1. Introduction
There has been a recent upsurge of interest in Kant's The Only Possible Argument in Support of a Demonstration of the Existence of God Footnote 1 – a pre-Critical work in which Kant argues that God's existence is required to account for possibility as such. Interpreters rightly note that, far from being a defunct exercise in dogmatic philosophy, this work is of both historical and philosophical importance. Historically, it highlights Kant's abiding interest in the grounds of possibility throughout his careerFootnote 2 and forms part of a continuous argumentative thread running from Leibniz through to the later German Idealists regarding the manner in which thinkable content is to be accounted for.Footnote 3 Philosophically, The Only Possible Argument is important insofar as Kant, unlike many contemporary philosophers, does not take facts about possibility to be brute but claims rather that they require explanation, and the explanation he offers asserts that modal facts concerning possibility can be accounted for only by the actuality of a necessary ens realissimum.Footnote 4
Traditionally, interpreters have understood the possibility that Kant's argument seeks to account for as consisting of two elements. The first element of possibility is logical consistency. The positing of this sort of possibility is motivated by the view that, if something is possible, it must be (at least) logically consistent. The second element of possibility is its content. The positing of this kind of possibility is motivated by the idea that without contents nothing could stand in relations of logical consistency or contradiction. According to this broad family of interpretations, Kant's argument centres on the claim that the content of possibility (which he also identifies with the inner possibility of things) depends on the existence of God either by being the intentional object of the divine mind or by being a limited version of a corresponding divine perfection instantiated by the divine nature.Footnote 5
Yet this family of interpretations faces a serious objection in that the inference from the necessity of some ground for the content of possibility to the necessity of a single ground for it appears unjustified.Footnote 6 Take the set F of contents {C1, …, Cn}. Even if one assumes that every element of F requires some ground, there is no reason to think that they all share the same ground. Why should anyone think, for example, that the contents prime number and Caesar are both grounded in one and the same entity? Unless further conditions are stipulated, there could be different grounds for different contents. Call this the plurality objection.Footnote 7
Andrew Chignell has recently provided a new interpretation of Kant's argument which appears to be able to block the plurality objection by considering another kind of possibility – the sort of post-Kripkean metaphysical possibility familiar to contemporary philosophers which Chignell labels ‘real harmony’.Footnote 8 His reading can thus be called a real harmony interpretation (RHI for short). Put simply, two properties F and G are really harmonious if and only if F and G are capable of co-instantiation in a single object without rendering that object metaphysically absurd in the process (i.e. if and only if something can really be F & G). So, for example, the properties being human and being wise are really harmonious since it is metaphysically possible for someone (e.g. Socrates) to be a wise human. In contrast, the properties being human and being made of ice fail to be really harmonious since it would be metaphysically absurd for something to be both human and made of ice. Chignell calls the lack of real harmony ‘real repugnance’.
According to Chignell, invoking only the elements of consistency and content is insufficient to account for real harmony. Logical consistency rests on the principle of non-contradiction. But such a principle is inadequate to account for real harmony. Consider the proposition <some humans are made of ice> which expresses a real repugnance. The contents being human and being made of ice entail no formal contradictions when predicated of a thing, yet these two properties are nonetheless really repugnant. Moreover, an explanation invoking the mere existence of thinkable content is also insufficient to account for real harmony since these contents (namely, being human and being made of ice) are available, as is required.Footnote 9 As a result, Chignell contends that facts concerning the real harmony of properties can be grounded only in their actual co-exemplification (or lack thereof).Footnote 10 So, for example, the real harmony of being human and being wise is grounded in their actual co-exemplification. Likewise, the real repugnance of being human and being made of ice is accounted for by the fact that nothing co-exemplifies them.
By grounding real harmony in the actual co-exemplification of properties in a single object, Chignell's interpretation of Kant's possibility argument appears to be able to block the plurality objection (2012: 655–7). A state of affairs in which one object exemplified a property F and another object exemplified a distinct property G would be insufficient to ground the real harmony of F and G. So, for example, the fact that Socrates is human and the first snowflake of the season is made of ice does not imply that being human and being made of ice are really harmonious. Indeed, these properties are paradigm cases of real repugnance. Thus, for any set of really harmonious properties there must be a single ground for their harmony. It therefore appears that the plurality objection cannot apply to RHI. So Chignell's interpretation seems to be a substantial improvement over more traditional ones in that it can overcome an otherwise debilitating objection to Kant's argument.Footnote 11
This article will make two related claims. First, it will contend that Chignell's interpretation of Kant's argument is both textually and philosophically problematic. Second, it will argue that more traditional interpretations can overcome the plurality objection by focusing on the need to ground the content of possibility as a totality. The article will therefore proceed in two parts. The first part will raise three objections to RHI. The first objection attacks the textual basis of Chignell's reading. The next two objections undermine its alleged philosophical advantages: the second objection argues that RHI is either metaphysically unintelligible or falls prey to the plurality objection, and the third objection argues that, on Chignell's interpretation, Kant's argument is explanatorily self-defeating. The second part of the article sets forth an alternative metaphysical principle that can block the plurality objection when the possibility argument is properly formulated. It contends that, by framing the argument in terms of the totality of possibility and by adopting the principle that the relations constituting this totality require a single ground in thought, one thereby eliminates the suspicion that there might be multiple grounds of possibility.
2. Problems for the Real Harmony Interpretation
This section will set forth three difficulties for Chignell's interpretation. The first difficulty is textual and will be examined in 2.1. The next two problems are philosophical and will be examined in 2.2 and 2.3.
2.1 Lack of Textual Support
The first problem with RHI is that it lacks an adequate textual basis. The primary textual support for Chignell's reading consists of two short passages in the Only Possible Argument – call them T1 and T2. In T1, which occurs in the context of an argument that the unique, simple, immutable, and eternal ground of possibility must also contain supreme reality, Kant claims that:
[all] predicates can by no means co-exist together as determinations in a single subject … The impenetrability of bodies, extension and such like, cannot be attributes of that which has understanding and will … Now, although I concede that there is no logical contradiction here, the real repugnancy is not thereby cancelled. Such a real repugnancy always occurs when something, as a ground, annihilates by means of a real opposition the consequences of something else. (2: 85–6)
And in T2, where Kant addresses a potential objection to his previous claim (made in 2: 87–8) that the ground of possibility must have a mind, he provides a further argument for the claim that an ens realissimum must exemplify the properties of being intelligent and being volitional rather than merely derivatively grounding them:
This leaves undecided the question whether the properties of understanding and will are to be found in the Supreme Being as determinations inhering in it, or whether they are to be regarded merely as consequences produced by it in other things. If the latter alternative were the case, then it would follow that, in spite of all the excellencies manifest in the original being which issue from the sufficiency, unity and independence of its existence, as from a great ground, its nature would nonetheless be far inferior to what one must needs think when one thinks of a god. Possessing neither cognition nor choice, it would be a blindly necessary ground of all other things and even of other minds, and it would differ from the eternal fate postulated by some ancient philosophers in nothing except that it had been more intelligently described. (2: 89)
To support RHI these passages would need to show that Kant had a very specific understanding of real repugnance. According to Chignell, a set of properties can be really repugnant in at least two ways.Footnote 12 First, they can stand in a relation of predicate-cancelling real repugnance if their joint exemplification would cancel each other out (Chignell Reference Chignell2009: 172–3). So, for example, <being blown to the east at 10 mph> and <being blown to the west at 10 mph> display predicate-cancelling real repugnance since a ship equally blown in opposite directions would move in neither direction. Secondly, they could manifest a stronger subject-cancelling real repugnance if their joint exemplification not only would cancel each other, but also would require a metaphysical absurdity that would cancel the very subject that was supposed to exemplify them (Chignell Reference Chignell2009: 173). The joint instantiation of such properties would make ‘their bearer a really impossible being’ (ibid.). Subject-cancelling real repugnance is thus much stronger than predicate-cancelling real repugnance. Since real harmony is and must be defined in terms of this stronger form of repugnance, RHI needs Kant to have the concept of subject-cancelling real repugnance. T1 and T2 are thus supposed to be clear instances of Kant employing this concept.
Furthermore, to support RHI, these passages need to show not only that Kant had the concept of subject-cancelling real repugnance but also that he used it in his argument for the existence of God. As seen above, according to RHI, Kant here claims that the real harmony of two predicates can be accounted for only by their actual co-exemplification. Since logical consistency is not enough to secure real harmony, RHI portrays Kant as inferring that actual co-exemplification is required.
Yet a close reading of these passages does not support either of these claims. First, they do not support the claim that Kant had the strong notion of subject-cancelling real repugnance. When examined more closely T1 is seen to refer to predicate-cancelling real repugnance. In this passage, Kant illustrates real repugnance through the example of opposing motive forces (2: 86) and this example is most naturally understood as a case of predicate-cancelling real repugnance.Footnote 13 A subject equally pushed in opposite directions stands still; it does not cease to exist on pain of metaphysical absurdity.Footnote 14
Similarly, T2 also fails to support the claim that Kant had the concept of subject-cancelling real repugnance. When Kant claims that a being that blindly emanates the universe would ‘be far inferior to what one must needs think when one thinks of a god’ he points out a logical inconsistency between <blindly emanating the universe> and <being a supreme being>. Our concept of God as an ens realissimum (i.e. something that includes the positive perfections of intellect and will) logically contradicts our concept of something that blindly emanates reality (i.e. something that lacks intellect and will).Footnote 15 There is little motivation for interpreting T2 as a reference to the subject-cancelling real repugnance involved in post-Kripkean accounts of metaphysical possibility. Consequently, neither T1 nor T2 provides clear evidence that Kant is, in fact, working with such a concept.
Secondly, even if these passages did support the claim that Kant has the concept of subject-cancelling real repugnance, they are not located in the right place in the text to support the contention that Kant uses this strong form of metaphysical possibility in his argument, since both T1 and T2 occur only after the existence of a necessary being has already been established. These passages consider what further characteristics this necessary being would have, but are not themselves a part of the argument for its existence. Specifically, T1 answers the question of whether this being exemplifies all the possibilities that it grounds. Kant claims that it does not, since this scenario would entail a predicate-cancelling real repugnance in the divine nature and that would, in turn, contradict our concept of God as an ens realissimum.Footnote 16 T2 answers the question of whether God grounds <intellect> and <will> by exemplifying them. Kant claims that he does since these perfections are analytically contained in our concept of God. Thus, neither of these passages pertains to Kant's argument for the existence of a necessary being. They merely clarify what further attributes this being must have. Therefore, RHI has no clear textual support.Footnote 17 Ultimately the strength of the interpretation will have to rest upon philosophical considerations. But, as we will see in the next two sub-sections, RHI suffers from philosophical difficulties as well.
2.2. Kant as Spinoza
The first philosophical problem for RHI concerns its metaphysical implications. Chignell himself has argued that RHI would force Kant to accept a broadly Spinozistic view in which the divine nature is said to exemplify all possible properties (2012: 663–8). According to RHI, Kant's argument needs God to ground both the real harmony of the divine perfections (e.g. omniscience, omnipotence, omnibenevolence) and the real harmony of finite properties (e.g. being heavy, silver, rectangular, etc.). More traditional styles of interpretation could claim that God grounds the content of possibility without exemplifying the corresponding properties himself. For instance, God could ground the content finitely powerful either by thinking it or by exemplifying a corresponding divine perfection (e.g. omnipotence) from which it is derived as a limitation.Footnote 18 Traditional interpretations therefore do not have Spinozistic implications. But this is not the case for RHI since the metaphysical possibility of real harmony (whether finite or infinite) can be grounded only in actual co-exemplification. For example, consider the subject-cancelling real repugnance expressed by the proposition: Some water is xyz. The repugnance that obtains between <being water> and <being xyz> cannot be accounted for through logical contradiction since the two concepts do not formally contradict each other. Rather, according to RHI, the only way to account for their real repugnance is by noting that nothing grounds their real harmony by actually co-instantiating them. So, if God is to ground the real harmony of finite properties, he must exemplify them.Footnote 19 Therefore, Spinozism follows.
One might avoid this implication by maintaining that the real harmony of finite properties is secured by the real harmony of the infinite divine perfections. So, for example, one might think that the real harmony of finite knowledge and finite goodness is guaranteed simply in virtue of the fact that God is omniscient and omnibenevolent. But the real harmony of divine perfections does not in fact guarantee the real harmony of the finite properties derived from them. Consider again the finite properties <being water> and <being xyz>. As finite properties, their existence is grounded in divine perfections which are themselves harmonious. Yet they remain really repugnant even if their infinite counterparts are not.Footnote 20 Hence, the only way that God could ground the real harmony of finite properties would be by exemplifying them. So, according to RHI, God must exemplify not only all really harmonious infinite properties, but also all really harmonious finite properties. In this manner Kant would be forced into a broadly Spinozistic position wherein God exemplifies not only the divine perfections but also all finite properties as well.
These Spinozistic implications of RHI are doubly problematic. First, interpretative charity opposes such an interpretation. Given that Kant not only refused to accept Spinozism but at points even branded it as an example of absurdity, it is prima facie implausible to claim that it is a central component of his theory or that his theory inadvertently commits him to it.Footnote 21
Second, these Spinozistic implications present a dilemma for RHI. Given the assumption that Kant's argument is concerned with real harmony, one is forced to either deny real harmony altogether or to fall victim to the plurality objection. In light of these options it is best to simply deny the initial assumption that the argument concerns real harmony.
The first horn of the dilemma notes that, if Kant's argument is formulated in terms of real harmony, then everything is really repugnant (and thus nothing is, in fact, really harmonious). According to RHI, God, as the sole ground of real harmony, must exemplify every set of really harmonious properties. But this leads to a scenario in which God himself must be really repugnant. Consider, for example, the fact that since <redness> and <being cinnabar> are really harmonious properties, God would have to exemplify them. Likewise, since <yellowness> and <being gold> are also really harmonious, God would have to exemplify them as well. So God must be both <red> and <yellow>, and <cinnabar> and <gold>. But <red> and <yellow> are really repugnant, and so are <being cinnabar> and <being gold>. But then, per impossibile, the ground of real harmony would itself be really repugnant and therefore there would be no real possibility of anything.
Chignell notes that Kant might be able to avoid this absurdity by accepting a Spinozistic account of divine attributes (2012: 668). But this suggestion leads to the second horn of the dilemma for RHI. On a Spinozistic account, the divine nature possesses ‘causally and explanatorily distinct’ attributes that ground real harmonies (ibid.). Real harmony between properties would be grounded in their joint exemplification in an attribute, and real repugnance would be grounded in the fact that there is no attribute in which they are jointly exemplified (ibid.). For instance, one attribute exemplifies <red> and <cinnabar> and another exemplifies <yellow> and <gold>, but no attribute exemplifies <red> and <yellow>. Yet given that the attributes which ground real harmony are ‘causally and explanatorily’ cut off from one another, the inference to a unitary ground of possibility in God is undermined. On this picture there are multiple attributes,Footnote 22 each of which is explanatorily sufficient to ground the harmonies of the properties that it exemplifies. But if this is the case, there is little reason to think that there must be a single ground of possibility as such. For example, the attribute which exemplifies <red> and <cinnabar> is explanatorily sufficient to explain their real harmony. And likewise, the attribute which exemplifies <yellow> and <gold> is explanatorily sufficient to explain their real harmony. Thus, facts of real harmony do not require a single ground in an ens realissimum. Therefore, RHI has illicitly moved from the claim that there must be some ground of possibility to the claim that there can be only one such ground. One of the chief virtues of RHI was supposed to lie in its having a straightforward answer to the plurality objection. Now, however, RHI is no better off than other interpretations in this regard.
The advocate of RHI might contend that further considerations (beyond the need to ground facts about real harmony) motivate the claim that there is a single ens realissimum. In particular, one might argue that the existence of various attributes must itself be explained and that this can be accomplished only through the fact that they are attributes of a single substance. Yet this scenario would not, in fact, be coherent.Footnote 23 The most natural model for understanding how multiple attributes could be attributes of a single substance would be through the exemplification relation. According to such a model, God would ground various attributes by exemplifying them. But this model is inadequate in two regards. On the one hand, attributes, as defined by Chignell, are sets of property instances.Footnote 24 They are thus not the sorts of things that can be exemplified themselves. On the other hand, even if there were a way in which attributes could be exemplified, the problem of real repugnance in the divine nature would re-emerge. If God exemplifies both attribute A, which consists of the exemplification of <red> and <cinnabar>, and attribute B, which consists of the exemplification of <yellow> and <gold>, it looks like God thereby exemplifies <red> and <yellow> and is therefore rendered really repugnant in which case the first horn of the dilemma reappears. Consequently, RHI's seemingly straightforward account of the existence of a single ground of real harmony does not, in fact, succeed. Hence, one of the chief philosophical motivations for adopting RHI is thereby removed.
2.3 Failure to Explain
Another philosophical motivation for adopting RHI is its apparent explanatory power. In contrast to more traditional styles of interpretation, it claims to account for post-Kripkean metaphysical possibility. Yet RHI encounters a deep internal problem in this regard since it cannot, in fact, explain such possibility. RHI attempts to explain the real harmony of properties by adopting an actualist principle that ‘modal facts have their ultimate explanation in actuality [… and] fundamental modal truths have what we now call truthmakers – i.e., actual, concrete particulars that ground or explain their truth’ (Chignell Reference Chignell2009: 158). Yet the way that RHI works out this explanatory programme is problematic. As our previous discussion has shown, if RHI is to account for the real harmony of properties, it must employ the following explanatory schema:
(RH) For any two properties F and G, F and G can be co-exemplified (i.e. are really harmonious), iff they are actually co-exemplified.Footnote 25
So, for example, the reason that <being extended> and <and having the power to burn> are really harmonious while <being water> and <being xyz> are really repugnant is that the former are actually co-instantiated while the latter are not. The former can be co-exemplified because they are co-exemplified. The latter cannot be co-exemplified because they are not co-exemplified.
But this explanatory strategy faces a problem: its explanans eliminates its explanandum. RHI appears to do away with the very question of unactualized possibility that motivated the inquiry in the first place. We began by seeking to ground facts about possible, but non-actual, co-exemplification.Footnote 26 We wanted to know why, for example, it is possible for cinnabar to be fashioned into a bust of Immanuel Kant but impossible for cinnabar to be made of ice.Footnote 27 But, according to the explanatory schema (RH), if <being cinnabar> and <being a bust of Kant> are really harmonious, then they are actually co-exemplified. So, contrary to our original supposition, there really is a cinnabar bust of Kant. What began as an inquiry into the grounds of possible co-exemplification concludes with the assertion that the possible and the actual are always co-extensive. In this manner RHI eliminates the very phenomenon that it was created to account for in the first place. So not only does RHI take Kant to be concerned with a form of metaphysical possibility which he is, in fact, unconcerned with, but it also saddles him with a defective explanation of it.
The advocate of RHI might respond that even if all really harmonious properties are actually co-exemplified in the divine nature, the interpretation still leaves room for a restricted form of unactualized possibility.Footnote 28 On this construal, our questions about possibility would all have ‘within the created order’ as an implicit restriction. While we appear to ask (Q) Even though <being cinnabar> and <being a bust of Kant> are not co-exemplified, is it possible for them to be so? What we really mean is (Q′) Even though <being cinnabar> and <being a bust of Kant>are not co-exemplified in the created order, is it possible for them to be so? RHI could thereby try to preserve a robust distinction between actuality and possibility.
But there are two problems with this line of response. First, it is not clear that our questions about unactualized possibility can be paraphrased in this manner. When I utter (Q) I do not take myself to be asking (Q′). I understand myself to be asking a question about metaphysical possibility as such rather than about possibility within a limited sphere. The case is even more clear when one considers questions of impossibility. When someone asks (QI) Even though <being H20> and <being XYZ> are not currently co-exemplified, is it impossible for them to be so? We cannot plausibly interpret them as intending to say (QI′) even though <being H20> and <being XYZ> are not currently co-exemplified in the created order, is it impossible for them to be so in this order? When inquiring into impossibility we are asking not only about the impossibility of co-instantiation in the created order but also about the impossibility of co-instantiation as such, since subject-cancelling real repugnance is meant to hold unrestrictedly across loci of possible co-instantiation. Our everyday modal discourse cannot plausibly be paraphrased as restricted to a limited domain without accepting some sort of error theory.
Second, in light of the Spinozistic consequences of the (RH) schema, it does not look like the defender of RHI has the capacity to draw a firm distinction between the divine nature and the created order. Any feature or set of features by which one could individuate a created object would have to be really harmonious with that object's other features. But since this real harmony would have to be established through co-instantiation in the divine nature, God would likewise have that feature. There would thus be no way of distinguishing between the created order and the divine nature as the paraphrase defence requires. So the explanatory objection to RHI still holds. We can therefore conclude that both of the main philosophical motivations for adopting RHI prove to be untenable. RHI can neither avoid the plurality objection nor offer a satisfying account of metaphysical possibility.Footnote 29 Therefore RHI is without clear textual or philosophical support.
3. Grounding the Totality of Possibility
RHI's philosophical problems follow from its commitment to the doctrine that the metaphysical possibility of real harmony must be grounded in actual co-exemplification. It is this commitment that entails both the Spinozistic claim that God must actually instantiate all really harmonious finite properties and the problematic modal claim that possibility and actuality are co-extensive.
More traditional reconstructions naturally fare better in these respects since they are not committed to explaining post-Kripkean metaphysical possibility and therefore do not need to ground real harmony in actual co-exemplification. Given that these interpretations take Kant's argument to be concerned with grounding the logical consistency and thinkable content of possibility (which Kant identifies with the inner possibility of things), they need not be committed to the claim that God actually exemplifies all finite properties or to the claim that all possibilities are actual. For, on the one hand, one could hold to a Leibnizian model in which God grounds the content of possibility in thought. Given that one can think about properties that one does not exemplify, God's thought can ground contents which he does not instantiate. Likewise, in light of the fact that ‘S thinks that a is F’ is an intensional context, the contents thought by God need not be actual. Or, on the other hand, one might hold to a picture in which God grounds the content of possibility by exemplifying the divine perfectionsFootnote 30 and still avoid the problems that afflict RHI by maintaining that God does not exemplify finite properties. There would likewise be no need to maintain that every finite possibility was actual on this model since they would be grounded in the actuality of their perfect correlates.
But, as noted at the outset of this article, traditional styles of interpretation must deal with the plurality objection. In what follows, I will argue that one can overcome the plurality objection by formulating Kant's argument in terms of the totality of possibility and by adopting Kant's pre-Critical principle that the relational possibilities which constitute this totality themselves require grounding in a single intellect. This response to the plurality objection employs the metaphysical principle that (a) in addition to accounting for individual possibilities, an adequate theory must also account for the possible relations that obtain between those possibilities and that (b) the grounding of possible relations can occur only through a single intellect.Footnote 31 By using this principle, traditional interpretations which accept a Leibnizian account of the grounding of possibility can offer a response to the plurality objection.
The first step in responding to the plurality objection is to note that Kant's argument is concerned with the whole of possibility. While many interpretations rightly understand the argument as attempting to account for every individual possibility, they often fail to note that it also tries to account for the whole of possibility. For example, Allen Wood formulates the argument as follows:
For a certain concept to be thinkable, therefore, the realities in question must be somehow available to the mind which is to think them. Kant maintains, however, that for a reality to be thus available for thought it must be ‘given’ to the intellect through some actually existing thing in which it is to be found. (1978: 66)
When the argument is framed in terms of ‘a certain concept’ and the ‘actually existing thing’ through which it is given, it becomes susceptible to the plurality objection, since there could be multiple discrete grounds for multiple discrete contents.
Although the pedagogical utility of concrete examples tempts us to express the argument in terms of individual possibilities,Footnote 32 we should, I maintain, refrain from doing so since it undermines Kant's overall position and conceals his deeper metaphysical insights. Instead, the content of possibility that the argument tries to account for should be understood not only in terms of individual contents, but also in terms of its constituting a totality. According to this interpretative framework, we must account both for particular contents and for the fact that they together form a single domain of possibility. To see the contrast, note the ambiguity in Kant's claim that ‘all possibility presupposes something actual in and through which all that can be thought is given’ (2: 83). The claim might mean that for every particular possibility there is something actual that grounds it, but it might also mean that there is an actual ground for the totality of possibility as such. Previous interpretations have tended to reconstruct Kant's argument in light of the former reading,Footnote 33 but there is considerable motivation for taking it to involve the latter instead.
To begin, textual considerations favour this reading. In The Only Possible Argument, Kant identifies the content of possibility with ‘all the data of all that can be thought’ (2: 82) and speaks of ‘all internal possibility whatever’ (2: 83). He also explicitly draws the distinction between particular possibilities and possibility as a totality when he claims that ‘what has to be shown of all possibility in general and of each possibility in particular is that it presupposes something real, whether it be one thing or many’ (2: 79). Finally, Kant's own (allegedly inadequate) response to the plurality objection appeals to the totality of possibility. Kant argues:
Since the necessary being contains the ultimate real ground of all other possibilities, it follows that every other thing is only possible in so far as it is given through the necessary being as its ground. Accordingly, every other thing can only occur as a consequence of that necessary being. Thus the possibility and the existence of all other things are dependent on it. But something, which is itself dependent, does not contain the ultimate real ground of all possibility; it is, therefore, not absolutely necessary. As a consequence, it is not possible for several things to be absolutely necessary. (2: 84)
There is thus ample textual support for taking the argument to be concerned with grounding the totality of possibility.
Furthermore there are two broadly Kantian reasons for formulating the argument in these terms. First, the basic motivation for the argument comes from the application of the principle of sufficient reason to facts about possibility. The argument maintains that the content of possibility is neither brute nor self-explanatory but needs to be grounded in something more ontologically basic. But it is trivially true that the totality of such possibility is itself possible. Hence, the principle of sufficient reason demands that we find an explanation for the totality of the content of possibility.Footnote 34
Second, the principle of thoroughgoing determination claims that every existing object is a determinate entity.Footnote 35 According to Kant, ‘in order to cognize a thing completely one has to cognize everything possible and determine the thing through it, whether affirmatively or negatively’ (A573/B601). But a commitment to this principle thus implies a commitment to the totality of all possible properties. And, once more, the principle of sufficient reason demands that we find an explanation for this totality.Footnote 36
Once the argument is formulated in terms of the totality of possibility, one can then contend that the relations which constitute this totality can be accounted for only by invoking a single ground. This contention depends on Kant's pre-Critical metaphysical principle that the mere existence of individual possibilities is insufficient to account for the relations that obtain between them. Kant set forth this metaphysical principle in his Nova Dilucidatio – a work composed prior to the Only Possible Argument. The Nova Dilucidatio not only contains an earlier version of the possibility argument, but also provides a further elaboration of Kant's pre-Critical account of relationality which is essential to the argument's validity. In the Nova Dilucidatio Kant maintains that the mere existence of diverse substances is insufficient to account for their ability to relate to each other in a common world. Instead, he claims that a further ground is responsible for their possible relations. Kant explains as follows:
But it does not follow from the fact that God simply established the existence of things that there is also a reciprocal relation between those things, unless the same schema of the divine understanding, which gives existence, also established the relations of things to each other, by conceiving their existences as correlated with each other. It is most clearly apparent from this that the universal interaction of all things is to be ascribed to the concept alone of this divine idea. (1: 413)
Presumably this claim is motivated by the principle of sufficient reason. Suppose that two separate substances S1 and S2 can each be ‘completely understood independently’ (1: 413) of the other. S1, considered as an independent substance, would have no features from which one could derive the existence of S2 and vice versa. Now consider the determinate relational properties of S1 and S2:
R1: existing in a world with S2
and
R2: existing in a world with S1.
According to Kant the mere existence of S1 and S2 does not explain how they come to exemplify these determinate relational properties. He claims:
If, therefore, the existence of some substance or other is posited simply, there is nothing inhering in it which proves the existence of other substances distinct from itself. But since a relation is a relative determination, that is to say, a determination which cannot be understood absolutely, it follows that a relation and its determining ground can neither of them be understood in terms of the existence of a substance, when that existence is posited in itself. (1: 413)
Considered as an independent substance, S1 has no feature from which one can infer the existence of S2. But in coming to exemplify R1 it comes to bear a relation from which one can infer S2's existence. The principle of sufficient reason demands an explanation for this relation. This holds for the same steps from S2 to S1. Thus any explanation of S1 and S2's unification in a common world requires a ground beyond the ground of their mere existence. Kant claims that God, as the common cause who binds them together through the schema of his understanding, is such a ground.Footnote 37
When applied to the sphere of possibility, Kant's pre-Critical metaphysical principle allows one to block the plurality objection. The plurality objection claims that, since two (or more) beings – call them Bert and Ernie – could distributively ground the whole of possibility amongst themselves, it is not necessary to posit the existence of a single ens realissimum to ground the totality of possibility.
Yet such a scenario proves to be impossible if one accepts the metaphysical principle that the relations between individual substances cannot be accounted for by their mere existence. Rather, Kant contends that such relations can be explained only by the existence of a further ground. This contention is supported by two kinds of argument.
The first kind of argument contends that the ‘order, beauty, and perfection in all that is possible’ (2: 88) requires a single intellectual ground.Footnote 38 This type of argument is motivated by observing the existence of a conceptual order. For instance, one can note that from the fact that <Bach's Matthäuspassion is underappreciated> one could infer that <a work by Bach is underappreciated>, that <some music is underappreciated>, or that <it is possible for the world to have flawed aesthetic standards>, etc. Since this is a conceptual order, it is also an intellectual order. And Kant seems to believe that an intellectual order can be grounded only by an intellect. But it is precisely such an order that constitutes the domain of possibility. The totality of possibility is conceptually ordered in that its constituent possibilities are not fragmented, but stand together as a single space of thinkable content. In this sense, even what we would consider to be dreadful possibilities would be seen to have a certain beauty and perfection in light of their intelligibility within the whole of conceptual space.Footnote 39 Kant claims that the only way to account for this conceptually unified domain of possible thought is through the schematization of a single intellect.Footnote 40
The second kind of argument applies the principle of sufficient reason to facts about possibility. According to this type of argument the ability of disparate individuals to jointly ground the whole of possibility itself would require explanation.Footnote 41 The plurality objection maintains that Bert and Ernie can together account for the totality of possibility even though neither can do so on his own. But, for Kant, the alleged fact that Bert and Ernie can relate to each other so as to jointly ground the whole of possibility needs to be accounted for. And in the Nova Dilucidatio he contends that the simplest explanation of this possible relation would appeal to the common cause of these substances schematizing them together in thought. But then the plurality objection would itself presuppose the existence of a single ground which unites Bert and Ernie.
One might object that, even if a further ground is needed to explain the union of Bert and Ernie, this ground need not be the unique ground of the totality of possibility. Suppose, for example, that Bert intrinsically grounds one set of possibilities, Ernie intrinsically grounds another set of possibilities, and that a further ground, call it Oscar, which is not responsible for any of the possibilities grounded by Bert or Ernie, grounds the union of Bert and Ernie. On this scenario, Oscar would function as an admittedly lazy ground for the totality of possibility. As a lazy ground Oscar supports one and only one possibility: that Bert and Ernie can mutually interact. The true ground of the whole of possibility would then be the joint action of the unholy trinity of Bert, Ernie, and Oscar. Bert and Ernie would each ground half of the totality of possibility while Oscar would merely ground their possible relation. Kant's argument would therefore once more founder on the plurality objection.Footnote 42
Yet the problem of accounting for the mutual interaction of these disparate grounds emerges for this scenario as well. One must explain the alleged fact that Oscar stands in community with Bert and Ernie so as to be able to relate them. Since Oscar has been stipulated as the ground of only one possibility (namely, the possibility of the relation of Bert and Ernie), there is no fact about Oscar which explains how he can relate to Bert or Ernie. As itself an individual substance, Oscar's mere existence would be insufficient to ground the possible relational facts about him (such as grounding a set of possibilities with Bert and Ernie). But the principle of sufficient reason demands that this fact be accounted for. The community of Oscar, Bert and Ernie cannot be explained through the stipulation of a further lazy ground since that would lead to an infinite regress. A non-lazy ground is thus needed. And the most plausible candidate for such a non-lazy ground would be the common cause of Oscar, Bert and Ernie. On this scenario, the relation between a ground and the substances which it grounds is explained by the fact that the former is the cause of the latter. The community between Bert, Ernie and Oscar could then be accounted for through their schematization in the mind of their common cause. But this is precisely the role that God is supposed to play in Kant's account. So, even the alleged counter-example of the unholy trinity of Oscar, Bert and Ernie presupposes the existence of a single ground for the whole of possibility.Footnote 43 Kant can therefore offer a decisive response to the plurality objection by formulating his argument in terms of the totality of possibility and invoking the metaphysical principle that one must ground not only individual possibilities but also the possible relations between them. By appealing to divine schematization as the ground of the totality of possibility Kant is thus able to provide an account of modality that minimizes bruteness and satisfies the demands of the principle of sufficient reason.
4. Conclusion
By formulating Kant's argument in terms of real harmony, Chignell's interpretation appeared to be able to both block the plurality objection and to account for a kind of possibility not investigated by more traditional interpretations. But after further investigation, this interpretation was seen not only to lack textual support, but also to fail to have the advantages claimed for it. The adoption of a Spinozistic account of the divine attributes to ward off the threat of real repugnance in the divine nature causes the interpretation to fall prey to the plurality objection and the interpretation's explanatory schema fails to provide a plausible account of post-Kripkean metaphysical possibility.
As an alternative I have argued that Kant's focus on the totality of possibility along with his adoption of the principle that the relations between possibilities require grounding in a single intellect allows one to block the plurality objection while avoiding the problems that beset RHI. Such a response has a clear textual basis, does not require a Spinozistic account of the divine nature and need not deny the existence of unactualized possibilities. Though it does not provide an explanation of post-Kripkean metaphysical possibility, this interpretation nonetheless warrants further contemporary attention. Kant rightly observed both that atomic modal facts and the relations that obtain between these facts need to be explained. Given the widespread appeal to modal principles in contemporary analytic philosophy, philosophers working within this tradition ought to follow Kant's example and provide an appropriate metaphysical account of these facts. Such an account would not only explain the existence of particular modal principles, but also the fact that these principles relate to one another in a rationally explicable order. Though Kant's explanation draws on a strong and controversial metaphysical doctrine (namely, that relations are grounded in thought), it nevertheless has the benefit of minimizing modal bruteness and explaining relational facts between possibilities. Thus, the standing challenge that Kant's Only Possible Argument presents to contemporary philosophers who are dissatisfied with its explanation of modality is to provide a rival account.Footnote 44
