I. Kant and the Theological ‘Tradition’

Kant as a Christian thinker remains controversial to this day. Discussions regarding Kant and the theological ‘tradition’ raise several complications, namely what do we mean when we talk about the theological ‘tradition’ in relation to Kant. More challenging, is the fact that elementary misunderstandings of Kant's philosophical thought are still common, and serious Kant scholars often disagree about interpretations. Therefore, to avert the thorny question regarding tradition, when I speak of Kant and the theological tradition, I am specifically speaking of the Pietist tradition which Kant received, from thinkers such as August Hermann Francke, Christian Thomasius, and later Martin Knutzen. On the other hand, there is fortunately not the same level of controversy surrounding the philosophical tradition which Kant was associated with. Nonetheless, for clarity, when I speak of the philosophical tradition in regard to Kant, I am specifically speaking of the philosophical tradition he received from thinkers such as Christian Wolff, Alexander Gottlieb Baumgarten, and Christian August Crusius.

Kant's intellectual formation was saturated in the categories of rationalist theology, which was heavily indebted to the scholastic tradition.Footnote ¹³ Despite this, Kant does not himself read scholastic sources, although, he surprisingly makes several fleeting references to Anselm throughout his life. While there is always a certain amount of ‘thin ice’ under our feet when we approach Kant's lectures, in 1783 Kant is said to have directly referred to Anselm as being ‘the first to try to establish the necessity of a highest being from mere concepts, proceeding from the concept of an ens realissimum’.Footnote ¹⁴ To that end, in a Reflexionen (dating from as early 1780s) Kant refers to Anselm's ‘ontotheology’.Footnote ¹⁵ And in 1791 Kant writes of Leibniz adding to or supplementing Anselm's argument.Footnote ¹⁶ However, Kant's most detailed comment on Anselm is from 1794, where he identifies Anselm as a ‘Parisian Scholastic’, who ‘first put forward the argument developed by Descartes and Leibniz’.Footnote ¹⁷ Although Kant's references to Anselm are ephemeral, they still substantiate that Kant was to some extant aware that Anselm was the first to attempt to formulate such an argument and that Leibniz developed it. Another important piece of evidence is John Henry Stuckenberg's report that Kant delivered a course of lectures on ‘criticism on [sic] the proofs of the divine existence’ prior to 1763.Footnote ¹⁸ Again, neither did Anselm or Anselm's argument feature in these lectures.

Kant's direct references to Anselm raise two historical hurdles. First, the nature and the extent of Descartes acquaintance with Anselm's work is controversial,Footnote ¹⁹ and the same can also be said about Kant. On the one hand, Ian Logan argues that ‘it is clear from the lack of serious discussion of Anselm, that Kant was not directly acquainted with Anselm's work’.Footnote ²⁰ Logan further posits, that it is obvious that ‘Anselm's argument as an ontological argument (in the sense of that of Descartes and Leibniz) was based on the reports of others who were little or no better acquainted with Anselm than Kant himself’.Footnote ²¹ However, on the contrary, Gregory Robson and Chris Heathwood maintain that Kant was not only well aware of Anselm's proof albeit, Descartes’ revival of it in modified terms, but that ‘Kant had in mind at the time of his writing the broader line of ontological proofs that ran from Anselm to Leibniz’.Footnote ²² This is a decisive point, but one that seems misleading. How could Kant have Anselm's argument in mind, when Anselm's argument is not only distinctly different to that of Descartes and Leibniz's, but Kant's knowledge of Anselm's argument is nebulous?

Despite Robson and Heathwood's suggestion that both Descartes and Kant were well aware of Anselm's proof, there is resounding historical evidence against them. The first being, the initial dilution of Anselm's proof via Bonaventure, who was teaching at the University of Paris at the same time as Aquinas, and who was the first thirteenth-century thinker to pay serious attention to Anselm's ontological argument.Footnote ²³ Here, Aquinas’ criticism of Anselm's proof is most likely directed towards Bonaventure's ontological argument,Footnote ²⁴ rather than Anselm's. Second, most seventeenth-century philosophers were only familiar with Anselm's proof via Thomas Aquinas’ paraphrase in the opening sections of the Summa Theologiae.Footnote ²⁵ Third, and astoundingly, it is this brief paraphrase from Aquinas that Descartes receives five centuries later through the Dutch Thomist theologian, Johannes Caterus, who accuses Descartes of borrowing it.Footnote ²⁶ Fourth, due to the prominence of Aquinas’ Summa Theologiae in the seventeenth-century, and the obscurity of Anselm-Gaunilo's exchange, Aquinas’ passage from the Summa, not the Proslogion, serves as the backdrop for Descartes’ argumentum cartesianum.Footnote ²⁷ Even more problematic for Robson and Heathwood's thesis is the arduous work historians have carried out on the unstated targets of Kant's various criticism; nowhere in these works does Anselm or Anselm's argument feature.Footnote ²⁸

II. The Beweisgrund

Kant, in Beweisgrund searches for, and claims to postulate, a proof in support of a theistic God. He affirms that his ‘procedure will be like that of someone who is searching for a definition’.Footnote ²⁹ The search for such a proof is an inherently theological project, beginning with Anselm, who ‘began to wonder if perhaps it might be possible to find one single argument that for its proof required no other save itself, and that by itself would suffice to prove that God really exists’.Footnote ³⁰ Despite undertaking similar theological projects, Anselm does not make his claim in the mode of an analytic philosopher searching for a definition, but in the mode of a pastor trying to provide resources for spiritual translation. Furthermore, Kant affirms that his argument is ‘a proof which can be conducted entirely a priori’. That is, it ‘presupposes neither my own existence, nor that of other minds, nor that of the physical world’.Footnote ³¹ Kant's argument, or rather his proof, is of the ontological kind, even though he had not yet introduced this term (ontologischer Beweis) until the Critical period. More importantly, Kant's proof is based on the putatively a priori truth that ‘something is possible (etwas möglich ist)’.Footnote ³²

The comment that has fostered the most critical attention in Beweisgrund, comes in Kant's maxim that ‘existence is not a predicate’ (Das Dasein ist gar kein prädicat). This statement has been taken to be the most successful rejection of the ontological argument. I will make it clear that such an observation is surprising in relation to both Kant and Anselm. In the process of apparently rejecting the ontological argument in Beweisgrund, Kant's proof at the same time subscribes to his own criticism that existence is not a predicate. What we will see, is that Kant is essentially able to clear this conceptual, or rather semantic, hurdle because his proof does not merely move from a conceptual ground (in intellectu) to its analytical result (in re). Rather, in his proof, ‘the divine existence as a ground is concluded from the possible as a result’.Footnote ³³ Here, Andrew Chignell becomes a helpful point of orientation to understand how Kant's argument is both synthetic and a priori:

Chignell's description is somewhat similar to Anselm's analogy of the painter. For the painter, the starting point is a priori (in intellectu) and then it regressively culminates with the conceptual breaching the real (the painting actually existing). In this instance, much like Kant, Anselm substantiates that something can actually exist a priori as well as in reality. In this regard, Kant's proof goes beyond the Cartesian argument, in that Kant does not assume that the metaphysical lacuna, from the conceptual to the real, is easily overcome by adding the predicate ‘perfect’ to God. For Kant, the additional modal ‘possible’ stands in for this metaphysical movement to draw a logical a priori conclusion. Interestingly, this results in the proof not ‘violating Kant's later strictures against analytic existence-claims; it is thus structurally similar to the arguments he will call transcendental deductions’.Footnote ³⁵ This observation becomes profoundly important for my subsequent discussion of the argument in Kant's Critical period.

When Kant says that ‘existence is not a predicate’ he understands this in two ways. First, Kant elucidates that there is no ontological or semantic advantage of tacking-on ‘existence’ as a predicate to something. Kant gives the following example:

What Kant means by this, is that when I hear the word ‘omnipotent’ I understand its meaning and I simply apply its meaning to the concept of God. Consequently, all I am determining is that I know what ‘omnipotence’ means, rather than offering a probative conclusion that God is actually this or that (‘I am merely speaking of the predicates of that thing’).Footnote ³⁷ Second, ‘nothing more is determined by a possibly existent thing than an existent thing’.Footnote ³⁸ This is Kant's initial movement in favour of the modal principle ‘possibility’. I will not discuss here Kant's understanding of ‘possibility’ as it is the focal point of discussion in the following section.

As a result of Kant's criticism, existence cannot be applied to God. As Kant explains:

While this is a semantic thesis, Kant's main idea here is that ‘a sentence ascribing extension to something is meaningless, rather than truth-valued’.Footnote ⁴⁰ What this means is that the predicate ‘existence’ should only be one predicate in a long list of predicates, or rather attributes which pertain to God (these can be understood in terms of non-intentional predicates). If one is to claim that God ‘exists’ (extension), this does not posit anything about God's actual existence, but is instead a reductive sentence that misaligns subject and predicate. The predicate ‘exists’ does not tell us anything about the nature of the subject it is being syntactically correlated to. As a result, by applying the predicate ‘existence’ to a subject, namely God, it does not tell us anything about the subject God or God's existence, but only about the predicate itself. In short, existence cannot stand in as a logical predicate for other predicates. Rather, these predicates must be posited relative to the subject (God), not existence. Consequently, it is this understanding which provides the framework for the identification of God as the ens realissimum. The being that essentially ‘exemplifies a maximal version of every fundamental positive predicate of reality (realitas) which can be possessed by anything else’.Footnote ⁴¹ As God states, ‘sum qui sum’ (Exodus 3:14). God exists in such a way that his insatiable nature is implied in his existence. God's essence either contains existence as a component or contains predicates that logically entail his existence.Footnote ⁴²

What is most striking about Kant's criticism of the ontological argument, both in Beweisgrund and the first Critique under the titled ‘On the impossibility of an ontological proof of God's Existence’Footnote ⁴³, is that the standard criticism of the ontological argument (existence is not a predicate) originates from Kant's own attempt at proving such an argument to be valid. Even more interesting is that Kant's argument was rejected and rarely discussed as a serious contender to the popular Baumgartian argument of the time. Moses Mendelssohn severely criticised Kant's argument, suggesting that it neither supplanted Baumgarten's argument, nor contributed to the argument in any way.Footnote ⁴⁴ Mendelssohn's criticism may be the reason owing to the obscure status that Kant's argument has held in the history of the ontological argument.

III. Possibility and Necessity

Before Kant reaches his conclusion that ‘this necessary being’ (Das nothwendige Wesen) ‘is a God’ (ist ein Gott)Footnote ⁴⁵ he first outlines two central concepts in his argument. The first is the concept of possibility (Möglichkeit), and the second is the concept of absolute necessity (absolute Notwendigkeit). In this section, I will only provide a cursory account of these concepts as several commentators have already meticulously reconstructed them; it is, thus, not my intention to offer new avenues of interpreting Kant's argument. Instead, I will follow in the popular trend of modal logic.

Kant has a bifurcated understanding of possibility. For Kant, there is logical possibilityFootnote ⁴⁶ and material possibility.Footnote ⁴⁷ Here, I will bracket material possibility because, for Kant, God's existence is a material possibility. Material possibility according to Kant always ‘presupposes something real’.Footnote ⁴⁸ However, Kant draws a further distinction, claiming that:

1. (1a) The possible can only be thought insofar as it is itself real, and the possibility is given as a determination existing within the real (a fiery body)

Or

1. (1b) It is possible as a consequence through another existence.Footnote ⁴⁹

Here, possibility is understood as either a consequence (2b) or a determination (2a). What Kant means by this is that a possibility, which has not yet arrived at a certainty (something real), still has the material possibility to arrive at a certainty (something real). In line with this logic, Kant then asserts that we must accept the statement, ‘it is a possibility that a necessary being exists’, as a reality. With this understanding in mind, a possibility can necessarily be a real thing, or a true statement (truth-maker). Kant then deduces that ‘if something is possible, there exists a ground of this possibility’.Footnote ⁵⁰ On this point, Nicholas Stang correctly articulates that when Kant talks about ‘a ground of possibility’ (Grund der Möglichkeit) ‘he is referring to God's unlimited powers: the infinite powers of God are possible because they are actually instantiated by God’.Footnote ⁵¹

One of the central concepts in Kant's Beweisgrund is the concept of ‘absolute necessity’ (Absolute Notwendigkeit). According to Kant, absolute necessity is the notion that all possibility must be grounded in a single necessarily existing substance: ‘it is, indeed, an argument derived from the internal characteristic mark of absolute necessity’.Footnote ⁵² Before continuing, it is important to be in a position where we have a comprehensive understanding of Kant's definition of absolute necessity:

1. (2a) It is absolutely necessary that p just in case not-p cancels all possibility (law of non-contradiction).

Which should be understood as

1. (2b) It is absolutely necessary that p just in case, were it the case that not-p, nothing would be really possible.

This directly entails that:

1. (2c) For any x if x exists, x exists absolutely necessarily just in case were x not to exist, nothing would be possible.Footnote ⁵³

In short, if a necessarily existing being did not exist necessarily, nothing would be possible.

While Kant later identifies absolute necessity with God, he does not do this until the concluding remarks of the second section of Beweisgrund. Up until the final remarks, Kant's ‘Being’ is simply a necessary being, not the Christian monotheistic God. However, Kant's proof of the existence of a necessary being segues into proof that there is a unique being that exists absolutely necessarily:

In modal terms:

What this means, is that the necessary being is logically grounded in the essence of existence and thus entails all predicates as the ens realissimum. From this understanding, we arrive at two conclusions. First, according to Kant, absolute possibility exists: ‘all possibility presupposes something actual in and through which all that can be thought is given’.Footnote ⁵⁶ Second, absolute necessity actually exists, and this means that something real is possible. Because something real is possible—this means it can be logically inferred that it is possible a necessary being exists necessarily. It is key here, to understand that Kant's concept of absolute necessity and possibility are not mutually exclusive, but they are synonymous because for Kant the ‘necessary being contains supreme reality’Footnote ⁵⁷ (Das nothwendigige Wesen enthält die höchste Realität). Furthermore, once Kant establishes that this necessary being is ‘unique’, ‘simple’, ‘immutable’ and ‘eternal’, ‘supreme reality’ (enthält die höchste Realität), and ‘a mind’,Footnote ⁵⁸ he then identifies this existent necessary being as God:

As I will make clear in a later section, such an understanding of God and God's existence is consistent with Anselm's identification of God as ‘something than which nothing greater can be thought’.

IV. The Proslogion and the Beweisgrund

Commonly attributed to Anselm and Kant, is the perfect being argument, which Graham Oppy articulates in the following terms:

1. (1) God is a being which has every perfection. (Definition)

2. (2) Existence is a perfection. (Premise)

3. (3) (Hence) God exists. (From 1, 2).Footnote ⁶⁰

The perfect being argument, sets out to offer a proof that God has all perfections, as well as showing that existence is a perfection (ens perfectissimum). However, this is not an argument sustained in Anselm’s or Kant's texts. In the Beiwsegrund, Kant describes the necessary being as: ‘unique’ (einig), ‘simple’ (einfach), ‘immutable and eternal’ (unveränderlich und ewig), ‘supreme reality’ (enthält die höchste Realität), and ‘a mind’ (ein Gesit).Footnote ⁶¹ In the Proslogion, Anselm writes that God is: ‘life’ (Vita), ‘wisdom’ (sapientia), ‘truth’ (veritas), ‘goodness’ (bonitas), ‘happiness’ (beatitude), ‘eternity’ (aeternitas), and ‘true good’ (omne verum bonum).Footnote ⁶² While these lists of attributes are relatively traditional in both Anselm and Kant's respective contexts, Anselm's omission of the predicate ‘perfection’ or ‘most perfect’ (perfectum; solistimus) is interesting. Nowhere in the Proslogion does Anselm identify God with ‘perfection’. Kant, like Anselm, omits the predicate ‘perfection’ when talking about God. Kant articulates that: ‘Nowhere in any of the arguments belonging to my proof and presented thus far has mention been made of the expression perfection’ (vollkommenheit).Footnote ⁶³ This is because Kant ‘came to notice that the expression ‘perfection’ in some cases deviated fairly widely from the proper sense of the term because of the uncertainty which is inherent to all language’.Footnote ⁶⁴ Such an understanding marks Kant's earliest rupture with the rationalist ontological argument, which places a significant emphasis on the relation between God and perfection.Footnote ⁶⁵

Besides the predicates already noted, Anselm does not merely posit that God exists most truly, but that God ‘has existence’: ‘You among all things have existence most truly, and therefore most greatly; for whatever else exists has existence less truly, and therefore less greatly’.Footnote ⁶⁶ According to Anselm, to ‘exist’ and to ‘have existence’ can be considered two very different metaphysical statements, for human beings have existence less truly in comparison to God. For Anselm, God does not simply exist, both temporally and spatially, but rather God embodies existence as a divine power.Footnote ⁶⁷ Anselm further reinforces this divine capability in God, stating that:

According to Anselm, God has neither ‘past nor future existence but only present existence’ and nor can God ‘be thought not to exist at any time’.Footnote ⁶⁹ Here, Kant is in agreement with such an understanding of God when he claims that ‘it's non-being is absolutely impossible, and so too, therefore, are its coming-to-be and its passing-away’.Footnote ⁷⁰ From these passages it is evident that Anselm's description of God and God's relation to existence and reality resembles Kant's identification of God as supreme reality (enthält die höchste Realität) and the ens realissimum. For Kant, ‘all realities are attributed indiscriminately as predicates to God or to the necessary being’.Footnote ⁷¹ In more detail Kant writes, ‘not only is all other reality given through the necessary being as its ground, but also that the greatest possible reality capable of being contained in a being as a determination inheres in the necessary being’.Footnote ⁷² Again, Kant reinforces the notion that God does not simply exist, but contains supreme reality: ‘such a being is, therefore, the most real of all possible beings, for all other beings are only possible through it alone’.Footnote ⁷³ Kant's statement shares a striking similarity to Anselm's claim: ‘But clearly, whatever You are, You are not that through another but through Your very self. You are therefore the very life by which You live’;Footnote ⁷⁴ in Kantian terms God is the ‘complexus aggregatum of all realities’,Footnote ⁷⁵ expressed as the ens realissimum.

From these passages we can observe that for Anselm and Kant the ens realissimum is irreducibly important, whereby both authors strongly maintain that ‘all other substances only exist in dependence upon God’, this includes reality itself.Footnote ⁷⁶ Furthermore, both authors adopt analytical examinations of the relationship between predicates, God, and existence to postulate that God must have the Ground of Himself within Himself. While Kant claims that ‘existence is not a predicate’, in the same vein he substitutes the syntactic position of the predicate ‘existence’ for the modal ‘possibly’, resulting in his ontological argument relating synonymously to the notion of God's existence by way of possibility. Furthermore, both Anselm and Kant hypothesise that the notion of being and reality is intrinsically posited in God; that is to say, God does not simply exist, but rather God is existence and reality. Such a reading of Anselm's Proslogion alongside Kant's Beiwsgrund reveals that Kant and Anselm identify what God is in a very similar way. More importantly, by focusing on the entirety of the Proslogion what emerges is Anselm's understanding and identification that God does not depend on existence being a predicate. When Anselm states, ‘we believe You to be something than which nothing greater can be thought’ nowhere in this statement does Anselm require existence to be a predicate. What Anselm does require, as does Kant, is that ‘all reality must either be given as a determination in the necessary being, or it must be given through the necessary being as through a ground’.Footnote ⁷⁷ As a result, God must necessarily exist, and therefore, God in these terms Anselm would understand as the ens realissimum.

V. The reductio and the Laws of non-contradiction

Kant and Anselm both adhere to the rhetorical argumentative device, the reductio ad absurdum, to reveal the logical absurdity in the statement ‘that nothing at all exists’. For Anselm this is articulated in the following:

And for Kant:

If these propositions can be thought not to exist, then this understanding or concept is not referring to T or I. Here, Anselm draws an epistemic distinction between the thought of an object and the understanding an object; for Anselm these are two very different concepts. Anselm articulates, ‘for in one sense a thing is thought when the word signifies it is thought; in another sense when the very object which the thing is understood’.Footnote ⁷⁸ Essentially what this means is that God can be ‘thought’ not to exist, but God cannot be ‘understood’ not to exist. This is because, ‘no one, indeed, understanding what God is can think God does not exist’.Footnote ⁷⁹ It is important to bear this in mind when navigating Anselm's reductio; one must first truly understand, not just think that God is ‘something than which nothing greater can be thought”’.

Anselm and Kant further maintain, that it is logically impossible to claim that God does not exist because ‘all other reality is given through the necessary being as its ground’.Footnote ⁸⁰ As a result of this, actuality is reality, and actuality and reality are the greatest which can be thought, as made clear by Anselm, when he states that it is greater to exist in reality than simply the mind. Therefore, it is conclusive that premise I and T are actual, and it would be absurd to deduce that I and T do not exist on the basis that if I or T can be thought not to exist than I and T are not the same as I and T but are something else entirely, X and Y. As a result, both Anselm and Kant's premises, I and T, are determinable by logic, and from this logic it can be inferred that premise I and T can be identified with God. Here Anselm informs us that, ‘whoever really understands this [T] understands clearly that this same being so exists that not even in thought can it not exist. Thus, whoever understands that God exists in such a way cannot think of Him not existing’.Footnote ⁸¹ What Anselm means by this is that ‘God is indeed proven to exist most truly and maximally’,Footnote ⁸² but this verification depends on premise T. It is not a ‘necessity’, as Kant maintains, nor is it a definition. To that end, Anselm also rejects Gaunilo's misrepresentation of his formula as ‘the most excellent of all things’, since, as he says in Reply 5: ‘For “greater than everything” does not have the same force for the purposes of proving that what is spoken of exists as “something than which nothing greater can be thought”’.Footnote ⁸³

Anselm and Kant also emphasise the linguistic importance of the copulative ‘is’. For Anselm and Kant, the copulative ‘is’ connects the subject with a predicate, thus establishing the subject’s or object’s relation to our thinking or understanding. However, in Anselm's case the ‘is’ in premise G is not a predicate, such as ‘omnipotent’, ‘omnibenevolent,’ or ‘omnipresent’, but rather a complex strand of predicates, much like in Kant's argument. More importantly, this results in Kant's central criticism of the ontological argument, (existence is not a real predicate of a thing), having no consequence on Anselm's ontological argument. Anselm does not apply the predicate ‘existence’ to God. Interestingly, and largely undeveloped by Plantinga, is the notion that Anselm and Kant's shared understanding and identification of God lies in the existential ‘is’. The existential ‘is’ for Anselm and Kant does not add a new predicate to the subject, God. Lewis White Beck articulates this notion when he suggests that ‘this is mainly because in theological terms the subject of God can only be understood outside of all simple predicates’.Footnote ⁸⁴

The way in which Anselm and Kant examine objects functions as a crucial point of interest. Anselm claims that, ‘it is one thing for an object to exist in the mind, and another thing to understand that an object actually exists’.Footnote ⁸⁵ Similarly, Kant poses the question, ‘Can it properly be said that there is more in existence than there is in merely a possible existent thing?’Footnote ⁸⁶ While Kant substitutes the word ‘mind’ for ‘a merely possible thing’ both propositions attempt to establish the grounds upon which something can exist, thus deducing that existence in reality is greater than existence in the mind. Here, Kant suggests that ‘more is posited through an existent thing than is posited through a merely possible thing’,Footnote ⁸⁷ which is profoundly similar to Anselm's proposition that it ‘is greater for something to exist in reality than solely in the mind’. In this instance, both authors are in agreement that it is greater for something to exist in reality than solely in the mind. Central to Kant's understanding of God is the idea that there is a presupposition that the totality of reality and existence are synonymous with God.

When Kant talks of the unanalysable concept of existence it has an intrinsically divine nature, a nature beyond our physical understanding of it. Nonetheless, while the unanalysable concept of existence lies beyond human beings’ cognitive capabilities, this does not matter, because it is sustained by a single infinite being, which is characterised as God, whose existence also lies beyond our faculty of cognition. Despite this absence of evidence sufficient for knowledge of God's existence, or non-existence, this should not be taken as an argument for atheism or agnosticism. For Kant finds it ‘providential’ that God has not permitted such knowledge. Kant even tells us that we should ‘thank heaven’ that ‘our faith [Glaube] is not knowledge: For divine wisdom is apparent in the very fact that we do not know but rather ought to believe that a God exists’.Footnote ⁸⁸ Evidently, this leads Kant towards a metaphysics that unequivocally affirms there is a naturally divine telos in the world brought into existence by God. In contrast to Anselm, who believes that this divine telos is embedded deep within an individual's intuition, Kant understands it to be ingrained in existence as a thing-in-itself (Ding an sich).