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Reframing ‘natural theology’: Karl Barth, Emil Brunner and Ludwig Wittgenstein’s logical machine

Published online by Cambridge University Press:  15 October 2025

Ed Watson*
Affiliation:
Yale University, New Haven, CT, USA
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Abstract

This paper broaches ‘natural theology’ in terms of the conceptual systems through which revelation is understood, as opposed to questions regarding the sources of revelation. I do so by analysing Barth’s rejection of natural theology in terms of what it can mean to treat a logic of prior possibility as determining what revelation’s conditions of possibility must be. I begin by reading Emil Brunner’s ‘Nature and Grace’ alongside Ludwig Wittgenstein’s reflections on mathematical necessity in order to show that Brunner’s thinking of possibility subordinates the necessities of revelation to what Wittgenstein calls ‘the logical machine’. I then argue that Barth’s rejection of natural theology involves rejecting the workings of this machine and so rejecting the axiomatic force of prior possibility for theology. I conclude by tracing two consequences of this rejection, one related to creativity, the other to political crisis.

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A great deal of ink has been spilt over Karl Barth’s rejection of ‘natural theology’, both in terms of whether this rejection is warranted and in terms of what natural theology is.Footnote 1 For the most part, this ink has focused on whether Christians can treat things other than Jesus Christ as sources of revelation, whether this be the natural world, nation, race, culture or any other class of phenomena that we treat as matters of ultimate concern. This focus makes a great deal of sense, not least because Barth typically devotes his own attention to questions of where revelation is to be found. As Keith Johnson succinctly puts it, Barth ‘defines “natural theology” as any approach to dogmatics in which claims about God are grounded on an account of divine revelation other than God’s revelation in Jesus Christ’.Footnote 2 To talk about natural theology is just to talk about sources of revelation.

Barth also offers another definition of natural theology, however, one that is interwoven with but distinct from the definition that Johnson traces. In his ‘Nein!’ to Emil Brunner, Barth writes that ‘by “natural theology” I mean every (positive or negative) formulation of a system which claims to … interpret divine revelation, whose subject … differs fundamentally from the revelation in Jesus Christ and whose method therefore differs equally from the exposition of Holy Scripture’.Footnote 3 This definition is certainly concerned with revelation – but it does not centre on the character or the sources of revelation. It centres on the subjects of the systems through which we seek to interpret revelation, subjects which may or may not be treated as revelatory, but which are nonetheless used to determine the meaning of what is revealed. Natural theology here is not just a matter of where God’s Word is to be found. It is also a matter of what we take as fundamental when formulating the systems according to which we understand the revelation of that Word.

This paper analyses Barth’s rejection of natural theology in terms of rejecting a system of thought grounded in the principle that something can only take place if it is already possible. More specifically, I argue that, for Barth, this principle cannot be thought of as determining the conditions of divine revelation; Christian theologians must instead be willing to re-conceive ‘possibility’ in light of the idea that God creates possibility ex nihilo in the act of revelation. I begin by setting Emil Brunner’s ‘Nature and Grace’ alongside Ludwig Wittgenstein’s reflections on mathematical necessity in order to show that Brunner’s thinking of ‘prior possibility’ subordinates the necessities of revelation to what Wittgenstein calls ‘the logical machine’. I then argue that Barth’s rejection of natural theology involves rejecting the workings of this machine and so rejecting the axiomatic force of prior possibility for theology. I conclude by tracing two consequences of this rejection, one related to creativity, the other to political crisis.

My purpose is twofold. First, I aim to expand our understanding of ‘natural theology’ to encompass questions of how we form the things with which we think, as well as questions of where we can find revelation. My hope is that this will support theologians in the work of articulating how doctrinal commitments can inform possibilities of meaning. Secondly, I aim to broach Barth’s rejection of natural theology in a way that empowers creativity in the face of impossibility. My hope is that this will illuminate one of the ways in which theologically re-conceiving ‘possibility’ can play some part in changing what is possible, especially in times of political crisis. After all, alongside matters of theological principle, the vehemence with which Barth argued against natural theology was motivated by his conviction that it leads Christians to accept fascism. One need not be a natural theologian to become a Nazi; Barth nonetheless saw Naziism as a natural consequence of natural theology.Footnote 4 Any rejection of natural theology should thus be pursued with an eye toward rejecting the limits that fascist authoritarianism seeks to impose on possibility.

Brunner and Wittgenstein

Emil Brunner published the first edition of his ‘Nature and Grace’ in 1934 against the backdrop of Adolf Hitler’s rise to power. Whilst claiming unwavering solidarity with Barth’s assertion that Jesus Christ is the sole source of God’s revelation, Brunner argues against his compatriot’s recently hardened conviction that Christians must therefore deny any ‘point of contact’ in virtue of which it is possible for humans to receive that revelation.Footnote 5

Brunner offers a variety of more and less substantial grounds for this argument, ranging from his interpretation of Calvin to his understanding of the orders of creation. At root, however, the force of his account depends on the inference that if humans are to know God, then there must be something about humans that makes our knowledge of God possible, even if just ‘the purely formal possibility of [our] being addressed’.Footnote 6 As Trevor Hart puts it, Brunner argues that ‘God’s grace must make contact with something, and therefore there must be something with which contact can in fact be made in sinful human nature’.Footnote 7 After all, ‘the Word of God could not reach a man who had lost his consciousness of God entirely’.Footnote 8 Some possibility for revelation must therefore rest in humans.

Brunner’s argument here hinges on the principle that if something happens, then it must have been possible for that thing to have happened. If I speak the word ‘fish’, for example, it must have been possible for me to speak the word ‘fish’; if another person understands what I say, then it must have been possible for them to understand me. This possibility must then exist in the capacities that I and my interlocutor possess by virtue of our having lungs, larynxes, eyes, ears and nerves, not to mention the synthetic faculties of imagination, reason and understanding. By the same token, if humans know God, then it must have been possible for humans to know God, and this possibility must rest in some feature of humanity in virtue of which they can receive this knowledge. Even if this possibility does not rest in some ‘capacity’ on our part, still the fact that God’s grace makes contact with us entails that there must be something in us that makes this contact possible. Brunner articulates this ‘something’ in terms of ‘the formal imago Dei, which not even the sinner has lost’,Footnote 9 understood in terms of a ‘capacity for words and responsibility’.Footnote 10 This particular vision of a point of contact for revelation is less significant, however, than the fact that Brunner’s argument for this vision rests on the principle that if something takes place, then it must have been possible for that thing to have taken place, and if it is possible for something to have taken place, then this possibility must ‘exist’ in the relevant objects prior to the occurrence of the event.

Brunner’s reasoning here is intuitive, almost to the point of being undeniable.Footnote 11 Indeed, the idea that occurrence depends on prior possibility has the aspect of tautology – we typically use the claim ‘x is possible’ to mean that the conditions for x’s occurrence already exist, or that the conditions for these conditions exist, and so on ad infinitum. Even and especially when talking about God, it can as such feel as if we must treat the principle of prior possibility as a condition of meaningful thought, on pain of incoherence. Insofar as this is true, it is therefore ‘impossible to deny this point of contact of divine grace, i.e. it is possible to do so only by a misunderstanding’.Footnote 12 For all of its intuitive force, however, treating this principle of prior possibility as an axiomatic law of thought has metaphysical implications of great theological consequence, implications that can be sounded out by setting Brunner’s reasoning alongside Ludwig Wittgenstein’s reflections on mathematical necessity.Footnote 13

Wittgenstein’s Remarks on the Foundations of Mathematics might seem a world away from questions of revelation and natural theology. Scribbled down sometime during 1937–38, and so situated in the context of Nazi Germany’s territorial expansion and intensifying antisemitic violence, Part One of these remarks nonetheless comprises an uncompromising interrogation of the logic that animates Brunner’s natural theology.

This section of the Remarks begins with Wittgenstein’s self-critical curiosity as to why mathematicians, logicians and philosophers tend to think of the steps in a mathematical or logical series as necessarily predetermined. If I take a series as simple as ‘2, 2, 2, 2, 2, 2 …’ for example, and then assert that this series must be continued according to the rule ‘+ 0’, it does not merely seem necessary for me to write 2 at the 2025th step in the series – the correctness of this step seems to have been predetermined by the formula in an order of time entirely distinct from that in which the step is actually taken.Footnote 14 The fact that I can never write ‘3’ as the next step in the series has been determined for all eternity by the meaning of the rule ‘+ 0’.

Wittgenstein is not here arguing that ‘3’ would in fact be a valid continuation of the series ‘2, 2, 2, 2, 2’. He is concerned with understanding how we come to treat the necessity of mathematical and logical thought as if it were grounded in a kind of conceptual predestination. To this end, he first focuses on how we are trained to think with mathematical symbols, reflecting on the fact that counting, for example, ‘is a technique that is employed daily in the most various operations of our lives. And that is why we learn to count as we do: with endless practice, with merciless exactitude; that is why it is inexorably insisted that we shall all say “two” after “one”, “three” after “two” and so on’.Footnote 15 We learn to count by always relating the sign ‘1’ to the sign ‘2’ (then ‘2’ to ‘3’, ‘3’ to ‘4’ and so on) in the same way, irrespective of context or contingency. In this, we learn to turn these signs into symbols according to the logic of an adamantine necessity, the validity of which is rigidly inculcated and repeatedly confirmed by worldly occurrence (if I have two jellybeans, and you give me one more, then I have three jellybeans). In part because of the centrality of counting for daily life and in part because of the consistency of its learned results, Wittgenstein then posits that we come to treat the logic of this technique as if it expressed what he, in his earlier work, calls a ‘mythology of the symbolism’.Footnote 16 When we are trained to use numbers as symbols that function according to absolute necessity, we learn to treat the ‘grammar’ of these symbols as if it were ‘like a string of pearls in a box’,Footnote 17 as if it were ‘something from which we … draw consequences which already exist in an ideal sense before they are drawn’.Footnote 18 We are thus formed to act as if the techniques with which we craft these symbols disclose an order of reality that metaphysically guarantees the necessity of our techniques. We treat the logic of our logic as if it names ‘a kind of ultra-physics, [a] description of the “logical structure” of the world, which we perceive through a kind of ultra-experience’.Footnote 19

The reality thereby named does not just ground the necessity of a given technique, however. It constitutes the bedrock of possibility. As Wittgenstein puts matters in his Philosophical Investigations, when we project the logic of a foundational conceptual technique into a distinct dimension of reality, we come to treat this logic as presenting ‘an order: namely, the a priori order of the world; that is, the order of possibilities, which the world and thinking must have in common’.Footnote 20 Every possibility of thought and action must then be contained in this a priori order. Whatever happens in the world can only be conceived as unfolding what logic allows – occurrence is always consequent to possibility; possibility cannot be a consequence of occurrence. Thinking according to a mythology of the symbolism thus inclines us to treat hegemonic renderings of a given symbolism as expressing the totality of what things can be and so what things most essentially are, meaning that ‘one predicates of the thing what lies in the mode of representation’.Footnote 21

We can here note two features of Brunner’s thinking that are illuminated by this reading of Wittgenstein’s reflections. First, Brunner’s logic of possibility can be read as taking on the force of necessity in the same way as mathematical symbols under Wittgenstein’s account. After all, it is a matter of fact that we typically learn to use the language of possibility on the basis that occurrence depends on prior possibility, and as with mathematics, we learn to use this language with endless practice, with merciless exactitude – a whole host of human activities depend on accurately judging what is possible under given conditions and then acting accordingly. When the logic of this language is taken as a condition of possibility for meaningful thought, we can then treat this logic as if it expresses an independent order of reality to which all our thinking must correspond, such that the meaning of ‘possibility’ becomes a matter of immutable logical reality. In Brunner’s case, the fact that he treats a principle of prior possibility as necessary for the coherence of his theology fixes it as expressing a reality with which our thinking of God must cohere.

Secondly, Brunner’s thinking of possibility inclines him to predicate of human beings what lies in his mode of representation. As an axiom, the principle of prior possibility demands that one think of an occurrence as determined by what is already possible, and so if God reveals Godself to humans, the occurrence of this revelation must likewise be grounded in what is already possible. ‘Humanity’ must therefore be thought in such a way that the possibility of revelation is grounded in the a priori order of possibilities that characterises the essence of humanity. ‘The Word of God could not reach a man who had lost his consciousness of God entirely’, and so the persistence of this consciousness must be counted among the essential predicates of humanity.

Both of these features of Brunner’s thought can be described as forms of the abstraction against which Barth inveighs across his theological corpus.Footnote 22 Brunner allows his theology to be determined by an abstract principle of human thought rather than the particularity of God’s revelation in Christ, and he forms a concept of humanity according to the logics of this abstraction. If this were the most fundamental problem with Brunner’s theology, the solution would be to avoid abstraction, whether in terms of Wittgenstein’s prescription to avoid projecting metaphysical entities from the practical logics of linguistic expression, or in terms of Barth’s prescription to begin all dogmatic thinking in Jesus Christ. There is a deeper problem in Brunner’s natural theology, however, one that is illuminated by Wittgenstein’s reflections on how the axiomatics of prior possibility constrain any effort to think beyond the auspices of their necessity.

Having traced the projection of symbolic practices into an eternal order necessity, Wittgenstein goes on to focus his full attention on the idea that we must therefore ‘only infer what really follows!’Footnote 23 In considering a particularly concentrated version of this claim, he refers to ‘what the logical machine really does produce’.Footnote 24 That is, over and above a static logical dimension, this machine is productive and putatively dynamic: it is ‘an all-pervading, ethereal mechanism’.Footnote 25 If a machine in a factory produces a helicopter part that must have already been made before a helicopter can fly, the logical machine produces the steps that must be taken in a logical argument or a mathematical series prior to anyone actually taking these steps.

Wittgenstein now argues that when we think in the manner expressed by this logical machine, we surreptitiously treat the picture of a machine as its own symbolic double. What I treat as a picture of a machine is actually a picture of ‘the machine (its structure) as symbolizing its action’.Footnote 26 It is as if I took the blueprint for a machine and held that each part of that machine could only function as the blueprint represents them. I thus relate the machine’s operation to its picture as necessarily following from this picture’s ideal reality. Because every function of the logical machine is already represented by the blueprint, to say that the machine symbolises its own action is therefore equivalent to saying that ‘the action of a machine … seems to be there in it from the start … If we know the machine, everything else, that is, its movements, seems to be already completely determined’.Footnote 27 As above, every valid step in a logical sequence can only be what the logical machine has made it to be, just as a drawer can only contain socks that I’ve already placed in it. All the thinker has to do – all they can do – is discern and follow steps that have already been determined (i.e., find and remove socks which are already there).

Among other things, Wittgenstein’s reflections draw out the fact that mythologies of symbolism involve a particular kind of reflexivity: beyond the mythological character of particular concepts, here the objects being mythologised are the means by which we form concepts writ large. The logical machine can thus be thought of as expressing a recursive principle of concept formation. Symbols woven out of relations framed by conceptual patterns must be thought as characterised by an absolute determinacy; this determinacy is then retrojected into the concepts through which symbols are bound together (the inferential principle, for example, in virtue of which the 501st figure in the series ‘2, 2, 2, 2…’ must be 2, or the conviction that revelation is only possible if the grounds of its possibility already exist in humans). We thus harden the patterns with which we think under the assumption that these patterns must always already contain all the steps that we can take. We adopt a mode of concept formation through which our concepts seem to predetermine all possible movements of meaningful thought.

The deepest significance of the logical machine for Brunner’s natural theology is now given by Wittgenstein’s reflections on what it means to think the logical machine as open to deformation. Having traced the manner in which the logical machine seems to predetermine the steps of logical thought, Wittgenstein goes on to note that when ‘we talk as if these parts [of the machine] could only move in this way, as if they could not do anything else … [we] forget the possibility of their bending, breaking off, melting, and so on’.Footnote 28 We forget that ‘a material harder and more rigid than any other’ can break,Footnote 29 even in the realm of the ultra-physical. If we do think of it as possible for the logical machine to bend and break and melt, however, something odd happens. Wittgenstein continues by writing that:

when we remember that the machine could also have moved differently, it readily seems to us as if the way it moves must be contained in the machine-as-symbol far more determinately than in the actual machine. As if it were not enough here for the movements in question to be empirically determined in advance, but they had to be really – in a mysterious sense – already present.Footnote 30

The idea of the possibility of an empirically determined malfunction is clear enough. If a car engine catches on fire, we can think of this as made possible by an oil leak, a faulty wire or a broken cooling system, each of which is, in turn, made possible by the frailty of plastic and of metal. In the case of the machine-as-symbol, however, the possibility of malfunction is not determined by empirical contingency. This possibility must be thought of as always already a constitutive aspect of the machine. In Wittgenstein’s words, ‘the movement of the machine-as-symbol is predetermined in a different sense to … any given actual machine’.Footnote 31

When we form concepts under this picture, we retroactively assimilate any possibility of their bending and breaking into our picture of the concepts thus broken. Even when what breaks is the mechanical regularity of symbolic inference, the possibility of deviation must be thought as already contained in how we conceptualise the symbolism, prior to and more determinately than how we use any given symbol. Any change in our forms of logical inference must therefore be narrated as disclosing a hitherto undiscovered operation of how we always think, not an unprecedented innovation in our fundamental forms of thought. As Wittgenstein expresses it, ‘we say, for example, that a machine has (possesses) such-and-such possibilities of movement [of bending and breaking] … What is this possibility of movement? It is not the movement, but it does not seem to be the mere physical conditions for moving either … The possibility of a movement is, rather, supposed to be a shadow of the movement itself’.Footnote 32 It is not just the case that the steps of any given logical inference are predetermined. Any possibility that these steps might be taken otherwise, and so any possibility of altering the grammars of theological thought, must be thought as pre-existing in the grounds of logical necessity, in the ‘grammar’ itself. What is ruled out is the possibility of a possibility not contained in the a priori order of the world, or an occurrence where before there was not even a shadow of its possibility.

We can now draw out the full significance of Wittgenstein’s remarks for Brunner’s natural theology. At the broadest level, in framing the necessities of his argument for natural theology according to an axiomatic principle of prior possibility, Brunner thinks according to the ‘formulation of a system which claims … to interpret divine revelation, whose subject … differs fundamentally from the revelation in Jesus Christ’, namely, a system whose subject is a principle of prior possibility. This system then limits how we can conceive ‘revelation’ in at least two ways. First, even the occurrence of the impossible in the event of revelation (a breaking of the logical machine) must rest in some pre-existent possibility. We are therefore impelled to form our concepts of the objects of revelation according to the principle that even these objects must essentially ground the possibility of that which is impossible for them. On pain of incoherence, we must cast the ‘formal imago Dei’ as a shadow of revelation. Secondly, we can only conceive revelation as a matter of disclosing what is already the case, never as the creation of a genuinely new reality. Even God can only reveal what is already there to be revealed.

Wittgenstein also illuminates, moreover, how difficult it is to escape Brunner’s logic of possibility without doing so according to that very logic. It would be easy for me to assert, for example, that my thinking begins in Jesus Christ, not a universal principle of thought, whilst also taking a principle of prior possibility as determinative for what I can think of Jesus Christ – I can sincerely hold that Jesus Christ is the sole source of revelation whilst subordinating the interpretation of this revelation to something other than the Word of God. It would be just as easy for me to denounce an explicit form of natural theology according to that form’s implicit logic, and so steadfastly deny any capacity for revelation on the creature’s part whilst rendering the event of revelation as dependent on some shadow of grace. In both cases, I think with the very thing that I am trying to think against.

More is at stake here than the question of where revelation is to be found. At stake is how one’s thinking of the world’s possibilities shapes one’s understanding not just of God’s revelation, but of God’s freedom writ large. When the logical machine breaks, we think of this as revealing a deeper reality, not a transformation of the depths; when an event takes place that seems to transcend the limits of our a priori order of possibilities, we conceive it not as something unbounded by any such order, but as revealing some hitherto unrecognised shadow. By the same token, if I conceive God according to the workings of a logical machine (even if in the breaking of such a machine), then I will think God’s possibilities as limited by an a priori order that even God cannot transform, since I will conceive any apparent transformation as the revelation of what is already the case. I thus limit my thinking of God on the basis that God cannot create possibility ex nihilo, or possibility without shadow. Even in allowing that my understanding of an a priori order of possibilities can change, I treat God’s freedom as subordinate to an order that is distinct from God’s being as the one who loves in freedom.

When read in light of Wittgenstein, Brunner’s argument for natural theology can thus be seen as fixing at the heart of his theological conceptualisation a principle according to which we can only know God as subordinated to the necessities of prior possibility. We might explicitly proclaim that God is not limited by creaturely possibilities. The logic of this language will nonetheless constrain our thinking of God according to the presupposition that even the most irruptive work of grace must have already been possible from eternity, meaning that love must be limited by shadows beyond which God cannot create. The operations of the logical machine set the limits of God’s freedom.

Barth’s ‘Nein!’ and the impossibilities of grace

I am now going to argue that in rejecting Brunner’s natural theology, Barth does indeed reject the axiomatic status of any principle of prior possibility, and through this the workings of the logical machine writ large. It need not be the case that every form of ‘natural theology’ involves treating such a principle as axiomatic. Brunner’s natural theology does – and so rejecting natural theology in toto should involve rejecting any theology that is compelled to conceive possibility as necessarily pre-contained in nature, whether that nature be human or divine. Rejecting this theology cannot, however, just involve asserting that God’s actions are not limited by any a priori order of possibilities. This rejection must also involve refusing axiomatic status to any singular conception of possibility, as well as framing the logics of our thought according to the faith that God can create possibility where before there was none, whether in heaven or on earth.

Barth’s refusal of axiomatic status to the principle of prior possibility is given most concrete form in his steadfast assertion both that creatures know God and that knowledge of God is impossible for creatures. It is axiomatic for Barth that at least some creatures know God.Footnote 33 In his rejoinder to Brunner, he nonetheless asserts that we have no ‘“capacity for revelation” which is anterior to, though it only comes alive through, revelation’.Footnote 34 In volume 2/1 of the Church Dogmatics, he writes that there is no ‘possibility of man as such [for] an openness [to] the grace of God and therefore [no] readiness for the knowability of God in His revelation’.Footnote 35 The conditions of possibility for this encounter simply do not exist in creatures. This is not, moreover, a state of affairs analogous to the fact that I cannot reach the roof of my apartment complex without a ladder, or that meat cannot cook without heat. In these examples, a given outcome is practically impossible but always possible in principle, given a change of external factors. If I am given a ladder, I can climb onto a roof; the capacity for climbing is anterior to, and ‘comes alive through’, my being given the right equipment. For Barth, creaturely knowledge of God is, by contrast, impossible in an absolute sense. No change of external factors can make it possible for humans to know God; give me all the ladders in the world, and I cannot climb to heaven. The question thus becomes, in Barth’s words, ‘how do we come to think, by means of our thinking, that which we cannot think at all by this means? How do we come to say, by means of our language, that which we cannot say at all by this means?’Footnote 36

Barth’s answer to these questions depends on the idea that God creates possibility where before there was none. As he writes against Brunner, if ‘there is an encounter and communion between God and man, then God himself must have created for it conditions which are not in the least supplied (not even “somehow,” not even “to some extent”!) by the existence of the formal factor’.Footnote 37 As he puts matters in the Dogmatics, ‘God creates in us the possibility … to know him’.Footnote 38 Indeed, this work of creation is grace, understood as ‘the orientation in which God sets up an order which did not previously exist, to the power and benefit of which man has no claim, which he has no power to set up, which he has no competence even subsequently to justify’.Footnote 39 In all, we know God not because it is already possible for us to know God, but because God makes Godself known to us despite the fact that this knowledge is impossible. God creates possibilities where before there were none.

Barth’s rejection of Brunner’s natural theology thus frames the claim that God’s activity does not presuppose possibility, even in the form of shadow. This theme in Barth’s thought then at minimum invites, at most impels a rethinking of one’s logics of possibility, on the basis that his account of revelation requires a way of conceiving possibility without pre-existence. Expressed in the form of Kathryn Tanner’s language of ‘rules for Christian discourse’, we can say that ‘Christians should not speak of God’s actions as bounded by any pre-existing order of possibilities’.Footnote 40 There are different ways of following any such rule, of course, from a deflationary Wittgensteinian approach that refuses to reify possibility as a metaphysical entity to an approach that treats possibility as some ‘thing’ that God can create. Whichever approach is taken, the important thing is that we do not conceive of God’s activity as bound by some pre-existing order of possibility. Where God does the impossible, we do not reflexively treat this impossibility as revealing some deeper possibility that already existed. In saying that God creates in us the possibility to know God, we are not therefore even saying that it was possible for creatures to receive this possibility, in the sense that we might say that it is possible for a canvas to ‘receive’ red paint. Perhaps even more disjointedly, we are not even saying that it is possible for God to reveal Godself to us. We are saying that God creates possibility in the event of revelation. We are saying that ‘God the Reconciler is the One who overcomes the disagreement which cannot be overcome, the One who heals and saves from the wound which cannot be cured’.Footnote 41

At this point, one could reasonably note that Barth does not make the argument that I am making. Indeed, he devotes §26 of the Dogmatics to articulating the possibility of revelation as grounded in God Godself, as opposed to any aspect of creation. Insofar as possibilities that exist in God can be said to pre-exist their realisation in creation, Barth can thus be read as arguing that the possibility of revelation pre-exists in God, and so as thinking according to a principle of prior possibility. The logical machine is merely internal to God’s eternity, rather than an external limit on God’s power.

I am certain that this reading of Barth is defensible, not least because Barth grounds the possibility of our knowledge of God in the eternal fact of God’s self-knowledge. It may also well be the case that Barth uses the logics of prior possibility at various points across his thought, a use that would be in keeping with his systematic lack of systematicity, his willingness to deploy whatever conceptual tools are best fitted to a particular moment of scriptural exegesis. Beyond any in-principle reason for rejecting the axiomatics of prior possibility, however, there is at least one concrete reason to read Barth’s own use of possibility apart from these axiomatics. Even as he articulates the possibility of revelation under the aspect of God’s eternity, he ultimately grounds this possibility in the fact that God has taken the impossibility of our knowing God into Godself, and in doing so created a possibility that before did not exist. As Barth writes, we know God because ‘the only begotten Son of God and therefore God Himself, who is knowable to Himself from eternity to eternity, has come in our flesh, has taken our flesh, has become the bearer of our flesh, and does not exist as God’s Son from eternity to eternity except in our flesh … In our flesh God knows himself’.Footnote 42 Crucially, however, the Son of God ‘has not entered the fellowship of the humanity defined in this way without being affected by or participating in its inner impossibility in relation to God’.Footnote 43 Expressed in the fact that the Son of God endures ‘the enmity of man against the grace of God’,Footnote 44 this inner impossibility is instead taken into the Godhead and overcome, in such a way that grace truly creates ‘an order which did not previously exist’. The incarnation does not, therefore, bring into reality a shadow contained in an a priori order of possibilities. It expresses the fact that God is not bound by any such order. Even if we then aver that it is always possible for God to create a new possibility, the possibility of God’s creation is no longer a matter of eternal shadow. It is a matter of free creation, and so a final refusal of the idea that revelation must be interpreted according to the axiomatics of prior possibility. By taking on our flesh, God explodes the logical machine.

In all, Barth’s rejection of Brunner’s natural theology means rejecting the axiomatics of prior possibility, on the basis that these axiomatics ground a system for interpreting revelation whose subject is other than Jesus Christ. Though this does not entail refusing any idea of prior possibility at all, it does mean that Christians should re-conceive the character of ‘possibility’ around the faith that God has the power to create possibility where before there was none. Whatever ‘possibility’ might mean, it must be bounded by the consistency and freedom of God’s love, not by the necessities of our practical and logical reasoning.

I am going to conclude by suggesting two implications of refusing the force of the logical machine for theological thought. The first is a constructive principle for theological reflection that can be derived by combining Wittgenstein’s account of language-learning with Barth’s theology of grace. As above, Wittgenstein argues that part of the reason why we are tempted to invent mythologies of the symbolism is the rigid inculcation of particular symbolic techniques. Even and especially as we use such techniques to construct theological arguments (after all, this paper aspires to at least a semblance of logical reasoning!), we must ensure that the practical necessity of a given form of inference is not transformed into an absolute necessity for reasoning about God.

In one respect, this means being willing, when led by our attempts to interpret Scripture, to think in ways that force a reformulation of the apparently necessary laws of thought. As Barth puts it, after all, ‘as we … form our views, concepts, and concepts according to our ability (or inability), we cannot confine ourselves to any of these words, as if we have already thought of God and spoken of God, and we have only to repeat our concepts and words to attain and express again the knowledge of God’.Footnote 45 If this is true of concepts like ‘human’ and ‘revelation’, then it is true of mathematical and logical concepts as well, perhaps even the a priori categories of thought.

In another respect, this means being willing to allow that new concepts, new possibilities of thought, can be created which are not simply the realisation of our pre-existing possibilities. If ‘the mathematician is an inventor, not a discoverer’,Footnote 46 to use Wittgenstein’s terms, the same should be true of theologians. We should thus work to form concepts according to the principle that they cannot contain all their possibilities at the moment of conception, as opposed to forming them under the presupposition that we are merely bringing shadows into existence. Without disavowing the importance of existing forms of thought (jazz musicians are typically adept at musical theory), Barth’s rejection of natural theology can thus inform a sense of theology as a mode of genuinely creative improvisation.Footnote 47

The second implication relates to the role of theology in empowering political imagination. Barth’s rejoinder to Brunner was written the same year as the Barmen Declaration, a confession that Barth describes as ‘the first confessional document in which the Evangelical Church has tackled the problem of natural theology’.Footnote 48 A great deal has been written about Barmen and its legacy.Footnote 49 Barmen has also inspired similar forms of theological resistance to tyranny, perhaps most notably the Belhar Confession against apartheid, whilst Michael Welker has recently described it as ‘a model for other church struggles in similarly dangerous situations’.Footnote 50 Allowing for the fact of Barmen’s life beyond itself, however, one of the Declaration’s less remarked upon features is that it had almost no contemporary effects. It did not blunt the march of fascism in Germany. The Confessing Church fractured almost as soon as it announced its existence. Theological confessions of the singular authority of God’s Word for the Church did not dilute the mass appeal of volkisch religion.

I do not note this inefficacy in order to critique either Barth or Barmen, as if the passage of time has illuminated a strategy that would have been more successful. Nor do I want to argue that this inefficacy is evidence that a different theological path should have been taken.Footnote 51 I am noting this inefficacy on the basis that Barmen’s rejection of natural theology, when read in light of the above, suggests a distinctive way of bringing Christian God-talk to bear on a politics of the impossible.

Toward the end of ‘Nein!’, Barth writes that:

if we base ourselves upon what is possible to us, we shall always believe in these our possibilities and always have to believe in them. Hence we shall not be able to destroy ‘the fictions of Weltanschauungen’. The power to rid ourselves of these fictions and of the illusion of our freedom which underlies them, is in no sense our power, but solely the power of the Word itself.Footnote 52

Barmen’s First Thesis confesses that ‘Jesus Christ, as he is attested for us in Holy Scripture, is the one Word of God which we have to hear and which we have to trust and obey in life and death’.Footnote 53 Its Sixth Thesis confesses that ‘the church’s commission, upon which its freedom is founded, consists in delivering the message of the free grace of God to all people in Christ’s stead, and therefore in the ministry of his own Word and work through sermon and sacrament’.Footnote 54 In light of the above, we can here note that when Christians assent to these words, they confess their obligation to do things that are absolutely impossible for them to do. We cannot know God, and yet we hear the Word of God. We cannot deliver the message of free grace, and yet this is what we are called to do. We are called to do the impossible, and in responding to this call, we base ourselves not upon what is possible to us, but on what God makes possible.

Formal theological confessions are not the kind of thing that typically shape the course of history. When understood in light of rejecting the axiomatics of prior possibility, Barmen nonetheless offers a framework for making sense of futile acts of foolish hope. Rejecting natural theology makes sense of a Christian activism that hopes for what it cannot see, not because the unseen rests on the other side of eternity, but because grace erupts at the site of its own absolute impossibility. I can only intimate such a framework here. But in refusing the axiomatics of prior possibility, in refusing the logics of natural theology any power to utterly condition one’s political will, one can find a reason to pursue acts of love that are doomed to failure. One of the devil’s greatest tools is the rational expectation that acting out of love can only end in failure. Grace can create possibility without shadow, and so we need not seek shadows of grace in order to justify acting out of faith in God’s love.

References

1 For relatively recent engagements with Barth’s critiques of ‘natural theology’, see Colin Grant, ‘Why Should Theology Be Unnatural’, Modern Theology 23/1 (2007), pp. 91–106; and Erkki Vesa Rope Kojonen, ‘Barth and the Return of Natural Theology’, Kerygma und Dogma 66/1 (2020), pp. 41–67. On Barth’s exchange with Emil Brunner in particular, see Trevor Hart, ‘A Capacity for Ambiguity? The Barth-Brunner Debate Revisited’, Tyndale Bulletin 44/2 (1993), pp. 289–305; and T. L. Smith, Natural Theology: The Dialectic of Natural Theology: Emil Brunner & Karl Barth on Nature and Grace (Saarbrücken: VDM Verlag Dr. Müller, 2010). For a comprehensive overview of Barth’s developing views of natural theology, see Keith L. Johnson, ‘Barth on Natural Theology’, in George Hunsinger and Keith L. Johnson (eds), The Wiley Blackwell Companion to Karl Barth: Barth and Dogmatics, Volume 1 (London: John Wiley & Sons, 2020). For a recent defense of natural theology, though not necessarily in the sense that Barth imagines it, see Alister McGrath, Re-Imagining Nature: The Promise of a Christian Natural Theology (London: Wiley-Blackwell, 2016); and for a critical analysis of natural theology writ large, see Andrew Moore, ‘Should Christians do Natural Theology’, Scottish Journal of Theology 63/2 (2010), pp. 127–45.

2 Johnson, ‘Barth on Natural Theology’, p. 96.

3 Karl Barth, ‘No! Answer to Emil Brunner’, in Natural Theology: Comprising ‘Nature and Grace’ by Professor Dr. Emil Brunner and the reply ‘No!’ by Dr. Karl Barth (Eugene, OR: Wipf and Stock Publishers, 2002), p. 75.

4 See especially Karl Barth, Church Dogmatics [hereafter CD] 2/1, 13 vols. (Peabody, MA: Hendrickson, 2010), pp. 172–8.

5 See Emil Brunner, ‘Nature and Grace’, in Natural Theology, pp. 15–6. For an incisive and rich analysis of Barth’s shifting and hardening views on this subject, see again Johnson, ‘Barth on Natural Theology’, pp. 98–101.

6 Brunner, ‘Nature and Grace’, p. 31.

7 Hart, ‘A Capacity for Ambiguity’, p. 294.

8 Brunner, ‘Nature and Grace’, pp. 32–33.

9 Ibid., p. 31.

10 Ibid.

11 This is so much the case that Hart does not identify it as a point on which Barth and Brunner disagree, instead arguing that Barth’s primary concern is with the possibility of properly distinguishing the ‘formal’ from the ‘material’ imago. See Hart, ‘A Capacity for Ambiguity’, p. 298.

12 Brunner, ‘Nature and Grace’, p. 32.

13 To the best of my knowledge, Wittgenstein’s reflections on mathematics have not been brought to bear directly on questions of natural theology. The closest is Philip R. Shields’ fascinating and idiosyncratic text, Logic and Sin in the Writings of Ludwig Wittgenstein (Chicago, IL: University of Chicago Press, 1992). My reading diverges from Shields’ insofar as he argues that Wittgenstein holds that our thought must ultimately cohere with the ‘hardness of the logical must’. Terrance W. Klein’s Wittgenstein and the Metaphysics of Grace (Oxford: OUP, 2007) touches on questions of grace, but not in a way that is relevant to my argument here. There have been relatively few sustained engagements with both Barth and Wittgenstein, with the most notable being Neil MacDonald, Karl Barth and the Strange New World within the Bible: Barth, Wittgenstein, and the Metadilemmas of the Enlightenment (Milton Keynes: Paternoster, 2002). I am unaware of work focussed specifically on Wittgenstein’s concept of ‘the logical machine’. For a helpful overview of his mathematical thought, see Juliet Floyd, Wittgenstein’s Philosophy of Mathematics (Cambridge: CUP, 2021).

14 Ludwig Wittgenstein, Remarks on the Foundations of Mathematics, 3rd edn (Oxford: Blackwell, 2001), p. 36.

15 Ibid., p. 37.

16 Ludwig Wittgenstein, Philosophical Remarks (Chicago, IL: The University of Chicago Press, 1975), p. 65. Wittgenstein also deploys this concept in Philosophical Grammar, where he writes that ‘in philosophy one is constantly tempted to invent a mythology of symbolism’. See Ludwig Wittgenstein, Philosophical Grammar (Berkeley, CA: University of California Press, 2005), p. 56.

17 Wittgenstein, Philosophical Grammar, p. 55.

18 Ibid.

19 Wittgenstein, Remarks, p. 40.

20 Ludwig Wittgenstein, Philosophical Investigations (Oxford: Wiley-Blackwell, 2009), §97.

21 Ibid., §104.

22 See for example Karl Barth, CD 1/1, p. 137; and 2/2, p. 660.

23 Wittgenstein, Remarks, p. 40.

24 Ibid., p. 83 (emphasis added).

25 Ibid.

26 Ibid., p. 85.

27 Ibid.

28 Ibid.

29 Ibid., p. 83.

30 Ibid., p. 85.

31 Ibid.

32 Ibid., p. 86 (emphasis added).

33 See Barth, CD 2/1, p. 64.

34 Barth, ‘No!’, p. 88.

35 Barth, CD 2/1, p.135. I have made the wording here slightly stronger than it is in the original text, but this does not distort the spirit of that original, which describes an aspect of what Barth rejects in rejecting natural theology.

36 Ibid., p. 220.

37 Barth, ‘No!’, p. 89.

38 Barth, CD 2/1, p. 33.

39 Ibid., p. 74.

40 See Kathryn Tanner, God and Creation in Christian Theology: Tyranny or Empowerment? (Minneapolis, MN: Fortress Press, 2005), p. 27.

41 Barth, CD 2/1, p. 77. I should note here that I am deliberately avoiding any distinction between ‘creatures in themselves’ and ‘creatures in relation to God’. The latter can suggest that it is possible for creatures to know God ‘in relation’ because of some quality of theirs – in the same way that a chemical element might be inert on its own but active in a compound. In Barth’s account, there is not even a latent possibility on the creature’s part which is activated ‘in relation’. This possibility is always and only created by God. So even though creatures can and do know God through revelation, it is strictly false to say that ‘it is possible for creatures to know God in relation to God’. This knowledge remains impossible in this relation; God just creates the possibility.

42 Ibid., p. 151.

43 Ibid. (emphasis added).

44 Ibid.

45 Ibid., p. 214.

46 Wittgenstein, Remarks, p. 99.

47 For a recent reading of Barth’s theology in light of jazz practices of improvisation and creativity, see Raymond Carr, Theology in the Mode of Monk: An Aesthetics of Barth and Cone on Revelation and Freedom, 3 vols. (Eugene, OR: Cascade Books, 2024).

48 Barth, CD 2/1, p. 172.

49 As well as Eberhard Busch, The Barmen Theses Then and Now (Grand Rapids, MI: William B. Eerdmans, 2010), see Hubert G. Locke (ed.), The Church Confronts the Nazis: Barmen Then and Now (Lewiston: The Edwin Mellon Press, 1984); and Fred Dallmayr, The Legacy of the Barmen Declaration: Politics and the Kingdom (New York, NY: Lexington Books, 2019).

50 Michael Welker, ‘The Significance of the Theological Declaration of Barmen 1943 and “Christophobia in Europe” Today’, Theology Today, 81/3 (2024), p. 84.

51 The Barmen Declaration should have directly refuted antisemitism, and it is likely that this refutation would have required Barth (for all his undoubted courage in this regard) to rethink his own understanding of Judaism. Questions can also be raised regarding Barmen’s implications for non-Christians, as well as its limited focus on Christian autonomy rather than the wider evils of political tyranny. But the fact that Barmen could have been made better does not mean that Barmen could have been made more effective. Theological declarations tend not to directly shape the course of history, whatever the content of their claims; the power of Christian God-talk does not rest in the force of formal pronouncements. For critical analyses of Barth’s understandings of Judaism, as well as the relationship of Barmen to Judaism in particular, see Katherine Sonderegger, That Jesus Christ was Born a Jew (University Park, PA: Penn State Press, 1992); George Hunsinger (ed.), Karl Barth, the Jews, and Judaism (Grand Rapids, MI: Eerdmans, 2018); Mark Lindsay, Barth, Israel, and Jesus: Karl Barth’s Theology of Israel (London: Routledge, 2016); and Victoria J. Barnett, ‘Barmen, the Ecumenical Movement, and the Jews’, The Ecumenical Review 61/1 (2009), pp. 17–23.

52 Barth, ‘No!’, p. 117.

53 ‘The Theological Declaration of Barmen’ §8.11, in Arthur C. Cochrane, The Church’s Confessions Under Hitler (Philadelphia, PA: Westminster Press, 1962), pp. 238–42.

54 Ibid., §8.26.