Forthcoming in Kantian Review 25/3, September 2020
The Dialectical Illusion in Kant’s Only Possible Argument
for the Existence of God
NOAM HOFFER
Ben-Gurion University of the Negev
Email: noamhoffer@gmail.com
Abstract
The nature of Kant’s criticism of his pre-Critical ‘possibility proof’ for the existence of God,
implicit in the account of the Transcendental Ideal in the Critique of Pure Reason, is still under
dispute. Two issues are at stake: the error in the proof and diagnosis of the reason for committing
it. I offer a new way to connect these issues. In contrast with accounts that locate the motivation
for the error in reason’s interest in an unconditioned causal ground of all contingent existence, I
argue that it lies in reason’s interest in another kind of unconditioned ground, collective unity.
Unlike the conception of the former, that of the latter directly explains the problematic
ontological assumption of the possibility proof, the existence of intelligible objects as the ground
of possibility. I argue that such Platonic entities are assumed because they are amenable to the
kind of unity prescribed by reason. However, since the interest in collective unity has a
legitimate regulative use when applied to the systematic unity of nature, the conception of God
entailed by the possibility proof is retained as a regulative idea of reason.
Keywords: Kant, Only Possible Argument, Ideal of Reason, Dialectical Illusion
Introduction
In the Critique of Pure Reason, Kant famously argues for the impossibility of proving the
existence of God by refuting three arguments, the ontological, the cosmological and the physico1
theological.1 He also criticizes these arguments in the pre-Critical period.2 Yet in texts from this
period Kant also presented his unique theoretical argument for the existence of God, usually
called the possibility proof. This argument is not explicitly discussed in the Critique, but it is
mostly accepted that Kant’s discussion in section two of the chapter ‘The Ideal of Pure Reason’,
titled ‘The Transcendental Ideal’, involves an implicit criticism of the possibility proof.3
Following Grier’s influential account of Kant’s critique of metaphysics (Grier 2001: 9-10), the
reconstruction of Kant’s criticism can address two issues: the metaphysical error in the proof
itself; and the illusion motivating the metaphysical error, which supposedly stems from a certain
interest of reason.
Regarding the metaphysical error, Abaci’s recent elaborate and illuminating account identifies it
as taking the principle that ‘every real possibility must be grounded in actuality’ (the actualist
principle, AP) (Abaci 2017: 262) as an ‘ontological principle unrestrictedly applying to the real
possibility of things in general’ (264).This ontological guise of the principle grounds the
inference to a necessarily existing being. Regarding the motivation, Abaci locates the source of
the error in a way which is mostly continuous with Grier’s account of the illusion related to the
transcendental ideal (272-4, 279, 281). According to this account, the motivation for taking the
conclusion as objective is not presented in the reconstruction of the possibility proof implied in
section two, but only in section three of the Ideal chapter, which details a separate illusory
inference leading to the necessary ground of all contingently existing things (Grier 2001: 252-6,
2010: 272-5).
The account I develop in this article is mostly in agreement with Abaci’s account of the
metaphysical error. But I disagree with Abaci and Grier about the nature of the transcendental
illusion that motivates it. Building on Abaci’s account, I make the ontological assumption of the
2
possibility proof more specific. When applied as an ontological principle to things in general, AP
entails that possibility is grounded in intelligible (abstract) entities from which the proof aims to
infer an ultimate ground – God. I argue that this Platonist assumption makes the proof appealing
because such an intelligible ground is amenable to the collective unity sought by reason, a
conceptual and systematic kind of unity. For the critical Kant, the existence of a unified
intelligible ground of the possibility of things transcends the conditions of possible experience
and hence is unknowable. Yet the assumption of such a ground is retained as a regulative idea for
science because it expresses the interest of reason in the systematic unity of the laws of nature.
In section 1 I briefly present the pre-Critical possibility proof and its transformation into the
transcendental ideal of the first Critique. In section 2 I begin to unpack Kant’s implicit criticism
of the error in the possibility proof, the assumption of an ontological ground for the possibility of
things in general. In section 3 I show that the implicit criticism also encompasses the motivation
of the error, reason’s interest in collective unity as the unconditioned ground of all possibility. In
section 4 I address the interpretation espoused by Grier, according to which the illusion
motivating the error lies in a separate inference to an unconditioned ground for the existence of
contingent things. I argue that this can motivate assent to the conclusion, but not the initial
assumption of the proof, the ontological AP. I also show that this reading is problematic when
considering Kant’s pre-Critical refutation of the cosmological argument. To support my
alternative explanation, in section 5 I expand on the erroneous ontological commitment of the
possibility proof, the assumption of intelligible objects (intelligibilia) as the ground of
possibilities. I support this explanation by recourse to the Amphiboly chapter, which clarifies
why the transcendental ideal is the paradigmatic example of an intelligible object. In section 6 I
provide further evidence for my reading by showing how the positive regulative role of the idea
3
of God stems from the same interest in collective unity which motivates the error of assuming
the existence of intelligible objects.
1. The Transcendental Ideal and the Possibility Proof
Kant’s pre-Critical possibility proof for the existence of God is first presented in 1755 (NE 1:
395) and then elaborated in 1763 (OPA 2: 77-92). The gist of the argument is as follows:
(1) The possibility of any individual thing presupposes not only a logical condition, i.e. the
non-contradiction of its predicates, but also a material condition: the content of its
predicates is given through some actual thing, either directly from predicates of an actual
thing or indirectly derived from fundamental predicates of an actual thing (OPA 2: 77-8).
(2) Using the notion of a material condition, Kant contends that the possibility of any
individual thing is grounded in something actual (following Abaci, principle AP).
(3) If there are no actual things, i.e. nothing exists, no predicates can be given, and therefore
nothing is possible.
(4) It is impossible that nothing is possible and therefore
(5) It is necessary that something exists.
(6) There exists one being grounding all possibilities. Since without this being nothing would
be possible, this being exists necessarily.4
(7) This necessarily existing ground of all possibility is God.
The argument is problematic in various ways as pointed out by many commentators.5 However, I
will forgo here the examination of the various problems because my concern is Kant’s own
4
rejection of the proof in the Critique of Pure Reason and the dialectical illusion he associates
with it.
I will only make one point about (2) which is relevant for the rest of my argument. There are
various interpretations about the nature of the grounding relation between the actual thing and
the possible predicates. The debate revolves mainly around the question whether possible
predicates are grounded in virtue of being instantiated in something actual or by some other
means.6 Abaci, for example, maintains that a predicate is made possible in virtue of its
‘instantiation’ in an existing thing (2017: 265). It is true that a predicate’s being instantiated
logically entails that it is possible. Under some accounts, instantiation might also be a condition
for the epistemic fact that a predicate is knowable. Indeed, Kant sometimes expresses the
grounding relation in epistemic terms, as the requirement for a material element to be given for
thought.7 But since the argument aims to derive an ontological claim from the grounding of
possibility, the grounding relation is not only a logical or epistemological relation but rather a
metaphysical one that entails some ontological assumptions about its relata.8 Thus, apart from
the question of ‘instantiation’, we need to consider other features of the relata to reveal what is
entailed ontologically from the grounding of possibility. The grounded things are predicates of
possible things and so are abstract entities, and therefore it is plausible to think also of the ground
as an abstract entity. One way to characterize such a metaphysical grounding relation is as a sort
of Platonism about the grounds of possibility9. I will argue that Kant’s realization that proving
the existence of God from the grounds of possibility involves the reifications of concepts into
abstract entities explains the ultimate rejection of the possibility proof, as well as the regulative
significance of the corresponding conception of God.
5
Kant continued to value this proof in the Critical period.10 In his lectures on rational theology
given after the publication of the Critique, he continues to mention it favourably:
Here [in OPA] it was shown that of all possible proofs, the one which affords us the most
satisfaction is the argument that if we remove an original being, we at the same time
remove the substratum of the possibility of all things. But even this proof is not
apodictically certain; for it cannot establish the objective necessity of an original being,
but establishes only the subjective necessity of assuming such a being. (LPR 28: 1034)
Although the proof ‘affords the most satisfaction’, Kant states that it cannot prove the objective
existence of God, but only the subjective necessity of assuming it. But what prevents the proof
from being apodictically certain? Kant’s transcendental idealism entails that knowledge is
limited to what can be given in sensible intuition and the a priori conditions of experience.
Hence knowledge about a supersensible object such as God is impossible. The natural question
that arises is whether, beyond the restrictions of transcendental idealism on knowledge of the
conclusion, there is a fallacy within the proof itself. Without locating such a fallacy, the proof
could perhaps provide a counter-argument overriding the justifications for transcendental
idealism, proving that we can know the existence of at least one object of traditional metaphysics
independently from the conditions of possible experience.11
In the Critique itself, Kant does not explicitly mention the possibility proof among the arguments
for the existence of God. But a similar line of thought underlies his discussion of the theoretical
conception of God as the ens realissimum (the most real being) in section two of ‘The Ideal of
Pure Reason’, ‘the transcendental ideal’ (A571-84/B579-662). The construal of this conception
6
begins here not from the grounding of possibility, but from the principle of thoroughgoing
determination:
Every thing, however, as to its possibility, further stands under the principle of
thoroughgoing determination; according to which, among all possible predicates of
things, insofar as they are compared with their opposites, one must apply to it (A5712/B599-600)
To put it simply, this principle prescribes what it is like to know everything there is to know
about something, so that this knowledge would suffice ‘to cognize a thing completely’, i.e. as an
individual object, solely through its concept (A573/B601). The principle of contradiction places
logical constraints on concepts so that at most only one of a pair of contradicting predicates can
apply to each concept of a thing. The principle of thoroughgoing determination, on the other
hand, specifies the conditions for the individuation of a thing through its concept, i.e. in terms of
a set of predicates: that one of each pair of all possible contradicting predicates applies to the
object. According to the principle of the identity of indiscernibles, objects with the same set of
predicates are identical, and hence the complete set of predicates uniquely identifies an
individual object. Thus determining the complete set of predicates presupposes a totality of all
possible predicates, ‘the entire storehouse of material from which all possible predicates of
things can be taken’(A575/B603). The sum total of all predicates is also the whole of reality
(omnitudo realitatis) when considering positive predicates as signifying a reality and negative
predicates as lack of reality. Each concept of an individual thing can then be determined by
selecting a subset from this whole. Till now, the result is entirely conceptual, without making an
ontological claim:
7
Yet all of this does not signify the objective relation of an actual object to other things,
but only that of an idea to concepts, and as to the existence of a being of such preeminent
excellence it leaves us in complete ignorance (A579/B607)
What enables the ontological shift in the final step, is regarding the ground of the whole of
reality as a single object. The ground of all reality should be thought of as prior to its parts and
not as a mere aggregate of parts. Hence there is a shift from the notion of a sum total that can be
limited to something that grounds all realities:
the highest reality would ground the possibility of all things as a ground and not as a
sum total; and the manifoldness of the former rests not on the limitation of the original
being itself, but on its complete consequences, to which our whole sensibility, including
all reality in appearance, would then belong, which cannot belong to the idea of a highest
being as an ingredient. (ibid.)
One reason for this shift is reason’s demand for an unconditioned condition. An aggregate of
independent parts would be conditioned by their parts and therefore not unconditioned. A second
reason appears at the end of the last quote: the ground of all reality is also the ground of sensible
realities, and those can only be grounded in the highest being but not included in it without
sliding into Spinozism. What is important to note is that this shift brings us closer to the
ontological commitment of OPA: the transcendental ideal is not only a concept of an aggregate
of predicates but an ontological ground for predicates, which means that they are being regarded
ontologically as abstract entities.
When taken as a single object, the ground of all reality is the most real being, the ens
realissimum (A576/B604), or in other words, God (A580/B608). Since the conceptual
8
individuation of things explains their possibility qua individuals, God as the condition for
thoroughgoing determination is also ‘the material ground of all possibility’ (A573/B601; cf.
A576/B604). The latter is the same term used in the possibility proof. The same ‘all of reality’
required for thoroughgoing determination of things is also the material ground, the real element
of their possibility in the pre-Critical sense. Thus the affinity between this argument and the
construal of the ideal of reason in the Critique is evident, textually and conceptually.12
2. The Error of Subreption in the Possibility Proof
Since the construal of the ens realissimum is similar to the reasoning of the possibility proof, it is
plausible to look for criticism of the proof in the analysis following this construal. Kant makes it
clear that forming the concept of the ens realissimum does not include an assertion about the
existence of its object:
It is self-evident that with this aim – namely, solely that of representing the necessary
thoroughgoing determination of things – reason does not presuppose the existence of a
being conforming to the ideal. (A577-8/B605-6)
The conclusion of the possibility proof, however, does assert the actual existence of God, and
from similar considerations to the ones leading to the construal of the ens realissimum. Where
does this erroneous conclusion come from? After presenting how reason construes the ens
realissimum, Kant sets the task to identify the source of the error of inferring its existence, the
dialectical illusion:
It is not enough to describe the procedure of our reason and its dialectic; one must also
seek to discover its sources, so as to be able to explain this illusion itself … Therefore I
ask: How does reason come to regard all the possibility of things as derived from a single
9
possibility, namely that of the highest reality, and even to presuppose this possibility as
contained in a particular original being? (A581/B609)13
Kant’s account of the nature of the error that leads reason to regard ‘all the possibility of things’
as grounded in one being is packed into the last two paragraphs of section two and is very
succinct and opaque. I will, therefore, analyse it in detail. The account begins with the starting
premise of the possibility proof, the grounding of possibility in actuality (AP). Kant states that
this principle is valid for the possibility of cognizing objects of experience:
The possibility of objects of sense is a relation of these objects to our thought, in which
something (namely, the empirical form) can be thought a priori, but what constitutes the
material, the reality in appearance (corresponding to sensation) has to be given; without
that nothing at all could be thought and hence no possibility could be represented. (ibid.)
Kant begins by alluding to the Postulates of Empirical Thinking (A218-26/B266-74).14 In their
legitimate empirical use, the categories of modality do not determine anything in the object itself
but only the relation of thought to the object. Two elements can be discerned in this relation.
First, the object has to correspond with the formal conditions of experience, the a priori forms of
sensible intuition and the categories. Secondly, the content (or matter) of the sensible realities
which belong to the object ‘has to be given’ (A581/B609), i.e. regarded as actual.15 Thus the
possibility of cognizing empirical objects presupposes the whole of experience as an actual sumtotal of all sensible realities:
But because that which constitutes the thing itself (in appearance), namely the real, has to
be given, without which it could not be thought at all, but that in which the real in all
appearances is given is the one all-encompassing experience, the material for the
10
possibility of all objects of sense has to be presupposed as given in one sum total
(A582/B610)
This sum total is then conceived as the condition of the thoroughgoing determination of
empirical objects: ‘all possibility of empirical objects, their difference from one another and their
thoroughgoing determination, can rest only on the limitation of this sum total’ (ibid.) This line of
thought is analogous to the starting point of the possibility proof. Also there, Kant distinguishes
between the formal aspect of possibility (the principle of non-contradiction), and the material
aspect, the actual ground of possibility (AP). But Kant contends that this analogy is deceptive:
while AP is true for cognizing the possibility of empirical objects, it is not applicable to
grounding the possibility of things in general:
In accordance with a natural illusion, we regard as a principle that must hold of all things
in general that which properly holds only of those which are given as objects of our
senses. Consequently, through the omission of this limitation we will take the empirical
principle of our concepts of the possibility of things as appearances to be a transcendental
principle of the possibility of things in general (ibid)
This is a case of ‘transcendental subreption’, by which a principle of possible experience is
illegitimately used to gain knowledge of things independently of possible experience. i.e. thingsin-themselves.16
As Abaci shows, in its legitimate use for objects of experience, AP is an epistemological
principle: for cognizing the possibility of empirical objects as fully determined regarding all
realities, we presuppose the actuality of all the empirical realities in one sum total.17 The
metaphysical error lies in substituting an epistemological AP applicable to the cognition of
11
objects of experience with an ontological AP applied to things in general (Abaci 2017: 285). But
a complete critique of the possibility proof requires not only identifying the metaphysical error
but also explaining the transcendental illusion that motivates reason to commit the error. Abaci
focuses mainly on the error, and in continuity with Grier claims that the explanation of the
illusion comes only in section three of the Ideal chapter. In the next section I lay out my
alternative account of the illusion, and in section 4 I argue against Grier’s account.
3. Collective Unity and the Formation of the Transcendental Ideal
In what follows I will show that there is an implicit account of a motivating Illusion already in
section two, in the notion of collective unity which comes up in the last paragraph of the section:
That we subsequently hypostatize this idea of the sum total of all reality, however, comes
about because we dialectically transform the distributive unity of the use of the
understanding in experience, into the collective unity of a whole of experience; and from
this whole of appearance we think up an individual thing containing in itself all empirical
reality. (A582/B610; italics mine)
The subreption that transforms the epistemological AP into an ontological AP is manifested by
hypostatization, i.e. regarding the idea of a ground of possibility as a real object. I take the
‘because’ in the above sentence to indicate a purposive explanation: the subreption is motivated
by an interest in transforming distributive unity into collective unity. What is the difference
between these kinds of unity? In the Appendix to the Dialectic, Kant describes them as follows:
just as the understanding unites the manifold into an object through concepts, so reason
on its side unites the manifold of concepts through ideas by positing a certain collective
12
unity as the goal of the understanding's actions, which are otherwise concerned only with
distributive unity. (A644/B672)
The unity imposed by the understanding on the sensible manifold is distributive, while collective
unity is a unity of reason, imposed on concepts (cf. Guyer 2003: 5). According to their seat
correspondingly in the understanding or in reason, we can make the following distinction. The
distributive unity of the understanding is generated by the relations among objects of experience,
the way in which each object is constituted by its relations to all other objects and the cognizing
subject.18 This unity is therefore distributed equally among its parts. The indeterminate whole
composed thereby is only thought as an open series enabling the search for further relations
without a definite endpoint. However, as a faculty of inferences, reason demands a different kind
of unity, a collective unity of a system derivable from a single ultimate principle:
[W]hat reason quite uniquely prescribes and seeks to bring about concerning it [the
concepts of the understanding] is the systematic in cognition, i.e., its interconnection
based on one principle. (A645/B673)
Although the paragraph at the end of section two refers to the ‘collective unity of a whole of
experience’ leading to an ‘individual thing containing in itself all empirical reality’, we should
note that this collective unity is not a necessary condition for the possibility of experience but a
mere idea of reason. Since collective unity originates in the faculty of reason, it requires
something beyond what is available through the synthesising function of the understanding
regarding sensible intuition.19
This ‘collective unity of a whole of experience’ is then ‘by means of the transcendental
subreption … confused with the concept of a thing that stands at the summit of the possibility of
13
all things, providing the real conditions for their thoroughgoing determination’ (A583/B611).
What motivates this confusion? My claim is that the confusion, the error of subreption, is
motivated by the interest of reason in collective unity. As noted above, the unity of experience is
merely distributive, the unity resulting from the spatial, temporal and categorical relations
between the objects of experience. But the interest of reason is to regard any manifold as a
collective unity, i.e. a unity in virtue of being derived from a single principle. Since the unity
between the actual objects of experience cannot be collective but only distributive, reason
presupposes unity in what grounds the possibility of the objects of experience. The ontological
ground of possibility is amenable to the unity of reason because it is an abstract entity that can be
thought through the reification of concepts.20
Thus an important step in the course of reason concluding in the existence of the ens realissimum
is the reification of a concept that unites all other concepts systematically as an actual object that
grounds all possibility of things. This is suggested in a footnote: ‘This ideal of the supremely real
being, even though it is a mere representation, is first realized [realisiert], i.e., made into an
object [Objekt], then hypostatized’ (A582-3/B610-1, fn.).
The hypostatization (assigning existence) of the ens realissimum is the erroneous conclusion, but
there is a prior step mentioned in this sentence, that of ‘realization’, i.e. thinking it as an object,21
or what I called above reification. Once it is conceded that the Ideal designates an object that
grounds all possibility, it is natural to infer its necessary existence, as without it nothing would
be possible.
Let us summarize Kant’s account of the errors that follow from the construal of the ens
realissimum:
14
1. A principle valid for the possibility of cognizing empirical objects is applied to the possibility
of things in general for which it cannot be demonstrated to be valid (the dialectical
subreption of AP).
2. The unity of experience which is only distributive is transformed into a collective unity of a
system of concepts, in accord with an interest of reason.
3. Using this ontological AP, reason infers a single actual object which is the unconditioned
ground of the possibility and collective unity of all things in general – God.
What is the relation between (1) the dialectical subreption of AP and (2) the error of substituting
collective unity for distributive unity? My claim is that there is a rational interest to regard the
unifying distributive relations between empirical objects as grounded by the collective unity of
relations between concepts. Thus reason is tempted to take its interest in (2) as objective,
justifying the ontological commitment entailed by the subreption (1). Regarding the collective
unity of reason as objective means making concepts into objects: making something which
signifies only the relation ‘of an idea to concepts’ into an ‘objective relation of an actual object
to other things’ (A579/B607). This leads to a metaphysical error when the objects thereby
produced, purely intelligible objects, are regarded as existing. In section 5 I will expand on the
nature of these objects and show how they function in the construal of the ens realissimum and
the possibility proof.
The following note provides additional evidence that it is this interest in collective unity which
ultimately motivates the formation of the ens realissimum:
The idea of the unconditioned unity of all objects of thought in an ens entium is necessary
in order to seek for the affinity among everything possible and thereby also
15
thoroughgoing connection as unity of principle. (R5553, 18: 226; the three emphases
mine. Cf. the footnote to A572/B600)
The ens realissimum is construed for the sake of an unconditioned ground of the unity among all
possibilities, i.e. unity among the essences which provide the ‘matter’ for all possible things.
Hence the metaphysical error arises from thinking that the unity of concepts prescribed by reason
has to be grounded in actual intelligible objects: ‘where the universality of thinking through
reason is taken for a thought of a totality of the possibilities of things’ (R5553, 18: 224). In
section 6, I show how this kind of unity receives a regulative status.
4. Transcendental Illusion and Section Three of the Ideal
According to Grier, the construal of the ens realissimum in section two of the Ideal chapter does
not include an explanation of the illusion motivating the error which comes only in section three.
Thus she claims ‘that section 2 and 3 constitute two stages in a single extended argument’.22 The
following passage at the beginning of section three supports this reading:
In spite of its urgent need to presuppose something that the understanding could take as
the complete ground for the thoroughgoing determination of its concepts, reason notices
the ideal and merely fictive character of such a presupposition much too easily to allow
itself to be persuaded by this alone straightway to assume a mere creature of its own
thinking to be an actual being were it not urged from another source to seek somewhere
for a resting place in the regress from the conditioned, which is given, to the
unconditioned (A583-4/B611-2)
Kant claims that the need to assume the material ground for thoroughgoing determination
presented in section two is not persuasive enough for forming the belief in the actual existence of
16
God without another motivation. This other motivation for belief in the existence of God is the
argument that begins with contingent existence known through experience and concludes that
there is something that exists necessarily, a cause for the whole series of contingent things:
If something, no matter what, exists, then it must also be conceded that something exists
necessarily. For the contingent exists only under the condition of something else as its
cause, and from this the same inference holds further all the way to a cause not existing
contingently and therefore necessarily without condition. That is the argument on which
reason grounds its progress to the original being. (A584/B612)
The existence of each contingent thing is caused by something else. The general interest of
reason is to complete the regress of causal conditions, and therefore it postulates an
unconditioned cause for the whole series. This type of inference corresponds to the generic form
of a transcendental illusion that Grier identifies in all the arguments of the dialectic: a transition
from the legitimate yet subjective principle of reason, ‘Find for the conditioned knowledge given
through the understanding the unconditioned’ (P1), to the illusory principle, ‘If the conditioned is
given, the whole series of conditions, subordinated to one another – a series which is therefore
itself unconditioned – is likewise given’ (P2).23 P2 is here applied to the causal series of
contingent things, resulting in a necessary first cause. Kant then continues to assert that only the
unjustified combination of the two lines of thought, the first from the principle of thoroughgoing
determination to the ens realissimum, and the second from the series of contingent things to their
non-contingent cause, leads to the illusion of rational theology in its full force. Reason is
compelled to assume the unconditioned cause for contingent things but has no insight into its
nature. The concept of the most real being is then introduced as ‘best suited to the concept of an
unconditionally necessary being’ (A587/B615). The ens realissimum is best suited for a concept
17
of an unconditioned cause because it is unconditioned also in another sense, as the most real
being which grounds the possibility of everything else.
According to Grier, it is only the need for an unconditioned causal ground of existence added in
section three that accounts for the dialectical illusion motivating the hypostatization of the ens
realissimum.24 Yet her account does not explain the relations between the series of errors
detailed in section two, but only the appeal of using its final conclusion for a different purpose. 25
Therefore, when considering the account of these errors as an implicit criticism of the possibility
proof, locating the motivating illusion only in section three cannot explain how the pre-Critical
Kant thought the possibility proof was convincing in the first place.
Moreover, the argument presented in section three for a necessarily existing cause of all
contingent things is a version of a cosmological argument for the existence of God. Given that
the construal of the ens realissimum in section two correlates with the pre-Critical possibility
proof, locating the illusion only in section three would amount to the claim that the force of the
possibility proof depends on an implicit appeal to the cosmological argument for supplying the
concept of necessary existence. But could Kant be committed to this position? In OPA he
explicitly maintained the opposite view: the possibility proof is the ‘only possible argument’ and
superior to all other arguments, including the cosmological argument from contingency.
The specific criticism of the cosmological argument in OPA (2: 158) is similar to the one
levelled in the Critique (A604-7/B632-5), and shows that it implicitly depends on the Cartesian
ontological argument. What is relevant for the present purpose is Kant’s claim that the possibility
proof is superior to the cosmological proof precisely with respect to the notion of necessary
existence. The possibility proof renders the necessary existence of God intelligible because it
18
proceeds from an analysis of the concept of absolute necessity as that whose non-existence
cancels all possibility, while the cosmological proof appeals to the merely negative notion of the
non-contingent:
It [the possibility proof] is, indeed, an argument derived from the internal characteristic
mark of absolute necessity. Thus, our knowledge of the existence of this being is derived
from what really constitutes the absolute necessity of that same being…
None of the proofs which argue from the effects of this being to its existence as cause can
ever – even granting that they are of the strictest character, which in fact they are not –
render the nature of this necessity comprehensible … from the fact that something is a
first cause, that is to say, an independent cause, it only follows that, if the effects exist
then the cause must also exist, not that the cause exists absolutely necessarily (OPA 2:
91, emphases mine)
I believe that it is unlikely that Kant changed his mind about the independence of the possibility
proof from the cosmological proof. If this is the case, then there should be another kind of
motivating illusion than the one Grier locates in section three, which explains why the mere
conception of the transcendental ideal is mistaken for a proof from the ground of possibility. As I
have shown in the previous section, this illusion stems from the interest in the collective unity of
all possibilities. We should note that the collective unity of the grounds of possibility is also a
form of an unconditioned ground, and hence stemming from the general illusory principle P2,
but it is not the unconditioned ground of existence described in section three.
But how are we to understand Kant’s statement about the lack of convincing power of the
procedure in section two which correlates with the possibility proof? I suggest we take it as a
19
historical-anthropological observation rather than logical. The cosmological argument is more
common in human history because it begins with ordinary experience and does not assume
sophisticated metaphysical reflections:
This is the natural course taken by every human reason, even the most common ... It
begins not with concepts, but with common experience, and thus grounds itself on
something existing. (A584/B612)
[The argument is] so simple and natural that it is suited to the commonest human
understanding as soon as the latter is once led to it. (A589/B617)
Once human reason is led from the causal series of changes to the idea of a first cause, then
further philosophical reflection can supply the idea of a most perfect being as a suitable
candidate for that cause. But the logical course of reasoning as exemplified in OPA and still
supported in the lectures as subjectively valid does not depend on the cosmological argument and
is also not motivated by it, but by another demand of reason, that of collective unity. The next
sections will elaborate on the ontological commitment to intelligibilia motivated by this interest
and its relation to the regulative principle of systematic unity.
5. Intelligibilia and the Ontological Commitment of the Ideal
The error of subreption is that of taking the ‘empirical principle of our concepts of the possibility
of things as appearances to be a transcendental principle of the possibility of things in general’
(A582/B660). What is meant by things in general? In several other places, the term ‘things in
general’ is followed by ‘and in themselves’ (B298/A238, B410). Things in general are thought
not in relation to the conditions of experience but only as they are in themselves. Leaving out all
sensible conditions, any thinkable determination of them would thus be purely intellectual, and
20
the objects would be intelligible objects. We may call these intelligible things in themselves
intelligibilia.26
We can find the assumption of intelligibilia as related to the idea of God in the introduction to
the Dialectic:
in the third kind of sophistical inference, from the totality of conditions for thinking
objects in general … I infer the absolute synthetic unity of all conditions for the
possibility of things in general; i.e., from things with which I am not acquainted as to
their merely transcendental concept, I infer a being of all beings, with which I am even
less acquainted through its transcendental concept, and of whose unconditioned necessity
I can make for myself no concept at all. This dialectical syllogism I will call the ideal of
pure reason. (A340/B398, emphases mine)
The ens realissimum is not construed through direct reference to objects of experience, in
contrast with the cosmological idea which is construed from the totality of appearances. Rather,
it is inferred from the ‘conditions for the possibility of things in general’, hence things-inthemselves with which we are not acquainted. Although nothing can be known about such
things, reason assumes their existence as purely intelligible when inferring the existence of God.
To get a clearer view of the characteristics of these objects, we should note that the ens
realissimum is not only the ground of thoroughgoing determination and the possibility of
everything else, it is also described as the prototype, the perfect example, of things in general:
‘the ideal is thus the original image (prototypon) of all things, which all together, as defective
copies (ectypa), take from it the matter for their possibility (A578/B606)
21
The Platonic overtones in the above passage are not accidental. At the outset of the Dialectic
Kant explicitly borrows the term ‘idea’ (Idee) from Plato to designate concepts of objects that
cannot be given in experience but serve as standards of perfection (A320/B377). Most of Kant’s
examples for the significance of Platonic ideas come from the practical realm. But the Ideal
chapter shows how theoretical considerations also lead reason to form an ontology of degrees of
reality so that the ens realissimum grounds the possibility of all its less perfect copies. By
conceiving the possibility of things in general as intelligibilia, reason reifies concepts as objects
and makes them dependent on the most perfect object which corresponds with the most complete
concept. This is, in other words, Platonism.
This Platonic picture entails that by discerning the features of the prototype, i.e. the ens
realissimum, we can learn what is assumed about the copies, i.e. the objects which depend on it.
Because the ground of thoroughgoing determination is also the ground of possibility, this also
clarifies the ontological commitments of the possibility proof.
The ens realissimum is a paradigmatic example of a thing-in-itself because by having all
perfections and no negations it is individuated solely by conceptual means:
Through this possession of all reality, however, there is also represented the concept of a
thing in itself which is thoroughly determined … an individual being, because of all
possible opposed predicates, one, namely that which belongs absolutely to being, is
encountered in its determination (A576/B604, italics mine).
The Amphiboly chapter provides further details about the characteristics of things-in-themselves
as intelligibilia. The target of criticism in this chapter is the Leibnizian theory of monads, and the
basic thought is that this theory could be justified according to the concepts of reflection if we
22
had cognition of intelligibilia. Yet we do not possess such cognition and the principles valid for
intelligibilia are not valid for objects of sensible intuition. What is important for the present
purpose is that we can also learn from this discussion what intelligibilia would be like had they
existed, and why they are presupposed in the construal of the ens realissimum.
The first pair of concepts of reflection states the identity of indiscernibles (A263-4/B319-20). As
noted in section 1, the principle of thoroughgoing determination as a principle of individuation
depends on this principle, and the ens realissimum itself as a concept of an individual
exemplifies it. Thus the principle of thoroughgoing determination from which the construal of
the ens realissimum begins is fully applicable only to intelligibilia. Also according to the second
and the third pair of concepts of reflection, the ens realissimum is a paradigmatic example of an
intelligible thing in itself: there is no opposition between its realities, and all its determination are
intrinsic rather than relational (A264-6/B320-2).
The Amphiboly chapter does not discuss concepts of modality, but the last pair of concepts of
reflection, matter and form, is directly related to the grounding of possibility:
In every judgment one can call the given concepts logical matter (for judgment), their
relation (by means of the copula) the form of the judgment. In every being its
components (essentialia) are the matter; the way in which they are connected in a thing,
the essential form. Also, in respect to things in general, unbounded reality is regarded as
the matter of all possibility, but its limitation (negation) as that form through which one
thing is distinguished from another. … The understanding, namely, demands first that
something be given (at least in the concept) in order to be able to determine it in a certain
23
way. Hence in the concept of pure understanding matter precedes form. (A266-7/B322-3,
emphases mine)
Appearances are first individuated by the spatiotemporal form, and only then determined with
regard to their content: ‘the form of intuition (as a subjective constitution of sensibility) precedes
all matter (the sensations), thus space and time precede all appearances and all data of
appearances, and instead first make the latter possible’ (A267/B323). But regarding intelligibilia,
if there were such things, the existence of the matter of their reality could be inferred from their
real possibility. The affinity of this discussion of matter and form in the Amphiboly to the
construal of the ens realissimum and the possibility proof is clear. The reasoning to the matter of
all possibility is conditionally valid for intelligibilia: if one could cognize the existence of such
objects, then one could also cognize a sum total of all intelligible reality grounding their
possibility.
We should also notice in the above passage that components of intelligible objects are modelled
after concepts (the predicates being related in judgement) and are called essentialia, the material
to be combined in the essential form of a thing. When considering intelligibilia, the matter of all
possibility is the totality of essences. Thus the conclusion of the possibility proof that the matter
of all possibility is grounded in God is equivalent to the grounding of all essences in God. This
notion of a unified ground of essences is exactly what Kant found valuable in the conception of
God entailed by the possibility proof and allows its transformation into a regulative idea, as I will
suggest in the next section.
24
To conclude: since the ens realissimum as the paradigmatic concept of an intelligible thing-initself is inferred from being the archetype (‘the original image’) grounding the possibility of all
other things, those things, i.e. intelligibilia, are assumed to exist.
6. The Regulative Use of the Ideal
In the series of the metaphysical errors following the formation of the ens realissimum, it is not
only realized and hypostasized as an existing object but also made into a thinking substance:
This ideal of the supremely real being, even though it is a mere representation, is first
realized, i.e., made into an object, then hypostatized, and finally, as we will presently
allege, through a natural progress of reason in the completion of unity, it is even
personified; for the regulative unity of experience rests not on appearances themselves
(of sensibility alone), but on the connection of its manifold by understanding (in one
apperception); hence the unity of the highest reality and the thoroughgoing
determinability (possibility) of all things seems to lie in a highest understanding, hence in
an intelligence. (A583/B611, fn.; italics mine)
As argued above, this whole series of errors is motivated by an interest in collective unity. Since
this is a conceptual rather than sensible unity, it is plausible to regard its ground as intelligent.
But what is important for the present purpose is that this unity is described as regulative, hinting
at the positive regulative role of the ens realissimum.
The regulative use of the ideas of reason is the subject of the Appendix to the Dialectic. The idea
of God is specifically related to the systematic unity of nature: ‘the idea of that being [God],
means nothing more than that reason bids us consider every connection in the world according to
principles of a systematic unity’ (A686/B714).
25
In contrast with the legitimate regulative use, the possibility proof not only ‘bids us consider’,
but concludes that there exists an object grounding the systematic unity of all possible things.
But leaving aside the objective status of the conclusion, it is important to note that in the preCritical possibility proof the conception of God is also related to the systematic unity of nature.
The second part of OPA (2: 93-155) discusses at length the systematic order of nature. Kant
there criticizes explanations of natural facts that appeal to contingent divine intervention instead
of necessary laws of nature. But investigating the latter is not in contrast with including God in
the metaphysical explanation of nature. The ground of all possibility is the ground of essences,
i.e. the necessary properties of things and the lawful relations between them (cf. Insole 2011).
Hence investigating the unity of the laws of nature stemming from the essences of things coheres
with the conception of God as the single ground of all possibility established in the first part of
OPA:
Our purpose from now on will be to see whether the internal possibility of things is itself
necessarily related to order and harmony … so that, on this basis, we could establish
whether the essences of things themselves indicate an ultimate common ground. (2: 92)
Kant espoused this view about God as the ground of essences and the laws of nature at least from
the 1750s in his drafts on optimism (R3704, 17: 234) and the Universal Natural History (1: 2223, 332), and he continued to hold it in LPR (28: 1035).
The usefulness of this conception of God is transformed in the Critique into a regulative idea
expressing the need to assume the unity of the laws of nature. But taking this need as objective
rather than subjective leads to the dogmatic assumption of the possibility proof, that essences
26
exist as intelligible things in themselves from which it is possible to infer their ultimate ground,
God.
In LPR Kant contends that the possibility proof establishes ‘the subjective necessity of assuming
such a being’ for explaining ‘what in general the possibility of something consists in’ (LPR 28:
1034). A note from the 1770s provides further elaboration of this subjective necessity:
Even if the existence of God does not follow from the conditions on which we ground the
concept of possibility, it nevertheless follows sufficiently from the concession that we can
judge a priori about this. The subjective conditions of thinking therefore serve very well
for convincing cat anthropon, but not apodictically. (R5508, 18:203; emphasis added)
The possibility proof is invalid without the assumption of a priori knowledge about the
conditions of possibility in general. Since it proceeds from the ontological ground of possibility
in general and not from the epistemic condition for cognizing the possibility of empirical objects,
such a priori knowledge would amount to cognition of the matter of possibility as intelligible,
hence knowledge about the existence of intelligibilia.27 Assuming this kind of knowledge is, in
fact, assuming that the structure of thought is also the structure of reality,28 and therefore the
argument is subjectively valid for human thought, cat anthropon (ad hominem). While this
subjective validity is the illusion motivating the unjustified assumptions of the possibility proof,
it also correlates with its positive regulative use. Thus although there can be no cognition of
essences qua intelligibilia, the idea of God construed as their ground expresses the rational
interest in discovering the unity of the laws of nature.
Conclusion
27
I have shown that the conception of God as the ens realissimum and the ground of all
possibilities is construed from the assumption of intelligible objects. For the pre-Critical Kant,
the starting assumption that there are entities such as essences that ground the possibility of
empirical objects was unproblematic. From these intelligible entities it was also unproblematic to
construct a conception of God. For the Critical Kant, cognition of essences as things-inthemselves is impossible for human cognition. Therefore assuming that these intelligible
building blocks of the possibility proof exist objectively is the erroneous result of a dialectical
subreption, the application of a principle whose validity cannot be demonstrated for things in
general. I have argued that this metaphysical error is not motivated by the interest of reason to
seek the unconditioned ground of contingent existence, but by an interest in a different kind of
unconditioned, that of conceptual collective unity. It is this interest that also explains the
regulative role of the idea of God. Even though the intelligible grounds of possibility are not
objects of knowledge, their amenability, as purely intelligible, to collective unity correlates with
what guides scientific inquiry, the systematicity of empirical concepts. For this reason, even
when losing its objective validity, the conception of God retains a subjective validity as the Ideal
of reason, ‘a concept which brings to a close and crowns the whole of human cognition’ (LPR
28: 1037).
Notes
1
I cite Kant from the Akademie edition by reference to volume and page number. Quotations
from Critique of Pure Reason are cited by the standard (A/B) pagination. I mostly use the
translations of the Cambridge edition of Kant’s works (Kant 1998, Kant 2000, Kant 2001 [LPR],
Kant 2003 [NE, OPA], Kant 2005 [Reflexionen]); if there has been no translation in that edition,
translations are mine. References to Kant’s unpublished Reflexionen will be given with the
28
numbers of the individual reflections (R #) provided in volumes 17, 18 and 19 of the Akademie
edition. I use the following abbreviations: LPR=Lectures on the Philosophical Doctrine of
Religion; NE=A New Elucidation of the First Principles of Metaphysical Cognition; OPA= The
Only Possible Argument in Support of a Demonstration of the Existence of God;
2
Kant criticized the Cartesian ontological argument first in NE 1: 394-5 and then in greater
detail together with the two other proofs in OPA 2: 72-5, 155-62.
3
However, the exact nature of this criticism varies among interpreters. See for example Wood
1978: 71-79, Fisher and Watkins 1998, Logan 2007: 357-61, Rukgaber 2014: 98-102, Stang
2016: 288-96, Abaci 2017.
4
This is the most controversial step in most reconstructions of the proof. See for example Fisher
and Watkins 1998: 375, Adams 2000: 432-4, Stang 2010: 292-4, Boehm 2014: 27.
5
In addition to the previous footnote, see also Wood 1978: 70-1.
6
See also Adams 2000: 427, Stang 2010: 280-1, Chignell 2012: 645-8, Yong 2014: 38-44, Stang
2016: 107-19.
7
E.g ‘The material element which is given here as standing in such a conflict is itself something
and can be thought’ (OPA 2: 77).
8
For a detailed discussion of the ontological commitments of the possibility proof see Kanterian
2017: 209-10.
9
Independently of Kant’s argument, Platonism might be an attractive theory for grounding
modal facts. See Berman 2013.
10
Paul Franks argues that there is a shift in Kant’s thought from a dismissive attitude in the first
Critique to more positive attitude in the 1786 Orientation essay (Franks 2005: 66). My
29
explanation of the regulative value of the proof implied in the former supports the view that there
is no substantive shift.
11
See Fisher and Watkins 1998: 380-4. Logan argues that this is indeed the case, that Kant’s
rejection of his own proof is based on an unjustified empiricist shift in Kant’s thought in the late
1760s (Logan 2007: 354-60). While this might explain the historical development that led to
rejection of the proof, I will show in the next section that the Critical Kant refutes the proof by
rejecting its main premise and not only its conclusion, and that he also explains the motivation
for this premise by appeal to the interests of reason.
12
Rukgaber 2014 argues that although ‘the metaphysical vision of the pre-Critical Kant is
informing his theory of the transcendental ideal’ the argument of section two ‘shares nothing
with the pre-Critical argument except the idea of the ens realissimum’ (Rukgaber 2014: 100). I
disagree, as the principle of thoroughgoing determination leads to the material substrate required
for the possibility of things qua individuals. In this I agree with Stang 2016: 292.
13
I have emended the translation by Wood and Guyer which I believe is inaccurate: ‘…and even
to presuppose these possibilities as contained in a particular original being’. The original reads:
und diese sodann, als in einem besonderen Urwesen enthalten vorauszusetzen. It is more
probable that diese refers to the possibility of the highest being and not to all the possibility of
things, both for grammatical reasons, and because it was stated before that God is the ground and
not the sum total of all possibilities, hence the latter are not contained in God. I thank an
anonymous referee for noting this peculiarity in the translation.
14
This is noted in Wood 1978: 64-6, Grier 2001: 240-1, Longuenesse 2005: 219-22, Abaci 2017:
280-2.
30
15
It should be noted that this does not violate the claim that the modal categories do not
determine anything in the object; here the presupposed actuality of the sum total of realities is
not a judgment that an object is actual but only put forth as a presupposition for the possibility of
thoroughgoing determination.
16
The term is first introduced in the Inaugural Dissertation of 1770 as the ‘the confusion of what
belongs to the understanding with what is sensitive’. In the Critique, the term is generalized for
all cases in which a principle of empirical cognition is extended beyond its boundaries, e.g.
inferring the existence of the soul from the unity of consciousness (A389, 402). See also Grier
2001: 246-7, Abaci 2017: 285-6.
17
Note that this sum total is also only an idea that cannot be given in experience, and hence
empirical cognition can only strive for complete determination but never achieve it. See Abaci
2017: 283-4.
18
E.g. spatial, temporal and categorical relations: ‘everything in our cognition that belongs to
intuition … 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)’. (B66; cf. A265/B321).
19
Longuenesse ignores the distinction between the two kinds of unity and the regulative role of
the collective unity. She thus suggests that in these passages Kant offers a critical notion of
thoroughgoing determination which can be formulated using the resources of the Analytic alone
(Longuenesse 2005: 221-2). For criticisms of this reading see Grier 2001: 237-46, Verburgt
2011: 245-52. Fisher and Watkins (1998: 392-5) also argue that the rejection of the possibility
proof is based on the distinction between understanding and reason and their different domains,
but they do not explain in detail the illusion related to it.
31
20
In a different context, Glezer (2017: 164-8) suggests a similar connection between conceptual
systematicity and noumenal reality. His ultimate position is incompatible with mine, but a full
response is beyond the scope of this paper.
21
The German term is Objekt and it is clear that in this context it is not an object of sensible
intuition but rather an object in general, thought as a thing in itself.
22
Grier 2001: 233. Abaci (2017: 287-9) agrees with Grier on this issue.
23
Grier 2001: 120, 122. As Boehm (2014: 51-2) has shown, P1 and P2 can be regarded
respectively as subjective and objective formulations of the principle of sufficient reason. This
fits well with my reading as it emphasizes that the principle of reason is not only applicable to
grounding causal series of contingent things but to any kind of unconditioned ground.
24
Stang (2016: 293-5) has a different explanation of the illusion, motivating the Ideal in terms of
principles which correspond with Grier’s P1/P2 distinction: a Logical and a Pure Principle of
Reason. The illusion stems from applying the latter to the grounds of noumenal real possibility,
so that reason supposes that there is a determinate complete set of all possible predicates.
Discussing this account is beyond the scope of this paper, but I find it compatible with mine:
noumenal real possibility is itself a problematic concept of reason since we can only think about
its ground as intelligibilia.
25
Willaschek (2018: 231, fn. 22) makes the stronger claim that section two does not at all
discuss the metaphysical error of assuming the existence of the ens realissimum, and that this
assertion comes only in section three.
26
‘Leibniz took the appearances for things in themselves, thus for intelligibilia, i.e. objects of the
pure understanding’ (A264/B320). ‘If, however, I suppose there to be things that are merely
32
objects of the understanding … then such things would be called noumena (intelligibilia)’
(A249). See also Allais 2015: 7.
27
Although OPA uses examples of empirical objects, the ground of the possibility of their
fundamental predicates are essences, hence abstract objects.
28
Willaschek (2018: 9) argues that ‘the claim that the structure of reality corresponds to that of
rational thought’ is the erroneous tacit assumption Kant identifies in speculative metaphysics in
general).
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