1 Introduction
Immanuel Kant’s Critique of Pure Reason contains many
sections and concepts that still produce lively contemporary debate. One
of the most energetic of these is regarding Kant’s position on idealism.
Idealism is commonly understood in modern philosophy to mean either that
the ultimate foundation of reality is the mind, nothing exists beyond
the mental, or that something does exist independently of the mind.
However, our knowledge of the mind-independent reality, at best, can
only be inferred and, at worst, is entirely inaccessible (Guyer and Horstmann 2022,
sec. 1). Whilst Kant’s idealism is certainly related to these two
formulations, we shall see how it differs, is very much its concept and
how the two major interpretations of Kant’s idealism see it.
We will find it useful to define some terminology used frequently
throughout this essay. It will be vital to note the Kantian meaning of
these terms as it is often somewhat different to the meaning in common
contemporary language. First, we shall define transcendental; this is
knowledge “that concerns the a priori possibility of knowledge, or its a
priori employment” (Kant, 1781&1787/2011, A56/B81). We find the
rest of these key terms within the first part of the Critique of
Pure Reason, within the transcendental aesthetic. We must define
intuition, this is the seeing of some object (Kant, 1781&1787/2011,
A19). For Kant, this is made possible by sensibility, this is
the capacity for sensing things in a given modality (Kant, 1781&1787/2011,
A19). Intuitions gained from our sensibility yield concepts
through our understanding. Concepts are purely thought but can only
exist in relation to intuition. Appearence is a thing as seen
in intuition only (Kant, 1781&1787/2011, A20/B34). Naturally,
we are only capable of intuitions that our sensibility is capable of.
Kant determines the most underlying and a priori aspect of our
sensibility, the way that our minds cannot help but order the world as
it is fundamental to our cognition is space and time (Kant, 1781&1787/2011,
A22). This is important to note as space and time in the Kantian view
are not things that exist in themselves. The following quotation further
illuminates this, “time is the formal a priori condition of all
appearances whatsoever. Space, as the pure form of all outer
intuition” (Kant, 1781&1787/2011, A34). It will be
crucial to our later discussion to clarify the function of space and
time for Kant, i.e., our a priori sensibility, what Kant terms the
transcendental aesthetic, that conditions our experience of
reality.
Additionally, we will find it helpful to have a brief introduction to
the two significant camps of interpretation of Kant’s position on
idealism. We shall use the terminology of Henry Allison, the first of
the two camps, Allison’s own; he terms ‘two-aspect’ (Allison 2004, 3).
Briefly, as this will be expanded in later sections, the ‘two-aspect’
interpretation is taking Kant’s position to be that external things
exist and are given in the appearance. They are considered in two
separate non-ontological ways, as they appear and as they are in
themselves (Allison
2004, 12). The second of the two interpretive camps is termed
‘two-world’ (Allison
2004, 3) in which there is an appearance of an object that is
available to our sensibility termed the phenomenon. There is also an
object that is ‘the thing in itself’ termed the noumenon, that we do not
have direct access to in our sensibility and from which we can only
infer the existence. We cannot know about the intrinsic properties of
the noumenon, only the phenomenon. Now armed with the Kantian
terminology and basic knowledge of the two interpretive camps, we can
now attend the structure of our investigation into Kant’s position on
idealism.
In the first section of this essay, we shall examine how Kant views
idealism, with a specific interest in Descartes’ and Berkeley’s
conceptions of idealism, termed sceptical idealism and dogmatic
idealism, respectively. We shall see what problems Kant believes these
two forms of idealism possess. Following this, we shall follow Kant’s
argumentation for his refutation of sceptical and dogmatic idealism and
how this refutation fits into the Kantian picture.
In the second section, we shall continue examining Kant’s evidence for
the success of his new system, which he terms transcendental idealism.
Kant does this in his fourth paralogism, and we shall take particular
note of how Kant uses his new concept of transcendental idealism to
critique Descartes. In this section, we shall see what Kant sees the
problem of Descartes’ system to be and how this has motivated Kant’s
position on idealism.
In the third section, we shall look closely at the position Kant has
developed. We will look at the arguments given by both significant sides
of the interpretation dispute regarding transcendental idealism. To do
this, we shall see what problems transcendental idealism has solved and
which new problems it raises under the two major interpretations of
transcendental idealism. Although contributing to the resolution of this
debate is far beyond the scope of this essay, I hope to be able to
determine my position and justify my interpretation of Kant’s position
on idealism concerning the major interpretations and the Critique of
Pure Reason itself.
Finally, we shall examine a modern debate in science, namely how we
should interpret the meaning of quantum physics. We shall look at two
types of interpretation and justify why Kant himself may favour one
interpretation over the other in the context of Kant’s form of
idealism.
2 Kant’s refutation of idealism
In this first section, we will initially examine what Kant thinks of
idealism, specifically regarding the two types of idealism that Kant
identifies, namely sceptical and dogmatic idealism. We shall see what
issues Kant believes both species of idealism suffer from and how he
aims to refute them simultaneously with a single proof.
Kant begins his discussion on the refutation of idealism by specifying
the exact theories of idealism he aims to refute. He defines
problematic idealism as the theory proposed by Descartes; we
shall term this in a more contemporary manner as sceptical
idealism. Kant defines this as “the theory which declares the
existence of objects in space outside us [...] to be merely doubtful and
indemonstrable” (Kant, 1781&1787/2011, B274). Essentially we
can never know for certain that the external world exists or is how we
perceive it to be. Kant then distinguishes Descartes’ idealism from
Berkeley’s, termed dogmatic idealism. Dogmatic idealism
maintains that external objects in space is “false and impossible”
(Kant, 1781&1787/2011, B274). Dogmatic
idealism regards space itself as impossible; therefore, all objects
which are contingent on space equally impossible. Kant argues the
dogmatic position to be a consequence of believing that space is a
property that belongs to things in themselves as Kant states that in
this case, space is a “non-entity” (Kant, 1781&1787/2011, B274). Therefore,
Kant believes that the key to undermining dogmatic realism has already
been discussed within the transcendental aesthetic (Kant, 1781&1787/2011,
B274). For Kant, space is not within things or a thing in itself; it is
part of our a priori sensibility. It is the fundamental way in which our
cognition conditions our experience. We can already see the innate
tension between dogmatic idealism and Kant’s system.
Before Kant begins his refutation of sceptical and dogmatic idealism, he
outlines what is required of a proof. Kant must show that we possess
experience of external things. To do this, he adheres to Descartes’
primacy and infallibility of the existence of inner experience. Kant
must show that inner experience depends on the existence of outer
experience (Kant, 1781&1787/2011, B275). With the
dependence of inner experience on outer experience, our condition for a
successful refutation, Kant begins his proof.
Kant states that we are conscious of our existence, determined through
our a priori sensibility of time (Kant, 1781&1787/2011, B275). He argues that
there is a ‘permanent’ in perception; otherwise, determination of time
is impossible. As Kant is determining his own conscious existence in
time, the perception of the permanent is only possible through a thing
outer to oneself (Kant, 1781&1787/2011, B275). Essentially
consciousness of our own experience in time requires the determination
of that time, which is only possible by something external that is
permanent (in some manner) so that measurement (determination) of time
can be achieved. Being conscious of our existence requires the immediate
consciousness of external things to oneself (Kant, 1781&1787/2011,
B276). Kant has used his transcendental aesthetic, i.e., the a priori
sensibility of time, a fundamental conditioner of our experience, in
combination with the existence of our immediate inner experience to
prove the existence of our outer experience.
We can see how Kant has used the transcendental aesthetic to refute both
sceptical and dogmatic idealism. Sceptical idealism forms the weak
conviction that we cannot be certain of the existence of external
experience, whereas dogmatic idealism believes space does not exist and
be therefore imaginary. Kant has used the a priori sensibility of time,
the sensibility that dogmatic idealists do not dispute, and the shared
belief of both forms of idealism in the primacy of immediate inner
experience.
Kant has used his Copernican turn to show that space and time condition
experience and that our a priori sensibility is essential for knowledge
(Braver 2007,
36–37). By reformulating our subject-object relationship, Kant
has shown the creation of a system capable of refuting classical
idealism as a mere consequence of his system.
The following section will explore the fourth paralogism and Kant’s
critique of Descartes. Here, we will begin to flesh out Kant’s
transcendental idealism and what he believes its justifications and
implications are.
3 The fourth paralogism
In the fourth paralogism, Kant critiques sceptical idealism and
Descartes more thoroughly, identifying problems with this theory and
using these problems to motivate the formulation of Kant’s
transcendental idealism. Kant will attempt, much as he does throughout
the Critique of Pure Reason to put natural science on a
justifiable basis and expose the underlying assumptions that made for an
incoherent metaphysics prior to Kant.
Descartes is initially praised in the fourth paralogism, for Kant
believes that Descartes was correct in limiting all perception to
immediate perceptions of the inner sense (Kant, 1781&1787/2011, A368). However, the
inference then required by the sceptical idealist is too much for Kant,
especially as we have seen in Kant’s refutation of idealism. Kant
believes that the determination of the inner sense requires the
existence of perceptions in the outer sense. Therefore, Descartes has
identified something true, namely all perceptions genuinely being in the
inner sense, but has drawn a troubling conclusion for Kant about the
doubtful existence of the outer world (Kant, 1781&1787/2011, A366-A367). Knowing
how Kant refutes idealism from section 2, we shall
see in this section how Kant broadens his system and its implications
for metaphysics and knowledge.
We shall define Kant’s system, transcendental idealism from his writing
in the fourth paralogism and the differences that Kant’s idealism has in
regards to Descartes’ sceptical idealism, which Kant identifies as
empirical idealism (Kant, 1781&1787/2011, A369). Kant’s
transcendental idealism regards the appearances of objects as the whole
‘thing’ of the object. There is no thing in itself beyond
representations and that space and time themselves are only sensible
forms of our intuition (Kant, 1781&1787/2011, A369). This is in
opposition to transcendental realism, the doctrine that space and time
and objects that exist in space and time are something in and of
themselves that is independent of our sensibility (Kant, 1781&1787/2011,
A369). Descartes and almost all philosophers prior to Kant are
transcendental realists (Braver 2007, 33–34), Kant argues
that transcendental realism is what opens the door for idealism, or as
Kant wishes to note empirical idealism explicitly. A
transcendental realist, believing that there are mind-independent
objects that are things in themselves, judges that from the limited
sensory modalities of humans, our representations are wholly inadequate
to establish the reality of noumenal objects (Kant, 1781&1787/2011,
A370). It is a belief in a noumenal world, inaccessible to humans, that
fuels empirical idealism, and adherence to transcendental realism ends
up in a place that Kant does not wish us to be in regarding the natural
sciences. How can we reliably perform the natural sciences if we are
removed from an underlying world of things in themselves?
This concern with the rational basis of the natural sciences is a
recurring theme within the Critique of Pure reason (Kant, 1781&1787/2011,
BXXII-BXIII). In the fourth paralogism, Kant repeatedly states the issue
with Descartes’ form of sceptical idealism. Descartes is a
transcendental realist; Kant sees this as producing a problem that we do
not wish to be in concerning natural science. The sceptical idealist
says that we can only rely on our inner perception. Therefore we are
only inferring outer perceptions; therefore, the outer perceptions can
only ever have a doubtful existence (Kant, 1781&1787/2011, A368). The
uncertainty in the kind of inferences that the sceptical idealist must
make part of her system is intolerable to Kant. Kant wishes to put
forward his system that as discussed in section 2, refutes
idealism and establishes a “possible certainty” in regards to outer
objects and perceptions (Kant, 1781&1787/2011, A367).
For Kant, the solution is to be a transcendental idealist. If one does
not regard there being anything beyond our representations, then Kant
argues that we can be empirical realists. We can put natural science on
a solid footing from empirical realism as Kant desires (Kant, 1781&1787/2011,
BXXII-BXXIII). As a transcendental idealist and empirical realist, Kant
argues that we can “admit the existence of matter” (Kant, 1781&1787/2011,
A370), through his refutation of idealism argument. We are using the
inner experience as proof of the existence of outer experience as seen
in section 2.
In the fourth paralogism, Kant is concerned with knowledge rather than
reality. For Kant, the limits of human knowledge carry more weight than
metaphysics. Kant’s transcendental idealism seems more about having a
valid and justified basis for human knowledge than anything else. I read
Kant to state this later in the fourth paralogism, “from perceptions
knowledge of objects can be generated” (Kant, 1781&1787/2011, A376). In this
quotation, Kant describes our real interaction with the world; we
generate knowledge about outer objects through perceptions, which, as
seen in Kant’s refutation, must exist for our inner sense to exist.
Transcendental idealism allows us to be empirical realists.
Transcendental idealism acknowledges the limits on human knowledge
imposed by our a priori sensibility of space and time and how this
conditions our experience. We can generate meaningful knowledge about
external objects, conditioned by space and time by considering those
perceptions that are connected to empirical laws as real. This is how
science operates, as an empirical realist endeavour, not an empirical
idealist one as transcendental realism would necessitate.
There is further evidence for this reading of transcendental idealism in
the fourth paralogism. Around A373 onwards, in this section of the
Critique Kant wishes to clear up some possible ambiguities in
language. Kant desires to make once again clear what space and time are;
they are a priori representations that are our forms of sensible
intuition (Kant, 1781&1787/2011, A373). They exist
only in us (Kant, 1781&1787/2011, A373), and thus Kant
only wishes to say things about ‘things’ that exist because of us, i.e.,
through perceptions that come from and our conditioned by our sensible
intuitions. He thus distinguishes between objects that one may call
transcendentally external and things found in space (Kant, 1781&1787/2011,
A373), i.e., within our sensible intuitions. Therefore, transcendental
idealism, which may be better understood from the empirical realism
aspect, is only concerned with what exists in our sensible intuitions.
This provides more evidence for Kant’s desire to say more about
knowledge than metaphysics. What we can know about reality is, for all
intents of purposes, reality for us. To attempt to say more is the
antithesis of the whole project of the Critique of Pure Reason
which aims to show which areas of knowledge are inaccessible by their
very nature (Kant, 1781&1787/2011, BXXV).
This reading of Kant’s transcendental idealism as an epistemic or
metaepistemic system rather than a metaphysical one will return in the
next section when we look at the ongoing debate around interpretations
of transcendental idealism.
4 Two-aspect or two-world
In the Western tradition, Kant’s transcendental idealism does seem to
be a genuinely new position, most notably as an anti-realist position
(Braver 2007,
34). As we have seen in the previous sections, most philosophers
of the sceptical idealist type are certainly transcendental realists.
Moreover, those of the dogmatic type deny all external experience, which
certainly implies, at the very least, underlying inaccessibility of
reality outside of the internal sense. Transcendental idealism may seem
an odd position, to not regard things in themselves at all, but only to
regard outer things as to exist when in our sensible intuition. We shall
now examine how Kant regards noumena more generally. Interpretations of
Kant’s transcendental idealism have generally hinged on how Kant is
interpreted to understand noumena and their metaphysical and epistemic
position within the Kantian system.
Kant conceives a noumenon in two manners, a positive and a negative
conception, the former he finds contradictory and therefore of little
interest and the latter conceivable but irrelevant when the reality is
regarded through a lens of empirical realism. The positive conception of
the noumenon, this Kant defines as an “object of non-sensible intuition”
(Kant, 1781&1787/2011, B307). Kant
immediately disregards the positive conception of a noumenon as it would
require a special mode of intuition, which humans patently do not
possess. We cannot conceive more forms of sensible intuition (Kant, 1781&1787/2011,
B307). Kant thus disregards the positive conception of the noumenon as
no human possesses the ‘intellectual’ (Kant, 1781&1787/2011, B307).
The second conception of a noumenon, the negative conception, states
that a noumenon is a thing that is “not an object of our sensible
intuition” (Kant, 1781&1787/2011, B307). Kant views
this as the only possibility for conceiving a noumenon (Kant, 1781&1787/2011,
A252). Kant acknowledges that whilst it is conceivable that there exists
a non-sensible form of intuition, being admissible metaphysically is not
the same as having any bearing on reality. Kant believes himself to have
proven and given a description of our sensible intuition and that
nothing else is possible. Nevertheless, this is all coherent within
transcendental idealism as we are only concerned with the empirical
realism of outer things in our a priori sensibility of chiefly space in
this case.
We shall now look more carefully at the contemporary debate around the
interpretation of the ‘two-aspect’ and ‘two-world’ interpretations
mentioned in the introduction. The ‘two-world’ interpretation is the one
that essentially reads Kant to be making meaningful metaphysical between
phenomena and noumena. Henry Allison aims to show this ‘two-world’
position as being produced from Kant’s subjectivist starting point (Allison 2004, 5).
From this starting point, Kant must maintain that things only seem
spatial or that appearances are spatial (Allison 2004, 5). Both positions
are uncomfortable, the first that appearances only appear spatial seems
to bring us back to sceptical idealism, and the latter position seems to
force us to regard appearances (mental constructs) as extended in space
(Allison 2004,
6). Allison states that the ‘two-world’ interpretation hinges on
Kant wishing to maintain that we only know things as they appear to us,
i.e., phenomena. To make his system compatible with empirical realism,
he shifted to state that we know appearances and that they are spatial
(Allison 2004,
6). Allison argues that the main point of the ‘two-world’ camp is
to do with the meaning of the word ‘knowledge’ (Allison 2004, 6). Knowing about
something in the ‘two-world’ camp means knowing how it is, i.e., as a
noumenon. However, for Kant, we cannot know anything about the noumenal
world, so we see idealism return with force. This idealism can be
characterised as either sceptical or dogmatic. The sceptical formulation
would say that we can not know anything with certainty about the
noumenal. In contrast, the dogmatic formulation would say that noumena
are outside of our a priori sensibility, of space and time, so we are
certain that they are unknowable (Allison 2004, 6–7).
First, we shall see Allison’s refutation of the two-world dogmatic
transcendental idealism and then the sceptical. In the dogmatic case,
proponents such as Paul Guyer argue that no extra noumenal objects are
required. We experience ordinary objects that must be considered only as
things in themselves when our sensibility is removed, i.e., ordinary
objects with space and time removed (Wood et al. 2007, 14).
Thus, things in themselves are anything like our representations of them
as we conform them to our cognition via space and time. Allison argues
that this is an incoherent position as it means we would have to read
Kant as identifying ordinary objects such as tables, chairs and books
with things in themselves. Whilst simultaneously denying that they have
the properties that we experience them to have. I find this incoherence
problematic; the epistemic reading I have developed as I have analysed
the text appears fully coherent at this time. Guyer’s reading seems an
insufficiently sympathetic interpretation that would then discount any
benefit to empiricism and natural science that Kant has developed.
Rae Langton presents the most useful conception of the sceptical
‘two-world’ interpretation. In her interpretation, an object’s noumenal
properties are intrinsic, and we can only perceive relational properties
(Langton 1998,
81). The relational properties are the phenomena, as something
must affect our sensibility to generate representations within our inner
sense. So we cannot know the intrinsic or noumenal properties as we
cannot intuit them. Allison argues that whilst it is correct that we
cannot determine the intrinsic properties an object has. The
metaphysical use of noumena and phenomena is not correct within Kant’s
work on the conditions for the representation of objects, which Allison
terms epistemic conditions (Allison 2004, 11). Allison’s
argument is similar to how I have interpreted Kant’s concepts of
phenomena and noumena. This is the interpretation that things are
outside of our conditions for intuition and experience but that these
objects are not objects for us (Allison 2004, 12). Thus, phenomena
and noumena are not considered distinct objects that would make our
conditions of experience ontological (Allison 2004, 12). Instead, they
have two aspects as they are two different ways of considering things,
as they appear and as they are in themselves, instead of as two
ontologically distinct categories (Allison 2004, 16).
I find myself in greatest agreement with the two-aspect theory in a few
distinct ways. It is the most epistemological interpretation of
transcendental idealism, which is most in line with how I believe Kant
is trying to set up a coherent scientific knowledge system. The
two-aspect theory does not suffer the sceptical problem of inference
that Kant himself outlined in the fourth paralogism (Kant, 1781&1787/2011,
A368), that the two-world interpretation does suffer. Finally, the
incoherence of the dogmatic two-world interpretation as highlighted by
Allison, leads me to view the epistemic approach most favourably.
In the next and final section, now that we are clear on the
interpretation of transcendental idealism, we most favour from this
analysis. We shall see how it applies to interpretations of quantum
physics and which interpretation we can surmise Kant would have been
most likely to endorse.
5 Kant and Quantum
Some two centuries later, Kant’s transcendental idealism may be
applicable and possibly be somewhat vindicated in quantum physics. A
persistent issue for quantum physics is metaphysical interpretation.
Understanding what is implied for reality by the uncertain and
probabilistic clouds that are the wavefunctions of quantum systems is an
ongoing debate. The ‘collapsing’ of these wavefunctions into observable
outcomes is a decades-old conceptual problem (Maudlin 2019, 97–98). The
problem in understanding what a wavefunction means has been coupled and
compounded by the observer’s role in quantum physics. In the double-slit
experiment, an electron beam is passed through two slits. When neither
slit is monitored, the electrons possess wave-like behaviour and form
interference patterns on a screen in front of the double slit. When
either slit is monitored, i.e., the behaviour of the observer is
changed, the behaviour of the electrons changes. Now we see electrons
behave as particles, only able to pass through one slit and not form
interference patterns at all (Maudlin 2019, 15–17). As our
knowledge of the wavefunction in a physical sense is rather minimal, we
can only posit what are the most likely behaviours of the physical
observables when we measure them; there seems to be a hint of empirical
realism and transcendental idealism. Within quantum theory, the observer
has now claimed a central place within physics; this seems as if it
would be appealing to Kant and his system of transcendental idealism. We
can be empirical realists, the result of collapsed wavefunctions are
physical observables, but the knowledge that we can possess about
pre-observed empirical quantities and qualities is purely statistical
before a subject-object interaction.
I will argue that the interpretation of quantum physics most natural to
the Kantian is Quantum Bayesianism, referred to by its popular
abbreviation QBism. This interpretation’s core claim is that quantum
physics’s probabilities (wavefunctions) are always subjective. Thus
quantum states (the physical features of the system) themselves are
subjective too (Timpson 2013, 188–89)). Quantum
states are therefore not objective features of reality and are, in fact,
subjective degrees of belief, which is the generally received way to
interpret any Baysian programme (Timpson 2013, 189). This
formulation of quantum physics dissolves the measurement problem and
allows us to understand how the observer is involved in the
subject-object relationship of the quantum world. QBism is an epistemic
theory; much like transcendental idealism, it only commits us to what we
know or believe our likelihood of knowing a particular outcome is what
is natural and fundamental. The thing in itself, i.e., the wavefunction,
is meaningless for us beyond a statistical likelihood of something we
can know. The thing we can know is the empirical result. This seems, if
not a modern scientific vindication of transcendental idealism; it is an
epistemic theory of scientific knowledge that has placed the subject
conditioning the experience of the object to herself as prime, quite a
similarity.
This epistemic theory of quantum physics seems far more appealing to
Kant than other popular theories, which are of a more metaphysical type.
For example, the famous many-worlds interpretation demands that all
quantum states are equally real and exist in parallel universes with
separated histories (Maudlin 2019, 174–77)
proposes a particular metaphysical understanding of reality. This is a
metaphysical interpretation that I believe Kant would find hard to
reconcile with his conception of natural science. It proposes a
transcendental realist position that, as we have seen in his critique of
Descartes, is always vulnerable to scepticism. Quantum physics
metaphysical realist interpretations, to borrow a phrase, being a
“speculative science” (Kant, 1781&1787/2011, BXIV). The
many-worlds interpretation and other interpretations that are forms of
transcendental realism suffer from being un-provable. They would, in my
opinion, lead Kant to assert that, similar to attempting to gain
knowledge of God, is a mere ‘mock combat’ (Kant, 1781&1787/2011, BXV).
Attempting metaphysical interpretations of quantum physics when the
wavefunction has proven to be all the information that we can gain,
seemingly in perpetuity, suggests there is no ‘more’ to be found from a
metaphysical approach. To Kant, I believe this project would seem a
“groping among mere concepts” (Kant, 1781&1787/2011, BXV), especially when
the QBist epistemic approach is already capable of dissolving problems
that transcendentally realist theories continue to struggle to make
sense of (Timpson
2013, 203–4).
6 Conclusions
To conclude, we have found that Kant, combining his proof against
empirical idealism and his critique of Descartes, has determined a
system, transcendental idealism, for providing a solid basis for natural
science. Being a transcendental idealist is a radical position which
solves the issue of being forced to infer reality and the existence of
outer objects by using the dependence of our inner experience on our
outer experience. This allows empirical realism, which means that what
we experience is true and real as anything else is beyond our knowledge
and does not exist for us.
I have found my reading of Kant’s text on idealism most in line with the
epistemological interpretation outlined by Henry Allison, known as the
two-aspect interpretation. This denies the ontological distinction
between phenomena and noumena and agrees with my reading.
Finally, we looked at the metaphysics of quantum theory and found that
contemporary QBism possesses many features that I believe would make it
attractive to Kant. It is an epistemic theory that dissolves several
problems in ontic quantum interpretations. QBism limits what we know
about quantum states and reality and notes subjectivity and the
observer’s role in a quantum system. QBism performs all this whilst
adhering to empirical realism in the observable outcomes of quantum
physics. All these characteristics are remarkably familiar within Kant’s
system.