writes that "what we
call outer objects are nothing other than mere representations of our
sensibility" (A30/B45) and in the "Fourth
Paralogism" he writes: "external objects (bodies) are
merely appearances, hence also nothing other than a species of my
representations" (A370; see also A30/B45, A104 and A375n, A490,
A498, A563). Since "representation" [*Vorstellung*]
is Kant's term for what Berkeley calls "ideas", this
seems at least perilously close to the Berkeleyan view that bodies are
collections of ideas. Secondly, the A Edition is full of passages that
can easily suggest a phenomenalist view of objects in space, such as:




> 
> 
> Why do we have need of a doctrine of the soul grounded merely on pure
> rational principles? Without doubt chiefly with the intent of securing
> our thinking Self from the danger of materialism. But this is achieved
> by the rational concept of our thinking Self that we have given. For
> according to it, so little fear remains that if one took matter away
> then all thinking and even the existence of thinking beings would be
> abolished, that it rather shows clearly that if I were to take away
> the thinking subject, the whole corporeal world would have to
> disappear, as this is nothing but the appearance in the sensibility of
> our subject and one mode of its representations. (A383; cf. A374n,
> A490-1/B518-9, A520/B492-A521/B493, A494/B522)
> 
> 
> 



On one plausible reading of these passages, Kant is claiming that all
there is for objects in space to exist is for us to have experiences
as of objects in space. Consequently, if we did not exist, or did not
have such experiences, these objects would not exist. The Feder-Garve
interpretation of transcendental idealism is not without some
 merit.[9]


### 2.2 Varieties of Phenomenalism



Phenomenalism can mean many things, and later we will explore these
meanings in detail, but for now it is worth distinguishing at least
three different things we might mean by phenomenalism:



(1) 
 Objects in space are identical to (unified collections of) our
 representations.[10]
(2) 
 Objects in space exist solely in virtue of the contents of our
representations of them. They possess all of their properties solely
in virtue of the contents of those representations.
(3)
 Objects in space exist partly in virtue of the contents of our
representations of them. They possess their "core physical
properties" solely in virtue of the contents of those
representations.


"Core physical properties" here means the properties that
appearances have "in themselves" according to Kant. These
are, roughly, Lockean primary qualities (see Locke, *Essay
concerning Human Understanding*, book II, chapter VIII).
Feder-Garve accuse Kant of holding (1), which we may call
"identity phenomenalism". But even if he did not hold that
extreme view, he might hold one of the weaker views listed here. Claim
(2) is a quite strong form of phenomenalism, for it entails that, in
some sense, all there is to objects is our representations of them,
although they are not literally identical to those representation. We
may call this "strong phenomenalism". The exact meaning of
Berkeley's own views about bodies is unclear, and not the
subject of this entry. But it is not implausible to read Berkeley as
holding (2). However, claim (3), while very controversial and
(arguably) extremely counter-intuitive, is weaker. It allows that
there may be more to the existence of objects in space than our
representing them, and it allows that there may be aspects or
properties of objects that they possess independently of how we
represent them. We may call it "qualified phenomenalism".
In discussing the debate about Kant's alleged phenomenalism, and
Kant's own responses to the Feder-Garve review, it will help to
have these distinctions in mind.


### 2.3 Kant Strikes Back



Kant's was apoplectic that Feder and Garve had, apparently, not
made any serious attempt to even understand the *Critique*, or
to present its contents accurately to their readers. He penned a
response to the review, published as an appendix to the
*Prolegomena*. In the appendix, and in the text of the
*Prolegomena* itself, Kant explains what he sees as clear
differences between his own view and Berkeley's. First, Kant
identifies idealism as the doctrine that



> 
> 
> all cognition through the senses and experience is nothing but sheer
> illusion, and there is truth only in the ideas of pure understanding
> and reason (Ak. 4:374)
> 
> 
> 



and points out that, in this sense, his view is not idealism at all
because the *Critique* consistently maintains that bodies exist
in space and that we have immediate (non-inferential) knowledge of
 them.[11]
*Secondly*, Kant points out that his idealism is merely
*formal*: he has argued only that the *form* of objects
is due to our minds, not their *matter* (cf. Kant's Dec.
4 1792 letter to J.S. Beck (Ak. 11:395)). While the form-matter
distinction in Kant's philosophy is a complex matter in its own
right, Kant's point seems to be that the *matter* of
experience, the sensory content that is perceptually and conceptually
structured by space and time, and the categories, respectively, is not
generated by the mind itself, but is produced in our minds through
affection by mind-independent objects, things in themselves (see,
however,
 section 3.4
 for some reasons to be suspicious of the doctrine of "noumenal
affection"). As he would write several years later in response
to Eberhard, the *Critique* 



> 
> 
> posits this ground of the matter of sensory representations not once
> again in things, as objects of the senses, but in something
> super-sensible, which *grounds* the latter, and of which we can
> have no cognition. (*Discovery*, Ak. 8:205) 
> 
> 
> 



Thus, Kant can claim that only the form of experience is
mind-dependent, not its matter; the matter of experience depends upon
a source outside of the
 mind.[12]



However, Kant's attempts to distance himself from Berkeley may
not cut as deep as he seems to think. Regarding the first point,
Kant's definition of idealism in the Appendix (quoted above)
does not apply to Berkeley. Nor is it clear that his definition in the
body of the *Prolegomena* does either:



> 
> 
> the claim that there are none other than thinking beings; the other
> things that we believe we perceive in intuition are only
> representations in thinking beings, to which in fact no object
> existing outside these beings corresponds. (Ak. 4:289)
> 
> 
> 



One of the main points of Berkeley's philosophical project is to
defend the existence of bodies in space, while denying what he takes
to be a philosophical misinterpretation of what this existence amounts
to: the existence of non-thinking substances. Berkeley does not deny
that bodies exist; he claims that bodies cannot exist without minds to
perceive them, something that Kant himself also seems to accept (see
the texts quoted in the previous section). In fact, Berkeley
constantly contends that his theory is the only way to avoid what Kant
calls "problematic" idealism: we do not know whether
bodies exist (*Treatise on the Principles of Human Knowledge*,
Part I, SS 1, 6, 18, 20, 22-24, 34-38). That Kant
would describe Berkeley as an idealist in this sense (what he
elsewhere designates a "dogmatic idealist") raises the
suspicion that has misread
 Berkeley.[13]
 Since the misinterpretation of Berkeley as holding that sense
perception is illusory and that bodies do not exist was widespread in
Germany in the eighteenth-century (again, see Beiser 2002), it is
quite possible that Kant shares it. It may be that Kant is more
similar to Berkeley than he realizes because he is not familiar with
Berkeley's actual theory.



Nor does another point Kant makes--that Kant's idealism
concerns merely the form and not the matter of
experience--constitute a clear difference from Berkeley. Berkeley
does not claim that human spirits are the causes of their own ideas;
he claims that God acts on human spirits, causing us to perceive an
internally and inter-subjectively consistent world of ideas. Since
Kant's official doctrine in the *Critique* seems to
require agnosticism about the ultimate nature of the things in
themselves that causally affect us in experience, it is compatible
with what he says that the noumenal cause of experience is God
himself.



Kant's argument might be that the matter of experience (its
sensory content) depends upon how our sensibility is affected by
mind-independent objects, things in themselves, while the form of
experience is determined by our minds alone. Consequently, experience
itself requires the existence of objects "outside" (in the
transcendental sense) the mind. But this would show, at most, that
Kant is not a strong phenomenalist. It does not undercut the
interpretation of him as a qualified phenomenalist. Nor does it
succeed in clearly differentiating him from Berkeley. (See the
supplementary article:
 Kant's Attempts to Distance Himself from Berkeley.)
 This, of course, does not settle the issue; it may be that Kantian
appearances are quite different than bodies, as Berkeley, or even the
qualified phenomenalist, conceive them (for important discussions of
transcendental idealism in the *Prolegomena* see Ak.
4:283-4, 286, 289-294, 314-315, 320).


### 2.4 Changes in the B Edition



Kant extensively revised certain sections of the *Critique* for
the second edition (B), published in 1787. It is widely accepted that
a main consideration in these revisions was to avoid the
misunderstanding of his view that had led to the Feder-Garve review.
However, some scholars think that, on this point, there is a
difference in doctrine between the A and B editions: made aware of the
problematic Berkeleyan consequences of the first edition, Kant
endeavored to develop a more realistic view in the B
 Edition.[14]
 Other scholars think the difference is largely a matter of
presentation: in the B edition, Kant highlights the more realistic
aspects of his view and downplays its phenomenalistic sides, but the
view is basically the same (e.g., Allison 2004). The rest of this
section considers the main textual changes from 1781 to 1787 and
considers what implications they have for the interpretation of
Kant's idealism. Since Kant made no significant changes past the
Paralogisms chapter, sections that did not undergo substantial
revision will not be cited as evidence; it may be that Kant would have
significantly changed those sections if he had gotten there (on the
general topic of the changes from the A to the B edition, see Erdmann
1878).



Kant did, however, make one relatively minor alteration in the later
sections (in the "Antinomies", to be specific) that is
relevant to our discussion. In the wake of the Feder-Garve review,
Kant evidently felt that "transcendental" idealism may
have been a poor choice of
 name.[15]
 In the B Edition Kant adds a footnote to his definition of
transcendental idealism at A491/519 (quoted earlier) to remark that
perhaps he should have called his position "critical
 idealism".[16]
 The section Kant most heavily revised for the B Edition is the
"Transcendental Deduction", but there is not space here to
discuss the complex argument of that section, or the differences
between the A "Deduction" and the B
"Deduction".


#### 2.4.1 Objects as representations



As mentioned earlier, one of the main sources, both in the eighteenth
century and today, for the phenomenalist reading of Kant is
Kant's tendency to *identify* empirical objects with
representations. But Kant continues to do this in the B Edition, not
only in sections that were heavily revised for the B
 Edition[17]
 but even in passages that were added to the B Edition (e.g.,
B164).


#### 2.4.2 Preface



The B Preface contains several passages, which some scholars take to
be inconsistent with the phenomenalist reading. They are discussed
below in
 section 4.1.


#### 2.4.3 Transcendental Aesthetic



The main addition to the B "Transcendental Aesthetic" is
several pages (B66-69) at the end of the section, which includes
this discussion, a clear reference to the Feder-Garve review:



> 
> 
> If I say: in space and time intuition represents both outer objects as
> well as the self-intuition of the mind as each affects our senses,
> i.e., as it **appears**, that is not to say that these
> objects would be a mere **illusion**. [...] Thus I
> do not say that objects merely **seem** to exist outside
> me or that my soul only **seems** to be given if I assert
> that the quality of space [...] lies in my kind of intuition and
> not in these objects in themselves. It would be my own fault if I made
> that which I should count as appearance [*Erscheinung*] into
> mere illusion [*blossen Schein*]. (B70-1)
> 
> 
> 



This reiterates a theme found in the A edition and in the
*Prolegomena:* transcendental idealism does not entail that
objects in space are illusions. Later in the paragraph Kant argues
that, if we assume that if space and time must be "infinite
substances", if they exist at all, then we cannot blame Berkeley
for concluding that space, time, and bodies are mere illusions;
empirical idealism is the right conclusion to draw from transcendental
realism, according to Kant. While Kant is correct in representing
Berkeley later in this paragraph as reacting against the Newtonian
view of space and time as "absolute" entities, he is wrong
to characterize Berkeley as concluding that bodies are mere illusions,
so Kant's dissatisfaction with Berkeley's own view is not
evidence that he does not have a some variety of phenomenalist view of
objects in space. The B "Transcendental Aesthetic" adds no
new evidence against the phenomenalist reading.


#### 2.4.4 Paralogisms



One main source of the phenomenalist reading is the A Edition
"Fourth Paralogism", in which Kant refutes the
"Cartesian" view that our inner states are immediately
known while the existence of outer objects can only be known mediately
by inference from our inner states. The Paralogisms section was
entirely re-written in the B Edition, and none of the four B
Paralogisms correspond precisely to the fourth A Paralogism. The A
Edition "Fourth Paralogoism" is the source of many of the
passages quoted above, and, historically, an important source for the
phenomenalist interpretation. The fact that it was, effectively,
removed in the B Edition has led many scholars to reject the
phenomenalist interpretation, at least with respect to the B Edition
(with some averring that he changed his mind from the A to the B
 Edition).[18]
 A version of the A Paralogism argument that self-consciousness
requires knowledge of objects in space reappears as the
"Refutation of Idealism", added in the B Edition.


#### 2.4.5 Refutation of Idealism



Given its brevity, the "Refutation of Idealism", added to
the "Postulates of empirical thinking in general" in the B
Edition, is, line for line, one of the most thoroughly commented upon
passages in all of Kant's
 writings.[19]
 Kant's argument, very briefly, is that the existence of objects
in space outside me ("empirically external" objects) is a
condition on the possibility of my being conscious of the determinate
temporal relations of my inner states. Consequently, it is impossible
to be a self-conscious subject without there existing objects in space
outside of me, and in being conscious of the temporal relations of my
inner states I am immediately conscious of the existence of these
 objects.[20]
 The problem of "problematic idealism"--how can I
infer the existence of objects outside of me on the basis of my
immediate knowledge of my inner states?--is based on a false
premise.



Nothing about this conclusion, or how Kant argues for it, is *prima
facie* incompatible with a qualified phenomenalist reading of
transcendental idealism, or even a strong phenomenalist
 one.[21]
 It may be incompatible with "identity" phenomenalism,
since Kant argues that self-consciousness requires the existence of
permanent objects in space, yet there is no permanent representation
in the mind (B278). If objects just are representations, it follows
that none of them are
 permanent.[22]
 At B274 Kant makes it clear that the "idealism" that he
intends to refute is idealism as he defined it in the
*Prolegomena* and the "Fourth A Paralogism": the
claim that objects in space do not exist (dogmatic idealism) or at
least that we do not know whether they exist (problematic idealism).
The sense of idealism that is at issue in the phenomenalist
reading--empirical objects exist, and exist in virtue of the
contents of experience--is not, apparently, addressed here. On an
extreme phenomenalist reading, all there is to the existence of
empirical objects in space is our having appropriately unified
experiences of them. The phenomenalist can interpret Kant's
argument in the "Refutation" as an argument that
consciousness of the temporal relations of my inner states requires
that these inner states constitute appropriately unified experiences.
Consequently, self-consciousness requires the existence of objects in
space (spatially) outside
 me.[23]
,
[24]


#### 2.4.6 General note to the principles



In the B Edition Kant added a "General Note" to the
"Principles of Experience", which some have read as ruling
out the phenomenalist reading, especially the long passage from B291
to 294 (excerpted here):



> 
> 
> This entire remark is of great importance, not only in order to
> confirm our preceding refutation of idealism, but, even more, when we
> come to talk of **self-cognition** form mere inner
> consciousness and the determination of our nature without the
> assistance of outer empirical intuition, to indicate to us the limits
> of the possibility of such a cognition. (B293-4)
> 
> 
> 



Once again, this is a case of Kant emphasizing that his view is not
idealist *in the specific sense of idealism we have seen so
far*--denying either that objects exist in space or that we
can know that they do. His point is that even understanding our most
basic *a priori* concepts, the categories, requires applying
them to outer objects in space. The remark about
"self-cognition" at the end is a reminder that inner
awareness is dependent upon outer experience; it does not address
whether empirical objects exist (partly or wholly) in virtue of the
contents of experience.


#### 2.4.7 Phenomena and noumena



Kant extensively revised the section entitled "On the grounds of
the distinction of all objects into phenomena and noumena" in
the B Edition. However, since that section concerns the Kantian notion
of "*noumena*", discussion of it is reserved until
 SS6,
 which is devoted to that notion, its relation to the "thing in
itself", and the related notion of the "transcendental
object".


## 3. Kant as a Phenomenalist



So far, we have seen the *prima facie* evidence for the
phenomenalist interpretation of Kant, made famous by Feder-Garve, and
Kant's own attempts to distance himself from their accusations.
However, we also distinguished three different kinds of phenomenalism:
identity phenomenalism, strong phenomenalism, and qualified
phenomenalism. This section explores the interpretation of Kant as
qualified phenomenalist, and explores how a defender of this
interpretation might answer some of the standard objections to the
phenomenalist reading.


### 3.1 Appearances = representations?



While the identity phenomenalist interpretation has found few
defenders among contemporary readers (Guyer 1987: 333-336 is a
notable exception; for critical discussion, see Allison 2004:
8-9), it is worth asking why exactly we should reject the
*prima facie* meaning of the numerous passages in which Kant
equates appearances with representations.



Perhaps the best reason to reject the identity phenomenalist
interpretation is that it is incompatible with many of the very texts
that are used to motivate it (there is also the lingering problem of
whether it is compatible with the "Refutation of
Idealism"; see
 section 2.4.
 and part IV of Guyer 1987). In many of the texts in which Kant
identifies appearances with (a species of) representations, he also
claims that representations are representations *of*
appearances, i.e., that representations are representations of
objects, appearances. For instance,



> 
> 
> [...] external objects (bodies) are merely appearances, hence
> also nothing other than a species of my representations, whose objects
> are something only through these representations, but are nothing
> separated from them. (A370-1)
> 
> 
> 
> everything intuited in space or in time, hence all objects of an
> experience possible for us, are nothing but appearances, i.e., mere
> representations, which, as they are represented, as extended beings or
> series of alterations, have outside our thoughts no existence grounded
> in itself (A490-1/B518-9; Allison (2004: 36) attempts to
> explain away the apparently phenomenalist implications of this
> passage)
> 
> 
> 



In both passages, Kant describes appearances as representations but
also as *objects* of representation. If this is correct, then
Kant thinks that the sense in which an appearance *is* a
representation is compatible with it being the object of a
representation. For instance, the sense in which this table
"is" a representation is compatible with it being the
object of my perception *of* it. Assuming that the
representations that empirical objects "are" are not
always self-representational (e.g., the table is not identical to a
table-ish visual perception that also represents itself), it follows
that the objects cannot be identical to our representations of them.
For instance, my visual perception of this table cannot *be*
this table, because my visual perception does not (presumably)
represent itself. To make the identity phenomenalist view consistent
with the very texts that motivate it, we need to "double"
our representations: a visual perception of the table and then the
representation that the table is. But what could that representation
be? It must be present when and only when the table exists (because
they are identical), and my perception of the table must be
intentionally directed *at it*. While this is not conclusive,
it is evidence that the identity phenomenalist interpretation should
be abandoned.



Is there any way to free Kant from the apparent consequences of his
tendency to identify appearances with representations of them? One
standard strategy is to say that Kant is simply being sloppy: he means
that appearances are the objects of our representations, not that they
literally are those
 representations.[25]
 However, the passages in question occur throughout the
*Critique*, in both editions, and they remain after Feder-Garve
pointed out their apparently phenomenalist implications. On the other
hand, their persistence in the B Edition suggests that they do not,
and never were intended to, commit Kant to a form of identity
phenomenalism. How could Kant claim Feder-Garve had misunderstood him
if he had identified appearances with representations? This suggests
that another reading is possible, but does not tell us what it is.



One strategy would be to claim that Kant does not mean the
"is" of identity, but the "is" of grounding.
Sometimes, apparent claims of identity are really claims about
grounding relations. For instance, if I say "pain is C-fiber
firing" I might mean the type-identity thesis that the state of
being in pain is the state of C-fiber firing. But I might also mean
that all there is to pain is C-fiber firing, that if one is in pain it
is in virtue of C-fiber firing, or that C-fiber firing non-causally
grounds the state of being in pain. On this view, in claiming that
appearances *are* representations, Kant is claiming that the
contents of representations ground the existence and empirical
properties of appearances.



But this is not the plain meaning of the relevant passages. At A371
Kant claims that appearances are a species (*Art*) of
representations; while "is" can be interpreted in a number
of ways (e.g., the "is" of constitution), it is hard to
interpret "*A*s are a species of *B*s" in
any other way than: every *A* is a *B*, which means
every *A* is identical to a *B* (namely, itself). While
there may be something to the "grounding" interpretation
of these passages, there are good reasons to think these texts have
not been explained (or explained away).



A third alternative, proposed by Wilfred Sellars, and which may
ultimately face the same problem, relies on the Cartesian distinction
between the formal and objective reality of representations (in
Cartesian terminology,
 ideas).[26]
 The objective reality of an idea is the representational character of
the idea, its character as a representation with a certain content.
Consequently, we can talk about the object of an idea without assuming
that there is an object "external" to the idea; to talk of
the "internal" object of the idea is just to talk about
that idea's objective reality. For instance, we can coherently
talk about God without presupposing that God exists
"outside" our idea of him; this God-talk is to be
understood as talk about our idea of God in its objective realty,
i.e., to talk about the content of our God-idea. Translating this back
into Kant, we might take his claims that appearances are
representations as claims to the effect that appearances are
representations *considered in their objective reality*, or, in
other words, that talking about appearances, objects of
representations, is just talking about representations and their
contents.



There are at least two problems with this strategy, however. For one,
it is arguably no less a distortion of the plain letter of the text
than the other interpretations. If Kant meant that appearances are
representations *considered with respect to their objective
reality* why didn't he simply say that, rather than stating
that they *are* a species of representations? Secondly, it is
far from clear that, on Kant's view, *talk* about
appearances is equivalent to *talk* about the objective reality
of representations. Kant may not be attempting a semantic analysis of
appearances in terms of representations. To many readers, it has
seemed more plausible to read Kant as claiming that appearances are
*grounded* (non-semantically) in representations and their
objective reality (content). So this proposal may collapse into the
previous one.


### 3.2 Qualified phenomenalism



Kant repeatedly claims that our representations alone do not ground
the existence of their objects. At A92/B125 he writes that
"representation in itself does not produce its objects in so far
as existence is concerned" and in a 1792 letter to J.S. Beck he
dismissed the Feder-Garve interpretation with one line: 



> 
> 
> I speak of ideality in respect of the *form* of representation,
> while they construe it as ideality in respect of the *matter*,
> i.e., ideality of the object and its existence. (Ak. 11:395)
> 
> 
> 



The first passage could be taken to mean that the existence of
empirical objects is not *wholly* grounded in the contents of
our experience; something else must be added. The second passage could
be taken to mean that Feder and Garve misattributed to him the
opposite view: that all there is to the existence of an object in
space is our having mental states with a certain content. But all this
shows is that *strong* phenomenalism is not Kant's view.
It leaves open the possibility that he accepts *qualified
phenomenalism*: the existence of objects in space is grounded
partially, and their core physical properties are grounded wholly, in
the contents of our representations of them.



The first question to be answered is, what, in addition to the
contents of our representations, grounds the existence of empirical
objects? The natural answer, for the qualified phenomenalist, is that
there must be things in themselves that appear as these objects. Kant
repeatedly insists that it is a conceptual truth that appearances are
appearances of something that is not itself an appearance, a thing in
itself (e.g., A251-2, Bxxvi-xxvii, B306, B307, and Ak.
4:314-5). On the qualified phenomenalist reading, this means
that the existence of an appearance requires (a) a representation of
an object, and (b) a thing in itself that appears as that object. A
fully developed qualified phenomenalist reading would require saying
precisely what it means for a thing in itself to appear as an
empirical object (an object of experience), but for reasons of space
only a sketch of an answer can be given here. At the minimum, the
qualified phenomenalist should require that the thing in itself
causally affect the experiencing subject, and that the sensory content
thus produced be involved in the experience of the object. Some
scholars have suggested that the properties of appearances are
structurally isomorphic to the properties of things in themselves, but
that idea will not be further pursued here (e.g., Findlay 1981:
92-93; see also Van Cleve 1999: 155-162).



The qualified phenomenalist also owes us an answer to the question,
which are the representations whose content partly grounds the
existence of empirical objects and wholly grounds their core physical
properties? The natural answer is "experience", so the
qualified phenomenalist owes us an interpretation of what Kant means
by "experience", what its content is, and how it grounds
(partly) the existence and (wholly) empirical properties of
 appearances.[27]
 We have already seen that, for familiar reasons, Kant cannot ground
the existence of empirical objects in our mere perceptions of them:
sometimes we misperceive objects, objects exist while unperceived, and
there are objects we cannot ever directly perceive.



There have been few worked-out phenomenalist interpretations of Kant
in the secondary literature. An outline of one such reading is
presented in what follows in order to present the reader with some
more determinate idea of what a qualified phenomenalist reading might
look like and why
 (section 3.3)
 some of the classic objections to phenomenalist interpretations may
be less devastating than they are sometimes presented. But this is not
meant to give the impression that this is the only plausible
phenomenalist reading of Kant.



The qualified phenomenalist grounds the existence of objects (partly)
and their core physical properties (wholly) in the content of
experience. But this requires a conception of experience on which it
is not identical to any individual subject's perceptual
episodes; otherwise, objects will have contradictory properties if,
for instance, I see the tower as round and you see it as square. Kant
distinguishes experience from perception in the A
"Deduction", writing:



> 
> 
> There is only **one** experience, in which all
> perceptions are represented as in thoroughgoing and lawlike connection
> [...] If one speaks of different experiences, they are only so
> many perceptions insofar as they belong to one and the same universal
> experience. (A110).
> 
> 
> 



In this sense of experience ("universal experience") there
is only one experience. It may also be that, inter-subjectively, there
is only one universal experience as well: my perceptions and your
perceptions are only "experiences" to the extent that they
cohere with the one universal experience. Kant, in this passage, does
not tell us much about what universal experience is, or what its
contents are. He does tell us that it is composed from perceptions,
that it has an *a priori* form (space, time, and categories),
and that the perceptions that constitute it are in
"thoroughgoing and lawlike connection".



Elsewhere, he sheds further light on the coherence relation that
defines universal experience:



> 
> 
> In space and time, however, the empirical truth of appearances is
> satisfactorily secured, and sufficiently distinguished from its
> kinship with dreams, if both are correctly and thoroughly connected up
> according to empirical laws in one experience. Accordingly, the
> objects of experience are never given in themselves, but only in
> experience, and they do not exist at all outside it. (A493/B521)
> 
> 
> 



Perception *P**n* coheres with perceptions
*P*1 through *P**n*[?]1
to the extent that the causal laws observed in *P*1
through *P**n*[?]1 are observed in
*P**n*. This gives us reason to exclude
hallucinatory perceptions from universal experience: hallucinatory
perceptions involve apparent violations of the causal laws that are
observed to hold in our "waking" perceptions, so they do
not cohere with those other perceptions.



We know *a priori* something very general about the form of
universal experience, of course: it will be spatiotemporal and the
principles of experience (applications of the categories) will hold in
it. But that does not determine the determinate *a posteriori*
content of universal experience, and the idea of a qualified
phenomenalist analysis of empirical objects is to hold that their
existence and empirical properties are (partly and wholly,
respectively) grounded in that fully determinate *a posteriori*
content. So we might begin with the following analysis:



(*Experience*) Universal experience consists in the largest
internally coherent subset of perceptions that obeys the principles of
experience. A subset of perceptions is internally coherent to the
degree to which causal regularities hold among its contents.



On a qualified phenomenalist reading of Kant, this might be taken as
the set of representations whose content grounds objects. However,
there are at least two problems with this analysis of universal
experience:



(i)
 *Unperceived objects*. Kant holds that there are
spatiotemporal objects we cannot perceive. This by itself would pose a
problem for the proposed definition of universal experience, since, on
the qualified phenomenalist view, that definition entails that there
cannot be unperceived spatiotemporal objects. But Kant further claims
that we can *experience* unperceivable objects through
perceiving their effects and inferring their existence from causal
laws. So the definition of universal experience needs to be refined
(A226/B273; Langton (1998: 186-190).
 (ii) 
 *Secondary qualities*. As we discussed above in the
section on Kant's empirical realism, Kant distinguishes between
the properties spatiotemporal objects actually have "in
themselves" and those they merely appear to have in sense
perception. He has a basically Lockean distinction between primary and
secondary qualities at the empirical level. Since we perceive objects
as having secondary qualities, the definition of universal experience
given above, combined with the qualified phenomenalist analysis,
entails that empirical objects have secondary qualities. We need to
further refine our definition of universal experience to eliminate
secondary qualities from the empirical properties of objects.


We need to refine the conception of experience so as to include
unperceived objects and exclude secondary qualities. This might push
us towards a more "scientistic" conception of universal
experience, on which experience is something like the ideal scientific
theory of objects in space and
 time.[28]
 The form of that theory is *a priori* determinable from the
forms of experience: it will represent persisting substances in a 3-D
Euclidean space obeying universal causal laws and in simultaneous
mutual interaction. However, the determinate *a posteriori*
content of that theory will be grounded in the perceptions subjects
actually have.



Here is a sketch of a conception of universal experience that the
qualified phenomenalist might accept:



(*Experience*) Universal experience is the maximally unified
and lawful representation of objects in space and time that is
compatible with the *a priori* forms of experience and
justified by the totality of subjects' perceptual states, or the
conjunction of such representations if there is no unique such
 representation.[29]



To fully develop such a view, a lot more would have to be said about
exactly how the content of experience is grounded in, and justified
by, the contents of subjects' perceptual states, but this gloss
is enough to give us a sense of what a developed phenomenalist reading
of Kant might look like.


### 3.3 Criticisms of Phenomenalist Readings



Since the Feder-Garve objection to Kant has been around almost as long
as the *Critique* itself, many objections to broadly
phenomenalist readings of Kant's idealism have accumulated.
Perhaps the most comprehensive list of such objections is given by
Allais (2004). They include:


* *"*Kant's claim that his notion of appearance
implies that there is something that appears". We have already
discussed how the qualified phenomenalist can accommodate this
point.
* *"*Empirically real objects and the space they
inhabit are public". Allais seems to assume that, on a
phenomenalist analysis of objects in space, objects are
"private", meaning the objects each subject perceives are
constituted by sense data of that subject, which, by definition,
cannot be perceived by other subjects. But the qualified phenomenalist
conception of universal experience sketched above is explicitly
"non-private" in this sense; it is based on the
perceptions of *all* subjects.
* "Kant's distinction between primary and secondary
qualities". However, the qualified phenomenalist can claim that
while our perceptions represent objects as having secondary qualities,
the best scientific theory justified by the totality of those
perceptions (universal experience) does not represent them as having
those properties, because there is a better theory available: objects
do not possess such properties but do possess powers to cause us to
perceive them as having such properties. There is, in principle, no
barrier to a qualified phenomenalist allowing the distinction between
primary and secondary qualities.
* "Kant's realism about the unobservable entities of
theoretical science". Kant is a scientific realist, in that he
accepts the existence of unobservable entities posited by our best
physical theories (magnetic matter, Newtonian "lamellae").
Allais thinks this is incompatible with a phenomenalist reading, but
it is compatible with the conception of universal experience developed
in the previous section. If universal experience has the content of
the scientific theory best justified by our perceptions, then
universal experience can represent unobservable (=unperceivable)
objects (cf. Allison (2004: 46)) who also objects that phenomenalism
is incompatible with Kant's empirical realism).
* "Empirically real objects exist through time and
unperceived, and are in causal relations". The fact that
empirically real objects exist through time while unperceived might be
thought to pose a problem for phenomenalism, although it should be
remembered that Berkeley (at least on some readings) is a
phenomenalist and yet accepts that objects exist while unperceived
(although he denies that they stand in causal relations). So it
isn't clear why Allais think this is incompatible with
phenomenalism. And it clearly is compatible with the conception of
universal experience developed in the previous section: experience
represents objects as existing through time and unperceived, because a
theory that represents them as existing only when perceived would be
far less unified and lawful.
* "We do not know what ideas are in themselves".
Allais's idea seems to be that the phenomenalist is committed to
grounding empirical objects not in "empirical ideas"
(temporally ordered mental states available in conscious
introspection) but in "noumenal ideas" (the non-temporal
states of the subject in itself). But it is unclear why; the
phenomenalist conception of experience developed in the previous
section explicitly grounds the *a posteriori* content of
universal experience in "empirical" ideas, the totality of
subjects'
 perceptions.[30]



Allais appears to have conflated phenomenalist readings of Kant in
general with the "strong" phenomenalism (or even identity
phenomenalism) discussed in
 section 2,
 and one, moreover, that identifies experience with mere
perception.


### 3.4 The Problem of Things in Themselves



No discussion of Kant's transcendental idealism would be
complete without a discussion of F.H. Jacobi's famous objection
to the critique:



> 
> 
> without the presupposition of the [thing in itself] I cannot enter the
> [critical] system, and with that presupposition I cannot remain in it.
> (Jacobi, *Werke*, vol. II, p. 304)
> 
> 
> 



Jacobi is referring to a number of quite serious problems for
Kant's transcendental idealist theory. They do not disappear on
other interpretations, but they are especially serious for the
traditional phenomenalist reading. Unlike the problems we discussed
earlier, however, which were specifically problems for the
phenomenalist analysis of *appearances*, these problems, as
Jacobi indicates, concern the thing in itself, and the relation
between things in themselves and appearances.


#### 3.4.1 The Unknowability of Things in Themselves



Kant is committed to both of the following theses:



(*Existence*) There are things in themselves.



(*Humility*) We know nothing about things in themselves.



While these are not, strictly speaking, incompatible, they are in
tension, for *Humility* appears to remove any warrant Kant
might have for asserting *Existence*.



But it gets worse for the traditional view. Kant does not merely claim
that things in themselves *exist*, he also asserts that,



(*Non-spatiality*) Things in themselves are not in space and
time.



(*Affection*) Things in themselves causally affect
 us.[31]



Many of Kant's early readers concluded that Kant's
philosophy is inconsistent: he claims that we cannot know the very
assertions he makes about things in themselves. Kant's own
theory renders itself
 unknowable.[32]



It would be over-hasty to suggest that each of these three
problems--how to square Humility, with Non-Spatiality, Affection,
and Existence--are on a par. Since Non-spatiality makes only a
negative claim, it may be easier to make it consistent with Humility.
For instance, at B149 Kant writes:



> 
> 
> it is not yet a genuine cognition if I merely indicate what the
> intuition of the *object* is not, without being able to say
> what is then contained in it.
> 
> 
> 



This suggests that, while Kant's usually unqualified statements
of our ignorance of things in themselves (they are "not cognized
at all" A30/B45), his considered view might be more qualified:
we know nothing of the positive properties of things in
 themselves.[33]
 But *Affection* looks especially difficult to square with
*Humility* (see Hogan 2009 and Stang 2013).


#### 3.4.2 Things in themselves as causes



The issue of things in themselves *affecting* us raises another
problem for Kant's theory, for Kant also argues that categories
like *cause-effect* cannot be meaningfully applied to things in
themselves. Without an intuition "[the category] has no sense,
and is entirely empty of content" (A239/B298). Since things in
themselves cannot be intuited, categories (including
*cause-effect*) have no sense or content when applied to things
in themselves. Jacobi and others thought this was yet another
inconsistency in Kant's philosophy: he denies that categories
can be applied to things in themselves, but then he applies the
category cause-effect to them!



However, one has to be careful in interpreting Kant's denial of
"sense" or "meaning" to categories as applied
to things in themselves. It is tempting to read this as meaning that
the thought of things in themselves falling under categories is
literally nonsense, but there is textual evidence that Kant is making
a weaker point: thinking of things in themselves under the categories
has no *cognitive* sense, i.e., in making such judgments we do
not *cognize* anything. For instance,



> 
> 
> [...] the categories are not restricted in
> **thinking** by the conditions of our sensible intuition,
> but have an unbounded field, and only the **cognition**
> of objects that we think, the determination of the object, requires
> intuition; in the absence of the latter, the thought of the object can
> still have its true and useful consequences for the
> **use** of reason [...]
>  (B166n)[34]
> 
> 
> 



We can think of any objects whatsoever using the categories. In fact,
this is unavoidable; the categories are the most basic concepts of
objects in general, so we cannot think about anything whatsoever
without using some categories to do so. But in thinking about the
things in themselves using categories we do not *thereby* (a)
know that there are things in themselves falling under the categories
or (b) even that it is *possible* for there to be things in
themselves falling under the categories. The strongest form of
Jacobi's objection--that Kant's view entails that the
categories cannot be applied, even in thought, to things in
themselves--may rest on a misunderstanding (cf. Van Cleve 1999:
137; Adams 1997: 820-1). This still leaves, though, the pressing
problem of how, given Kant's Humility doctrine, he could have
any epistemic warrant for making the various substantive claims he
does about things in themselves (Existence, Non-spatiality,
Affection).


#### 3.4.3 The Problem of Affection



Jacobi raises yet another problem about Kant's theory of
experience. He notes Kant's definition of sensibility as the
capacity "to receive representations through the manner in which
we are affected by objects" (A19/B33) and poses a dilemma: are
the objects that affect our sensibility appearances or things in
themselves? They cannot be things in themselves, Jacobi argues,
because that would involve applying the categories to things in
themselves. And they cannot be appearances, because appearances exist
in virtue of the very experiences they are (allegedly) causing. He
concludes that Kant's system is inconsistent (Jacobi,
*Werke*, vol. II, 291-310; Fichte raises the same
objection in the Second Introduction to the
*Wissenschaftslehre*; cf. Fichte, *Werke* I, 488).



We have already discussed the argument of the first horn of
Jacobi's dilemma: we can think but not *know* that things
in themselves causally affect us. But what about the second horn? Hans
Vaihinger concisely explains Jacobi's argument:



> 
> 
> Or one understands by affecting objects the objects in space; but
> since these are only appearances according to Kant, and thus our
> representations, one falls into the contradiction that the same
> appearances, which we first have on the basis of affection, should be
> the source of that very affection. (Vaihinger 1881: vol. 2, p. 53)
> 
> 
> 



"First" here does not refer to temporal priority, but to
metaphysical priority: if *p* is true in virtue of *q*,
then *q* is "prior" to *p*. Jacobi and
Vaihinger assume that appearances exist in virtue of the contents of
our experience of them:



(*Trans. Idealism*) If *x* is an appearance, then
*x* exists in virtue of the fact that subjects experience
*x*.



If we are empirically affected, though, it follows that:



(*Empirical affection*) For some *x*, *x* is one
of the causes of subjects' experience of *x*.



For instance, this computer is one of the causes of my current
experience of it. But these assumptions are inconsistent if we assume
the following plausible principle:



(*Exclusion*) If *x* exists in virtue of the fact that
*p*, then *x* cannot be even a partial cause of the fact
that *p*.



Intuitively, this principle says that no object can be even a partial
cause of the very fact in virtue of which it exists; if it were, it
would be a partial cause of its own existence. In the context of
Kant's theory of experience, it means that appearances cannot
"reach back" and cause the very experiences in virtue of
which they exist. From the 1780s until today, many have taken this
problem to be fatal to Kant's theory of
 experience.[35]


## 4. The "Dual Aspect" View



Because the phenomenalist interpretation of transcendental idealism
held such sway, not only among Kant's contemporaries, but for
generations of German philosophers as well, these problems for the
phenomenalist construal of transcendental idealism were taken to be
evidence that Kant's view itself is
 inconsistent.[36]
 In the twentieth century, the phenomenalist (or
"Berkeleyan") interpretation of transcendental idealism is
associated with P.F. Strawson, whose massively influential (1966)
argued that, for many of the reasons we have seen, transcendental
idealism was a blunder on Kant's part (Strawson 1966: 16,
38-42, 253-73). However, Strawson claimed, the core
arguments of the *Critique* do not in fact rely on it and can
be reconstructed independently of it.



In the 1960s and 1970s a group of scholars, in some cases in direct
opposition to Strawson, developed a non-phenomenalist,
anti-metaphysical reading of transcendental idealism, the "dual
aspect"
 view.[37]
 These scholars took the textbook problems for phenomenalism
(especially, the problem of affection) as evidence that this was the
wrong interpretation of Kant's position to begin with. They
sought to rescue transcendental idealism from what they took to be the
phenomenalist misconstrual, defend its philosophical cogency from its
detractors, and show, contra Strawson, that the central arguments of
the *Critique* do rely on transcendental idealism. This was as
much a philosophical defense of Kantian transcendental idealism as it
was an interpretive-exegetical project.



They developed what has become known as the "dual aspect"
view. They argue that many of the classic problems for the
phenomenalist reading (e.g., affection) arise because it was
mistakenly assumed that appearances and things in themselves are
distinct kinds of objects. They argued instead that the
appearance/thing in itself distinction is not an ontological
distinction between two kinds of objects, but an adverbial distinction
between two different perspectives or stances we can take on one and
the same set of objects: we can consider them as they appear, or as
they are "in themselves".


### 4.1 One Object, Not Two



In numerous passages, Kant describes the appearance/thing in itself
distinction, not as a distinction between two different objects, but
as a distinction between two ways of considering one and the same
object. For instance,



> 
> 
> [...] the same objects can be considered from two different
> sides, **on the one side** as objects of the senses and
> the understanding for experience, and **on the other
> side** as objects that are merely thought at most for isolated
> reason striving beyond the bounds of experience. (Bxviii-Bxix,
> note)
> 
> 
> 
> [...] the reservation must well be noted that even if we cannot
> cognize these same objects as things in themselves, we are lat least
> able to **think** of them as things in themselves.
>  (Bxxvi)[38]
> 
> 
> 



The general characteristic of such passages is that they use the same
chain of pronouns to refer both to appearances and things in
themselves. This strongly suggests that *one and the same*
object can be an appearance and a thing in itself, or, to put it
another way, the distinction between appearance and thing in itself is
not a distinction between two or more objects, but a distinction
between two different aspects of, or ways of considering, one and the
same object. One and the same object can be considered *as it
appears to us* in experience, or *as it is in itself*.
Considered in the former way, the object must conform to our *a
priori* intuitional forms, so it is in space and time. Considered
in the other way, the object may not be in space and time. Some
"dual aspect" readers cite the increased frequency of such
passages in the *Prolegomena* and the B Edition as evidence
that Kant, realizing that his distinction between two aspects of
objects was being conflated with a distinction between two kinds of
objects, sought to remedy this interpretation by emphasizing precisely
this point. Prauss (1974) notes that, in most cases, Kant uses the
expression "*Dinge* [*Sachen*, *Objecte*,
*Gegenstande*] *an sich selbst*" rather than
the shorter form "*Dinge an sich*". He argues that
"*an sich selbst*" functions as an adverb to modify
an implicit attitude verb like "to consider"
[*betrachten*]. He concludes that the dominant use of these
expressions is as a short-hand for "things considered as they
are in themselves" (Prauss 1974: 14-15).



Different scholars understand this distinction in different ways. The
main difference is between epistemological and metaphysical
"dual aspect" interpretations (Allison 2004: 52). On the
epistemological reading, the distinction between appearances and
things in themselves is simply a distinction in the standpoint from
which we consider them. We can consider objects as objects of
knowledge for discursive spatiotemporal cognizers like us, in which
case we are considering objects as *appearances*. Or we can
abstract from our particular cognitive conditions and consider objects
merely as objects for a mind in general, in which case we are
considering them as *things in themselves*. It is crucial to
the epistemological reading that there is no sense in which the
"transcendental" perspective on objects as *things in
themselves* gets at how objects "are in themselves".
The point of Kant's transcendental idealism, epistemological
interpreters stress, is to get away from the incoherent idea of a
"view from nowhere" in which we could know objects as they
"really are in
 themselves".[39]



By contrast, metaphysical "dual aspect" interpreters take
the distinction to carry more metaphysical weight. They interpret the
appearance/thing in itself distinction as a metaphysical distinction
between two different classes of properties had by objects, for
instance, their relational properties and their intrinsic properties.
Appearances are objects *qua* bearers of "empirical
properties" (e.g., relational properties) while things in
themselves are *the very same objects* *qua* bearers of
"noumenal" or "non-empirical" properties
(e.g., intrinsic properties). The next two sub-sections explore the
epistemological interpretation of Henry Allison. The remainder of the
sections concerns metaphysical "dual aspect" readings,
focusing on the widely discussed interpretation of Langton (1998).


### 4.2 Allison's "Epistemic" reading



In modern Kant scholarship, the epistemic reading was first put
forward by Gerold Prauss, Henry Allison, and Graham Bird. Since
Allison's work was the most influential among English language
scholars, and most likely to be known to readers, this discussion will
focus on the interpretation of transcendental idealism in Allison
(1983) and the revised and enlarged second edition (2004).
Allison's writings contain several distinct (and not obviously
equivalent) formulations of transcendental idealism. This section
concentrates on reconstructing what is arguably the "core"
of Allison's reading: his interpretation of appearances and
things in themselves, and his reconstruction of the argument for the
non-spatiality of things in themselves.



The core insight of Kant's epistemology in general, and his
transcendental idealism in particular, according to Allison, is the
principle that we possess a *discursive* intellect. A
discursive intellect is one that passively receives representations of
particular objects (intuitions) and then spontaneously subsumes those
intuited objects under general concepts; consequently, a discursive
intellect must possess a sensory faculty (through which it receives
sensory data and intuits individual objects) and a conceptual faculty
(through which it forms general concepts and applies them to objects)
(A50-1/B74-5). By contrast, an intuitive intellect brings
into existence its objects merely by representing them, and thus has
no need to receive representations of objects from
 outside.[40]
 But that is not all there is to the discursive nature of our
intellect, Allison
 argues.[41]
 Kant's key insight is that our sensible faculty has its own
epistemic conditions.



An "epistemic condition" is Allison's term for a
representation we must apply to objects in order to cognize them
(Allison 2004: 11, 14). Space and time are epistemic conditions, as
are the categories. If *E* is an epistemic condition then
necessarily if we know an object *O*, in knowing it we
represent it using
 *E*.[42]
 Some of our epistemic conditions follow from the general fact that we
are discursive cognizers (the categories) and some follow from the
more specific fact that we cognize objects given to us in space and
time. Representing objects using the categories is an epistemic
condition for any discursive intellect, i.e., for any intellect that
must conceptualize objects given passively in sensory
 intuition.[43]
 So space and time are epistemic conditions of spatiotemporal
discursive cognition of objects, while the categories are epistemic
conditions of discursive cognition of objects *in general*. Any
discursive intellect must conceptualize sensibly intuited objects
using the categories, whether or not those objects are intuited in
space and time, or some other intuitional forms (Allison 2004:
17).



This grounds a distinction between two ways of considering the objects
of our cognition. When we consider objects *qua* objects of our
cognition, we consider them as falling under the relevant epistemic
conditions. If *E* is an epistemic condition of cognition of
objects, then objects must fall under *E* (i.e., be accurately
represented by *E*); otherwise, in representing them with
*E*, I would not be cognizing objects but misrepresenting them.
My representation of objects with *E* would be an illusion, the
very conclusion Kant wants to avoid with respect to space and objects
represented in space. This means that if *E* is an epistemic
condition of the specific kind of discursive cognition of objects that
we have, then *E* correctly represents those objects. So, if
space and time are the forms of our intuition, it follows that
empirical objects *qua* objects of the kind of discursive
intellect we have, are in space and time. But if we do not consider
objects *qua* objects of our specific kind of discursive
intellect, but *qua* objects of discursive intellect in
general, we can no longer assume that our specific intuitional
epistemic condition applies to them. The more general epistemic
conditions of all discursive cognition (in Kant's view, the
categories) still apply to objects under this more abstract
perspective, however. So we can say that objects *qua*
appearing (objects of spatiotemporal discursive cognition) are in
space, but *qua* things in themselves (objects of discursive
cognition in general) they are not in space. This, in a nutshell, is
Allison's reconstruction of the argument for the non-spatiality
of things in
 themselves.[44]
 While it is legitimate to consider objects as things in themselves
using the categories, we do not thereby *cognize* them. This
follows trivially from the fact that space and time are epistemic
conditions for us: without representing objects in space and time, we
can think of objects using the categories, but those thoughts are not
cognitions (Allison 2004: 18).


### 4.3. Problems with the Epistemic reading



Allison's interpretation has been challenged on a number of
points by other scholars. This section discusses a number of such
objections.


#### 4.3.1 The Triviality Objection



Some scholars object that Allison's reading of the
non-spatiality thesis, and the thesis that things in themselves are
uncognizable by us, renders it a tautology, a trivial logical
consequence of
 definitions.[45]
 We may represent the definition of "thing in itself" talk
(on Allison's interpretation) as follows:



(1)
Things in themselves are *F* if and only if objects of
discursive cognition *as such* are *F*.


And the non-spatiality thesis as:



(C)
 [?] ~(Things in themselves are spatial)


But now the reader can see that to derive (C) from (1) we would need a
further premise:



(2)
 ~(Objects, considered, as objects of discursive cognition in
general, are spatial)


But this claim is not a definition, for it is equivalent to the claim
that the concept of a discursive cognition is more general than the
concept of a spatiotemporal discursive cognition, i.e., that a
non-spatial discursive intellect is conceivable. So although the
non-spatiality of things in themselves follows almost immediately from
*very general truths*, on Allison's reconstruction, it is
not correct to say that it is a tautology, or that it is true by
definition.



Nor is it true that the uncognizability of things in themselves is
trivial, on Allison's reading. For that principle only follows
from the claim that there are sensible epistemic conditions, space and
time. And that, on Allison's reconstruction, is the key insight
that sets Kant apart from both his rationalist and empiricist
predecessors. Thus, while Allison's interpretation makes the
argument for the non-spatiality of things in themselves relatively
*easy*, it does not render the conclusion trivial.


#### 4.3.2 Epistemic conditions entail realism



Robinson (1994) raises a quite general objection to Allison's
notion of an epistemic condition, namely, an object must satisfy (fall
under) a representation if that representation is to constitute an
epistemic condition for that object (Robinson 1994 is a response,
mainly, to Allison 1983 and 1987). So in the claim that "objects
*qua* appearances" or "objects *considered*
with our epistemic conditions" the qualification
"*qua* appearances" or "considered with our
epistemic conditions" is otiose. If space is an epistemic
condition of outer objects for us then this entails that objects we
cognize are in space *simpliciter*. The claim that objects are
spatial *because of* or *in virtue* of space being an
epistemic condition for them entails *either* that these
objects exist in virtue of our representations of them (which results
in phenomenalism) *or* it entails that they are spatial in
virtue of our representing them but would not be spatial otherwise. In
the latter case, we are not *cognizing* them in representing
them as spatial; we are *misrepresenting* them (Robinson 1994:
420-22).



Allison might reply to this objection by pointing out that it
implicitly assumes that the claim *empirical objects are in
space* is coherent independently of specifying a perspective on
those objects. In the terminology of Allison (2004) it is committed to
"transcendental realism" (see the supplementary entry:
 Allison on Transcendental Realism and Transcendental Idealism).
 If this were Allison's reply to the objection, then it would
show that the coherence of transcendental idealism, on Allison's
reconstruction, rests on the premise that there is no coherent sense
to questions about how objects are independent of any perspective on
them. This is important, because it is not always clear that
Allison's reconstruction does depend on this premise, and it is
not clear where Kant argues for such a conclusion.


#### 4.3.3 Abstraction



One influential objection focuses on the role that
"abstracting" from our spatiotemporal intuition plays in
Allison's reconstruction. Van Cleve puts it somewhat
facetiously:



> 
> 
> How is it possible for the properties of a thing to be vary according
> to how it is considered? As I sit typing these words, I have shoes on
> my feet. But consider me apart from my shoes: so considered, am I
> barefoot? I am inclined to say no; consider me how you will, I am not
> now barefoot. (Van Cleve 1999:
>  8)[46]
> 
> 
> 



To put the point less facetiously: if the object *o*,
considered as an object of spatiotemporal cognition, is spatial, then
when we ascend to a more general perspective, in which we consider
*o* as the object of discursive cognition in general, then we
should not say that *o* is *non-spatial*; we should
merely *not* judge that it is spatial. To take an example of
Guyer's, when we consider a job applicant we might want to
ignore or abstract from their race or sex; in doing so we would not
judge that they are race-less or sex-less, but merely refrain from
representing them as having a determinate race or sex.



Allison can interpret Kant's claim that things in themselves are
not spatial in either of two ways:



(1)
Things in themselves are non-spatial.
(2)
It is not the case that things in themselves are spatial.


While ordinarily we might take these claims to be equivalent, when
talking about "things in themselves" we can distinguish
them, because "things in themselves" talk is talk about
objects from a certain perspective (i.e., considered as objects of
discursive intellect in general). In particular, (1) and (2) are
equivalent to:



(1\*)
Objects, considered as objects of discursive cognition in general,
are non-spatial.
(2\*)
~(Objects, considered as objects of discursive cognition in
general, are spatial)


Allison's critics assume that he opts for (1) (and its analysis,
(1\*)) and object, rightly, that this is the wrong conclusion to draw
from the fact that discursive cognition is a more general notion than
spatiotemporal discursive cognition. (Just as it would be wrong to
conclude that the job candidate, considered in abstraction from his
sex and race, is sex-less and race-less.) While it is sometimes
unclear from Allison's texts which analysis he opts for, the
charitable reading is that he accepts (2\*).



If this is correct, Allison's reasoning can be reconstructed as
follows:



(3)
Things in themselves are *F* = objects, considered as objects
of discursive intellect in general, are *F*.
 (4)
It is conceivable that there is an object of discursive intellect
that is not an object of spatiotemporal discursive intellect, i.e.,
spatiotemporal discursive intellect is a special case of discursive
intellect.
 (5)
 [?] ~(objects, considered as objects of discursive intellect
in general, are spatial)
 (6)
 [?] ~(Things in themselves are spatial)


But (6) must be distinguished from:



(7)
 Things in themselves are non-spatial.


On this reconstruction of Allison, Kant is committed to (6) but not to
(7).



We saw earlier that Allison's critics assume that he must intend
(7) rather than (6). They do so because they think that it is clear
from the texts that Kant claims (7) and not the weaker (6). But that
is not so clear from the texts, for instance:



> 
> 
> Space represents no property at all of any things in themselves nor
> any relation of them each other, i.e., no determination of them that
> attaches to objects themselves and that would remain even if one were
> to abstract from all subjective conditions of intuition. (A26/B42)
> 
> 
> 



*Prima facie* it is compatible with the letter of these texts
that Kant is claiming (6) rather than (7). Note that (6) is not the
claim that we cannot know, or justifiably assert that things in
themselves are spatial. It is the claim that it is *false* to
say that they are *spatial*.



The stronger objection to Allison's view, as reconstructed here,
is that (6) is too weak to be a plausible reconstruction of
Kant's non-spatiality thesis. Given Allison's
understanding of "thing in itself" talk (premise (3)) all
that (6) requires is that there is some conceivable perspective on
objects that is more general than the specifically spatiotemporal form
of cognition that we have (premise (4)). It does not even require that
it is possible that there be discursive intellects with a
non-spatiotemporal form of cognition. All it requires is that the
concept of discursive cognition as such is more general than the
concept of spatiotemporal discursive cognition, which, trivially, it
is. (6) is compatible with it being impossible for there to be
non-spatiotemporal discursive cognition because all objects are
necessarily spatiotemporal and hence can only be cognized
spatiotemporally. In other words (6) is compatible with transcendental
realism about space and time (as Kant defines that term)!



One potential Allisonian response to this objection would be that it
implicitly presupposes that there is a way objects are independently
of any perspective on them. In particular, the claim that (6) is
compatible with all possible objects being spatial, and thus cannot be
a reconstruction of the non-spatiality thesis, begs the question by
assuming that that state-of-affairs does not need to relativized to a
perspective, e.g., all possible objects *as objects for a certain
kind of mind* are spatial. Thus, the coherence of Allison's
reconstruction again depends upon the claim that there is no
"standpoint-independent" perspective on reality.


#### 4.3.4 Things in themselves as more fundamental than appearances



One major textual hurdle for Allison's "epistemic"
reading of transcendental idealism is the various passages in which
Kant describes things in themselves as more fundamental, more
ontologically basic, than appearances, or describes things in
themselves as the *grounds* of appearances. Allison appears to
reverse this relation of dependence because things in themselves
(objects from the relatively abstract transcendental perspective) are
an abstraction from appearances (objects from the more determinate
empirical perspective). Ameriks (1992: 334) raises this objection, and
Allison (2004: 45) replies to it. Allison does not offer an alternate
reading of the relevant texts, but instead points out that, in the
case where the relative fundamentality of the phenomenal and noumenal
is most important to Kant, namely the freedom of the
 will,[47]
 Ameriks' objection assumes, once again, that there is some fact
of the matter as to whether we are free or not, and this is to be
settled by determining whether we are free at the most fundamental
level (the noumenal level, on Ameriks' reading). Once again, the
coherence of Allison's reading rests on the premise that there
is no standpoint-independent perspective on reality (see the
supplementary entry:
 Allison on Transcendental Realism and Transcendental Idealism).


### 4.4 Metaphysical "Dual Aspect" Readings



One prominent strand in recent scholarship on Kant's
transcendental idealism has been the development of quite
sophisticated interpretations that try to retain the original insight
that the appearance/thing in itself distinction is not a distinction
between two different kinds of objects, while abandoning Allison-style
"epistemic" readings. These interpretations take the
distinction to be a metaphysical one between two different sets of
properties had by one and the same set of objects. These metaphysical
"dual aspect" interpretations differ in exactly how they
understand the distinction between these different sets of properties
(see also Allais (2004, 2006, 2007, 2015); Rosefeldt (2007, 2013);
McDaniel (ms); and Marshall (2013)).



Perhaps the most influential metaphysical but non-phenomenalist
interpretation of Kant's idealism has been Langton (1998).
Langton begins by pointing out that Kant thinks we are genuinely
missing out on something in not knowing things in themselves, and this
sense of "epistemic loss" is incompatible with
Allison's reading. As we saw in the previous section,
"Allisonian humility" is apparently compatible with it
being impossible that there are non-spatiotemporal objects and our
forms of intuition being the *only possible* such forms. This
loses Kant's sense that we are genuinely cognitively deprived,
that there is something about the world of which we are irremediably
ignorant (Allison responds to Langton's criticism in 2004:
9-11).



Having rejected Allison's epistemic reading, Langton goes on to
discuss a familiar tension between two of the central doctrines of
Kant's transcendental idealism:



(*Existence*) Things in themselves exist.



(*Humility*) We cannot know anything about things in
themselves.



Langton's solution to this, one of the oldest problems of Kant
scholarship, is to interpret things in themselves as substances with
intrinsic properties, and talk of "phenomena" as talk of
the extrinsic properties of those substances (things in themselves).
So in general,



(1)
 Things in themselves are *F* = *F* is among the
intrinsic properties of substances
(2) 
 Appearances are *F* = *F* is among the extrinsic
properties of substances


In particular, this allows Langton to interpret (*Existence*)
and (*Humility*) as:



(*Existence*\*) Substances with intrinsic properties exist.



(*Humility\**) We cannot cognize the intrinsic properties of
substances.



The apparent tension between these doctrines has vanished.
Langton's interpretation also allows her to explain why the
apparent tension between *Humility* and



(*Non-spatiality*) Things in themselves are not spatial.



is merely apparent because, on her reading (Non-spatiality) is
equivalent to:



(*Non-spatiality*\*) Being spatial is not an intrinsic property
of substances.



This is compatible with (Humility\*) because we can know it merely by
knowing that being spatial is an extrinsic property in general (thus
is not an intrinsic property had by substances), and to know this we
do not need to know anything about the intrinsic properties of
substances. Langton thus offers a consistent, elegant interpretation
of transcendental idealism that solves several of the oldest and
hardest problems in the interpretation of Kant's
 philosophy.[48]


### 4.5 Problems for Langton's reading



Much of the critical reaction to Langton (1998) has focused on her
reconstruction of Kant's argument for Humility, but that will
not be discussed further here; even if Langton is wrong about how Kant
proves Humility, she may still be right about what Humility
*means* and thus what the appearance/thing in itself
distinction means (e.g., Allais 2006).


#### 4.5.1 Textual evidence



There is substantial textual evidence that Kantian appearances have
only extrinsic properties. For instance, this passage from the
"Aesthetic":



> 
> 
> everything in our cognition that belongs to intuition (with the
> exception, therefore, of the feeling of pleasure and displeasure and
> the will, which are not cognitions at all) contains nothing but mere
> relations, of places in one intuition (extension), alteration of
> places (motion), and laws in accordance with which this alteration is
> determined (moving forces). (B67)
> 
> 
> 



This, and other passages Langton cites, support attributing to Kant
these theses:



(1)
Appearances (phenomena) have only relational properties. (B67,
A265/B321, A285/B341)
 (2)
 When we conceive of an object purely intellectually we conceive
of it as having intrinsic properties. (A274/B330, A277/B333)
 (3)
 In knowing relational properties we do not know things as they
are in themselves. (B67)


However, in none of these passages does Kant directly state the
stronger claim that:



(4)
 Phenomena are extrinsic properties of substances with intrinsic
properties.


It is clear that Kant holds (1)-(3) and less clear that he holds
(4). The textual case for (4) is weaker, though not absent. It is
presented below, in
 sub-section 4.5.2.



There is a further textual problem for Langton's interpretation,
though. In at least two passages Kant denies that we can know
relations between things in themselves:



> 
> 
> Space represents no property at all of any things in themselves nor
> any relation of them each other [...] (A26/B42)
> 
> 
> 
> [...] the things that we intuit are not in themselves what we
> intuit them to be, nor are their relations so constituted in
> themselves as they appear to us. (A42/B59)
> 
> 
> 



In these passages Kant claims that space is not a relation among
things in themselves, nor are relations among objects "in
themselves" as they appear to us. This is hard to square with
Langton's reading. However, in her (2011) Langton responds to
these textual objections by suggesting that the relations among things
in themselves of which Kant speaks are *internal* relations,
relations that supervene on the intrinsic properties of
 substances.[49]


#### 4.5.2 *Phenomena substantiata*



One source of resistance to Langton's interpretation is that
Kant argues at length in the "First Analogy of Experience"
that the category *substance* can be applied to phenomena: 



> 
> 
> all appearances contain that which persists (substance) as the object
> itself, and that which can change as its mere determination, i.e., a
> way in which the object exists. (A182) 
> 
> 
> 



This would appear to contradict Langton's assertion that things
in themselves are substances, while appearances (phenomena) are merely
properties of substances.



Langton is well aware that Kant accepts "phenomenal
substances" and endeavors to explain this within her picture. In
doing so, she compiles a compelling set of textual evidence for her
alternative reading of the "First Analogy" and the meaning
of *substance* for phenomena. She begins by pointing to
Alexander Gottlieb Baumgarten's notion of a *phaenomena
substantiata*, a "substantiated phenomenon", by which
Baumgarten means a property that we treat as a substance by
predicating other properties of it (Baumgarten, *Metaphysica*
SS193 (Ak. 18:150); quoted at Langton 1998: 53). She argues
convincingly that Kant's fundamental notion of a substance is of
a being with properties but which is not a property of anything
 else.[50]
 Only such beings, of which other things are predicated (inhere in)
but which are not predicated of (inhere in) anything else, are truly
substances. However, the properties that are predicated of substances
can also be spoken of as substances, because they themselves have
properties (which might also have properties, and so
 on).[51]
 These are substantiated phenomena.



The question is, are Kantian empirical substances genuine substances
or mere substantiated phenomena? Do the objects subsumed under the
empirical schema of substance (absolute persistence in time) also fall
under the pure category of substance (subjects of inherence which
inhere in nothing further)? If not, then they must be predicated of
some more fundamental substance, which drives Langton to conclude that
appearances (phenomena) are properties of substances (she does point
out the hesitant terms in which Kant describes phenomena as substances
(1998, 57). Langton assembles an impressive array of evidence that
Kant does regard empirical "substances" as *phaenomena
substantiata* (e.g., A265/B321, A277/B333, Refl. 4421, 4422, 5294,
Ak. 28:209). However, in context it is not clear whether Kant has the
Baumgarten notion in mind, or whether this Latin expression means
simply: phenomenal substance. So it is unclear, textually, whether
phenomena are predicated of noumena in the
 *Critique*.[52]



In his metaphysics lectures, and other texts, Kant consistently
distinguishes the inherence relation (which holds between a property
and an entity of which it is predicated) from the relation of
*ground* to *consequence*:



> 
> 
> The world "substance" is clearly ambiguous. One translates
> it through the notion of self-sufficiency, i.e., the possibility of
> existing without a ground, but also as the possibility of existing
> without inhering [in something else]. (Ak. 28:1308; Ak. 8:225n,
> 28:562, 28:779, 28:638-9, 28:1041, 28:1104f)
> 
> 
> 



Kant, following Baumgarten, criticizes Spinoza's definition of
substance as "what is in itself and conceived through
itself" (*Ethics* Id3) because it conflates two notions:
(i) a being that is not grounded in, or caused by, anything more
fundamental, and (ii) a being that does not inhere in anything more
fundamental. The second is the correct definition of substance,
according to Kant; by conflating these two notions, Spinoza forecloses
the following possibility: there are substances distinct from God
(they are not modes of God), all of which are grounded in God.



To bring this back to Langton, we need to distinguish two different
claims:



(i) 
 Phenomena are extrinsic properties of substances (things in
themselves). They inhere in things in themselves.
(ii) 
 Phenomena exist (at least partly) in virtue of the extrinsic
properties of substances (things in themselves). They are grounded in
things in themselves.


Langton attributes (i) to Kant, but her textual case appears to
support (ii), at
 best.[53]
 This is significant, because (ii) is far less controversial. For
instance, it is in principle acceptable to the qualified
phenomenalist, because the extrinsic properties of things in
themselves include (presumably) properties like *causing us to have
such and such experience*.


## 5. One Object or Two?



Since Karl Ameriks' classic survey of the literature, Ameriks
(1982), it has been customary to divide interpretations of
transcendental idealism into "two object" readings and
"one object" readings. By contrast, this article has been
organized around the distinction between phenomenalist readings, and
non-phenomenalist dual-aspect readings. This section explores the
relation between the "one object"/"two object"
distinction and the phenomenalist/non-phenomenalist distinction among
different interpretations of Kant's idealism.



The distinction between "one object" and "two
object" readings comes down to the question of whether
appearances, in general, are numerically identical to things in
themselves: "one object" readers claim they are (Adickes
1924: 20, 27; Allais 2004: 657; Langton 1998: 13; Westphal 1968: 120),
and "two object" readers deny
 this.[54]
 Whether all things in themselves are numerically identical to
appearances is not at issue, for most one object readers will admit
there could be things that never appear to us (cf. B306, where Kant
seems to admit as much) (although it might be misleading to call them
things "in themselves" since they never appear to us, so
we never consider them as they are "in themselves"). The
qualification "in general" is necessary because some
"two object" readers will admit that some appearances are
also things in themselves; e.g., many "two object" readers
will admit that, in the case of the self, there is a single object, a
thing in itself, that appears to itself as a spatiotemporal object (on
this issue, see Adams (1997), Aquila (1979), and Ameriks'
discussion of Aquila in his 1982).



However, the characterization of these views as "one
object" and "two object" is unfortunate, because it
is not a commitment of "two object" readings that, for
each appearance, there is one and only one thing in itself that
appears as that object. The "two object" interpreter can
hold that each appearance is the appearance of an indefinite plurality
of things in themselves. Nor is the other standard moniker, "one
world" versus "two world", helpful, either, for
"world" is a technical term in Kant's metaphysics
and has a very specific
 meaning.[55]
 One can coherently hold a "non-identity" interpretation
while denying that appearances in space and time constitute a
"world" at
 all.[56]



This section explores how the identity/non-identity debate relates to
the non-phenomenalist/phenomenalist debate. They have often been
conflated by equating the "two world" interpretation
(non-identity) with the phenomenalist one, and conversely, by equating
the "one world" interpretation (identity) with the
anti-phenomenalist one. There are grounds to think, however, that
these are distinct debates.
 Section 5.1
 examines whether claims about the numerical identity or non-identity
of appearances and things in themselves are meaningful at all, and, if
they are, what warrant we could have for making them within
Kant's theoretical philosophy.
 Section 5.2
 looks at whether paradigmatically anti-phenomenalist interpretations
(e.g., Langton 1998) can be understood as non-identity views.
 Section 5.3
 examines some reasons for thinking that the phenomenalist
interpretation is compatible with the "identity" of
appearances and things in themselves.
 Section 5.4
 considers the interpretive landscape in light of these
 results.[57]


### 5.1 Identity between appearances and things in themselves



As Henry Allison and others have pointed out, it is not clear that
there is any content to the question of whether an appearance is
numerically identical to a thing in itself, outside of moral
 contexts.[58]
 It is relatively clear that in the context of his moral philosophy,
Kant wants to assert that one and the same object, a rational agent,
can be considered as an appearance and as a thing in itself.
Considered as an appearance, a rational agent is subject to conditions
of experience (space, time, and the categories). Considered as a thing
in itself, a rational agent can at least consistently be thought of as
free (because independent of the deterministic causal order of space
and time), while practical reason gives us warrant for positively
asserting that the agent is free. Kant typically expresses this
solution to the problem of freedom and determinism in terms of the
numerical identity of the appearance of the agent and the agent as
thing in itself (e.g., Ak. 5: 105, 114). Practical reason gives both
content and warrant to the assertion of numerical identity:
*content*, because the assertion of numerical identity means
that one and the same noumenal agent is the cause of and therefore
*responsible for* the actions of an empirical rational agent
over time, and *warrant*, because this assumption of the unity
of a noumenal agent over time is a presupposition of our ordinary
moral cognition of blame and praise. But neither of these seem to hold
in the theoretical use of reason. It is not clear that within the
theoretical use of reason we can give any *content* to the
claim of the numerical identity (or distinctness) of appearances and
things in themselves, nor any warrant for asserting or denying
 it.[59]



In defense of the contentfulness of these identity claims, one might
argue that the term "appearance" and "thing in
itself" each has an extension, a set of objects, and the
question of identity is perfectly well-formed: do these two sets have
a non-empty intersection? If so, at least one appearance is identical
to a thing in itself. But this argument begs the question by assuming
that the question of whether the set of appearances and the set of
thing in themselves has an intersection is itself well-formed; whether
this is the case is precisely what is at issue.



While many interpreters (notably Adams 1997: 822) think that we can
have no warrant for asserting the identity or non-identity of
appearances and things in themselves in general, and thus think the
identity/non-identity debate (at least in theoretical contexts)
concerns something about which Kant must be agnostic, there are those
who disagree (Stang 2014; cf. Walker 2010). In texts quoted earlier,
Kant claims that appearances would cease to exist if there were not
minds to experience them. On the assumption that this is not true of
things in themselves, consider the following argument:



(P1) 
 For any *x*, if *x* is an appearance, *x*
would not exist if there were no minds to experience it.
 (P2) 
 For any *x*, if *x* is a thing in itself,
*x* would exist if there were no minds to experience it.
 (C) 
 For any *x*, if *x* is an appearance, *x* is
not a thing in itself.


This argument purports to show that, since appearances and things in
themselves have different modal properties, they must be distinct.
Since (P1) and (P2) are claims Kant makes in the context of his
theoretical philosophy, this argument provides warrant for denying
identity on purely theoretical grounds.


### 5.2 Langton and non-identity



Langton's view can be interpreted as either an identity reading
or a non-identity reading. The difference is somewhat subtle, but it
has important consequences. On the identity version of Langton (1998),
to talk about things in themselves is to predicate intrinsic
properties of substances, while to talk about phenomena is to
predicate extrinsic properties of *those very substances*. On
the non-identity version of Langton (1998), phenomena are numerically
identical to those extrinsic properties. This would be a non-identity
reading because substances are not identical to their properties
(either extrinsic or intrinsic). By contrast, on the identity reading,
an expression for a phenomenon *refers* to a substance. The
difference between these readings can be illustrated by how they give
truth-conditions for the judgment that some phenomenon *x* has
property *F*:



(*Identity*) *x* has *F* = *F* is among
the extrinsic properties of *x*



(*Non-Identity*) *x* has *F* = *x*, an
extrinsic property of some substance *y* ([?]*x*), has
*F*



While Langton initially explains her view in a way that suggests an
identity reading, she in fact opts for a non-identity reading, for
good reason. Firstly, on the identity reading Kant would have to
identify subjects of predication in empirical judgments with
substances. This is problematic because it would bring substances into
the world of space and time. For instance, if I can make a judgment
about this table, then it would be a judgment about the extrinsic
properties of this table, and this table would be a substance with
intrinsic properties (although being a table would, presumably, not be
one of them). Alternately, if we identify the table as a collection of
extrinsic properties of substances, then we can go on to predicate
further properties of the table, without having to identify the
substance or substances of which the table is ultimately
 predicated.[60]


### 5.3 Phenomenalist Dual Aspect Readings



Some scholars have defended what might initially seem like a
contradiction in terms: a phenomenalist "one object"
(identity) interpretation of appearances and things in
 themselves.[61]
 On such a view, the appearance and the thing in itself are one and
the same object, but considered with respect to different properties:
the properties we experience the object as having, and the properties
it has. On this interpretation, Kant is qualified phenomenalist
because he holds that:



(*PhenomenalismP*) The core physical properties of
objects in space are grounded in the contents of our experience of
them.



His attitude to:



(*PhenomenalismE*) The existence of objects in space
is ground partly or wholly in the contents of our experience of
them.



depends upon how we read it, on this interpretation. On the one hand,
we can understand it either as the "*de re*"
claim



(*Phenomenalism*E\*) (*x*)(*x* is an
object in space [?] the existence of *x* is partly or wholly
grounded in our experience of *x*)



in which case Kant would reject it, because each such object in space
is also a thing in itself and, as such, does not depend for its
existence on our experience of it. On the other hand, we could
understand it as the *de dicto* claim



(*Phenomenalism*E\*\*) The fact that there are objects
in space is partly or wholly grounded in our experience of objects in
space.



in which case Kant would accept it, because there being objects in
space depends upon our experiencing objects as in space.



This leads to an important exegetical point. One of the main
motivations for "non-identity" interpretations are
passages in which Kant claims that appearances would not exist if
there were not subjects to experience them, e.g., A42/B59. This might
be thought to directly entail phenomenalism, for, if appearances would
not exist without subjects to experience them, but things in
themselves would, then *a fortiori* appearances and things in
themselves are distinct. This line of reasoning can be represented
formally as (P1), (P2) and C from section 5.1. But the identity reader
can interpret Kant's claim "if I were to take away the
thinking subject, the whole corporeal world would have to
disappear" as meaning: without subjects to experience them,
appearances would not exist *as appearances*, i.e., would not
appear. In other words, she can reinterpret (P1) as:



(P1\*)
 For all *x*, if *x* is an appearance, then
*x*'s existence *as an appearance* (=the fact that
*x* exists and appears) is grounded in the contents of
experience.


But the conjunction of this and (P2) does not entail (C); they are
compatible with the identity reading. These passages do not
*force* the non-identity interpretation on us. (For more on
phenomenalist identity readings see the supplementary article:
 Phenomenalist Identity Readings and the Problem of Illusion.)


### 5.4 Assessing the Interpretive Issues



We have seen some reasons to think that the resolutely
anti-phenomenalist reading of Langton (1998) and the phenomenalist
reading can be re-interpreted as, respectively, a non-identity reading
and an identity reading. One reaction would be to conclude that the
interpretive options are simply more complex than is usually
appreciated:





|  |  |  |
| --- | --- | --- |
|  | **Non-Identity** | **Identity** |
| **Epistemic** | **Metaphysical** |
| **Phenomenalist** | Aquila (1983), Van Cleve (1999), cf. section 3  | N/A  | Adickes (1924), Westphal (1968)  |
| **Anti-phenomenalist** | Alternate version of Langton  | Allison (1983/2004), Bird (1962), Prauss (1974)  | Langton (1998), Allais (2006)  |



Table 1




But the distinction between the two different versions of Langton, and
between the non-identity version of phenomenalism (Aquila 1983; Van
Cleve 1999) and the identity version of phenomenalism (Adickes 1924;
Westphal 1968) is relatively recondite. It depends on the
controversial assumption that assertions of identity between
appearances and things in themselves, outside of practical contexts,
have a content.



Furthermore, Henry Allison has recently argued that even his view is
neutral on the identity/non-identity debate:



> 
> 
> although it is sometimes assumed that [the two-aspect reading] commits
> Kant to a highly implausible one-to-one mapping of the phenomenal and
> noumenal, I take that to be a red herring. First, it is one thing to
> distinguish between things (taken collectively) as they are for us in
> virtue of the sensible conditions of human cognition and as they might
> be for some putative pure understanding, unburdened by such
> conditions, and quite another to affirm a one-to-one correspondence or
> isomorphism between the members of the two domains. (Allison 2004: 459
> note 19; cf. Allison 1987: 168)
> 
> 
> 



Allison's idea is that the distinction between the empirical and
the transcendental standpoint is a distinction between how they
consider objects *as a whole*, not how they consider particular
objects. The Epistemic reading is not committed to Identity, but
neither is it committed to Non-Identity. So an Identity version of the
Epistemic reading is possible (according to which we can consider each
object individually from either standpoint), as is an Epistemic
reading that is neither an Identity nor a Non-Identity reading (on
which we remain agnostic as to whether objects considered from one
standpoint are numerically identical to objects considered from
 another).[62]
 So we might conclude that our interpretive options are even more
numerous than we initially thought:





|  |  |  |  |
| --- | --- | --- | --- |
|  | **Neither Identity nor Non-Identity** | **Non-Identity** | **Identity** |
| **Epistemic** | **Metaphysical** |
| **Phenomenalist** | N/A  | Aquila (1983), Van Cleve (1999), cf. section 3  | N/A  | Adickes (1924), Westphal (1968)  |
| **Anti-phenomenalist** | Allison (1983/2004) | Alternate version of Langton  | Bird (1962), Prauss (1974), alternate version of Allison
(1983/2004),  | Langton (1998), Allais (2006)  |



Table 2




But notice we now have doubling of interpretations: identity and
non-identity versions of Langton (1998), identity and non-identity
versions of phenomenalist views, and identity and "neither
identity nor non-identity" versions of Allison.



However, if one thinks that claims of identity between appearances and
things in themselves are contentless (see section 5.1), at least
outside of the context of practical philosophy, then the menu of
interpretive options will appear as:





|  |  |
| --- | --- |
| **Phenomenalist** | **Anti-Phenomenalist** |
| **Epistemic** | **Metaphysical** |
| Aquila (1983), Van Cleve (1999), Adickes (1924), Westphal
(1968), cf. section 3  | Allison (1983/2004), Bird (1962), Prauss (1974)  | Langton (1998), Allais (2006)  |



Table 3




On such a reading, there is no substance, outside of the practical
context, to the question of whether an appearance is *numerically
identical* to a thing in itself, so the identity and non-identity
versions of, e.g., phenomenalism, are
 equivalent.[63]
 If one holds instead that these identity claims have a content but
that we cannot know them on theoretical grounds alone (see section
5.1) then one will likewise see these interpretive options as so
constrained, because, although there is a difference in content
between, say, the identity and non-identity versions of phenomenalism,
Kant must be agnostic as to which is true.


## 6. Things in themselves, *noumena*, and the transcendental object



Up to this point, we have focused primarily on the nature of Kantian
appearances, and their relation to things in themselves, questions (a)
and (c) from section one. However, one of the main questions that must
be answered in any interpretation of Kant's transcendental
idealism is, what are things in themselves? Obviously, different
interpretations will give very different answers to this question:



*Phenomenalist interpretations*. Perhaps the best statement of
the phenomenalist interpretation of things in themselves is given by
Erich Adickes (1924: 14-19): things in themselves are a
plurality of mind-independent centers of force. On this view, things
in themselves are just what we pre-theoretically took ordinary
spatiotemporal objects to be: objects that exist, and possess their
core physical properties, wholly independently of our representations
of them, and which are (among) the causal inputs to our perceptual
faculties (a variant of this thought is expressed by Ameriks 2003:
23-25).



*Epistemic interpretations*: On the epistemic reading, things
in themselves are simply objects considered independently of our
distinctively spatiotemporal form of intuition. Thus, they are objects
considered as objects of a discursive cognition in general. This very
abstract thought is not the basis of any cognition, however; it is
merely a reminder that space and time are epistemic conditions,
without which we cannot cognize any object.



*Metaphysical "dual aspect" interpretations*. On
this family of interpretations, things in themselves are objects with
a given set of properties. Different interpretations give a different
answer as to which set of properties constitute things "as they
are in themselves". On Langton's reading, for instance,
things in themselves are substances with intrinsic properties.



In this section we distinguish "things in themselves" from
other, closely related Kantian notions: *noumena*, and the
"transcendental object".


### 6.1 *Phenomena* and *noumena*



In the section "On the ground of the distinction of all objects
into *phenomena* and *noumena*", which he
substantially revised for the B Edition, Kant reiterates his argument
that we cannot cognize objects beyond the bounds of possible
experience, and introduces a complex distinction between phenomena and
noumena.



Fortunately, it is relatively clear what phenomena are:
"appearances to the extent that as objects they are thought in
accordance with the unity of the categories are called
phenomena" (A249). Earlier, in the "Aesthetic", Kant
had defined appearance as: "the undetermined object of an
empirical intuition" (A20/B34). All objects of empirical
intuition are appearances, but only those that are "thought in
accordance with the unity of the categories" are phenomena. For
instance, if I have a visual after-image or highly disunified visual
hallucination, that perception may not represent its object as
standing in cause-effect relations, or being an alteration in an
absolutely permanent substance. These would be appearances but not
phenomena. The objects of "universal experience", as
defined in section 3, are phenomena because the categories determine
the *a priori* conceptual form; universal experience represents
its objects under the unity of the categories.



Kant's then introduces the concept of noumena:



> 
> 
> if, however, I suppose that there be things that are merely objects of
> the understanding and that, nevertheless, can be given to an
> intuition, although not to sensible intuition (as *coram intuiti
> intellectuali*), then such things would be called noumena
> (*intelligibilia*). (A249)
> 
> 
> 



The concept of a noumenon, as defined here, is the concept of an
object of cognition for an intellect that is not, like ours,
discursive, and thus has a non-sensible form of intuition, which Kant
here designates "intellectual
 intuition".[64]
 A sensible intuition is one that can only intuit objects by being
causally affected by them; a non-sensible intuition is one in which
the intuition of the object brings the object into existence. Thus,
the concept of a noumenon is the concept of an object that would be
cognized by an intellect whose intuition brings its very objects into
existence. Clearly, we do not cognize any noumena, since to cognize an
object for us requires intuition and our intuition is sensible, not
intellectual.



Kant then connects the concept of noumena to things in themselves:




> 
> 
> it also follows naturally from the concept of an appearance in general
> that something must correspond to it which is not in itself
> appearance, for appearance can be nothing for itself and outside of
> our kind of representation; thus, if there is not to be a constant
> circle, the word "appearance" must already indicate a relation to
> something the immediate representation of which is, to be sure,
> sensible, but which in itself, without this constitution of our
> sensibility (on which the form of our intuition is grounded), must be
> something, i.e., an object independent of sensibility. Now from this
> arises the concept of a *noumenon*, which, however, is not at
> all positive and does not signify a determinate cognition of something
> in general, in which I abstract from all form of sensible intuition.
> (A251-2)
> 
> 
> 



This passage begins with the familiar point that the very concept of
appearance requires that there be something that is not appearance
that appears. Usually Kant makes this point using the concept
"things in themselves" (e.g., in the *Prolegomena*
(Ak. 4:314-5); cf. Bxxvi-xxvii, B306, and B307). However,
here he claims that this idea--that it cannot be
"appearances all the way down"--brings with it the
idea of noumena. This is puzzling. Why must whatever it is that appear
to us as phenomena be conceived of as an objects of intellectual
intuition?



Kant clarifies precisely this point in the B Edition by distinguishing
between a positive and a negative sense of "noumena": 



> 
> 
> If by a noumenon we understand a thing **insofar as it is not an
> object of our sensible intuition**, because we abstract from
> the manner of our intuition of then this is a noumenon in the
> **negative** sense. But if we understand by that an
> **object of a non-sensible intuition** then we assume a
> special kind of intuition, namely intellectual intuition, which,
> however, is not our own, and the possibility of which we cannot
> understand, and this would be the noumenon in a
> **positive** sense. (B307)
> 
> 
> 



Noumena in a positive sense are simply noumena as Kant originally
defined that notion in the A edition: objects of an intellectual
(non-sensible) intuition. The negative concept of noumena, however, is
simply the concept of objects that are not spatiotemporal (not objects
of our sensible intuition, namely space and time). But then it follows
that things in themselves are noumena in the negative sense,
retrospectively clarifying the passage from the A edition quoted
immediately above, where Kant seems to draw from the
"Transcendental Aesthetic" the conclusion that there are
noumena: the concept of appearance requires that something appears,
and this must be a negative noumena.



Putting these pieces together we can see that "things in
themselves" [*Dinge an sich selbst*] and (negative)
"noumena" are concepts that belong to two different
distinctions: "thing in itself" is one half of the
appearance/thing in itself distinction, which Kant originally defined
at A491/B519 in terms of their existence: appearances have no
existence "grounded in themselves" while things in
themselves do. "Noumena" is one half of the distinction
phenomena/noumena which Kant characterizes at B307 as the distinction
between what can be an object of our sensible spatiotemporal intuition
and what cannot be an object of sensible intuition. (Kant here appears
to overlook the possibility of objects of sensible but
non-spatiotemporal intuition). One is a distinction in what ground the
existence of objects; the other is a distinction in what kinds of
intuition can present those objects. However, we can make a connection
between them: things in themselves, the objects whose existence is
"ground in itself", and which appear to us in space and
time, cannot be objects of any sensible intuition, so they are
negative noumena. Whether, additionally, they are also objects of an
intuitive intellect, is a separate matter. This is a point about the
relations among these concepts; it holds whether or not they are
possibly instantiated.


### 6.2 The transcendental object = *X*



In the "Phenomena and noumena" section, Kant distinguishes
the concept of a noumenon from the concept of a "transcendental
object" (A250). This is a reference to a notion introduced in
the A version of the "Transcendental Deduction": 



> 
> 
> The pure concept of the transcendental object (which in all of our
> cognition is really one and the same = *X*) is that which in all
> of our empirical concepts in general can provide relation to an
> object, i.e., objective reality. Now this concept cannot contains any
> determinate intuition at all, and therefore contains nothing but that
> unity which must be encountered in a manifold of cognition insofar as
> it stands in relation to an object. (A109; cf. A104)
> 
> 
> 



The "concept of a transcendental object" might be
fruitfully thought of as "the transcendental concept of an
object": the concept of "object" that makes
experience possible. Our mind's synthesis of representations
into experience of objects is guided and made possible by the idea
that there is a way objects are that must be tracked by our
representations of them. This wholly abstract concept of "a way
things are" is the concept of the transcendental object =
*X*, the indeterminate concept of the "target" of our
representational activity. Consequently, the concept of the
transcendental object must be distinct from the concept of
"things in themselves" or "negative noumena".
The concept of things in themselves is the concept of the (unknowable
by us) objects (or aspects of objects) that appear to us the 3D world
of space and time. They are the grounds of phenomena, while the
transcendental object is the very abstract idea of those objects in
space and time as the targets of our cognitive activity.



Another way to appreciate this distinction is to consider the
difference in why these notions of object (noumena, transcendental
object) are unknowable by us. We cannot cognize things in themselves
because cognition requires intuition, and our intuition only ever
presents appearances, not things in themselves. We cannot cognize the
transcendental object because the transcendental object is a purely
schematic, general idea of empirical objectivity. Whenever we cognize
a determinate empirical object we are cognitively deploying the
transcendental concept of an object in general, but we are not coming
to know anything about the object of that concept as such.



This is Kant's point in "phenomena and noumena" when
he writes: 



> 
> 
> This transcendental object cannot even be separated from the sensible
> *data*, for then nothing would remain through which it would be
> thought. It is therefore no object of cognition in itself, but only
> the representation of appearances under the concept of an object in
> general, which is determinable through the manifold of those
> appearances. (A250-1) 
> 
> 
> 



The (negative) concept of a noumenon is the concept of an object that
is not an object of our sensible spatiotemporal intuition. But the
transcendental object makes no sense in abstraction from intuition,
because it is merely the abstract concept that the unity of our
intuitions must have in order to constitute experience of an object
(cf. Allison's classic 1968 paper).


## 7. Conclusion



This article has traced the meaning of transcendental idealism,
sometimes referred to as "critical" or
"formal" idealism, through the text of the *Critique of
Pure Reason* and various interpretive controversies. Historically,
the main question dividing different interpretations is whether Kant
is a phenomenalist about object in space and time and, if so, in what
sense. The phenomenalist interpretation of Kant, dominant among
Kant's immediate predecessors and later German idealists, was
challenged in twentieth century Anglophone scholarship by, among
others, Graham Bird, Gerold Prauss, and Henry Allison. Some later
scholars have retained a central idea of these scholars'
reading--that the appearance/thing in itself distinction is a
distinction between distinct aspects of objects, not distinct kinds of
objects--while jettisoning the purely epistemological
interpretation of Kant's idealism. The meaning and philosophical
significance of "transcendental idealism" has been debated
by Kant's readers since 1781, and this debate shows no sign of
abating any time soon.