1. Introduction
As Karin de Boer notes, Moses Mendelssohn famously referred in his Morning Hours to ‘the all-quashing Kant’ (Mendelssohn Reference Mendelssohn2011: p. xix). Less well-known is Mendelssohn’s reference, a few paragraphs later, to ‘the profundity of a Kant who will hopefully build up again with the same spirit with which he has torn down’ (p. xx). De Boer’s book, Kant’s Reform of Metaphysics (De Boer Reference De Boer2020; references throughout simply by page number), is a tremendous advance in Kant scholarship, giving the best account so far of the reform of Wolffian metaphysics that Kant promised and for which Mendelssohn hoped.
The interpretation of Kant as fundamentally anti- or post-metaphysical has taken more than one form. In the context of what came to be called neo-Kantianism, it seemed essential to distinguish Kant’s critical philosophy both from the speculative metaphysics of absolute idealism and from materialism. One influential way to accomplish this was to focus on Kant’s account of the necessary conditions for the possibility of science to the exclusion of his metaphysical project, as Hermann Cohen did (see Cohen’s seminal work, first published in 1871 then revised several times, Kants Theorie der Erfahrung; in Cohen Reference Cohen, Holzhey and Weidebach1987). A few decades later, in the context of logical empiricism and ordinary language philosophy, it seemed essential to read Kant as the formulator of a principle of significance that anticipated the verification principle of meaning, but also as articulating a richer conception of experience than was associated not only with Hume but with logical empiricism itself. Accordingly, Sir Peter Strawson’s Kant focused on the necessary conditions of the possibility of ordinary – not scientific – experience (Strawson Reference Strawson1966). Both Cohen and Strawson, in their different ways, presented Kant’s philosophy as discontinuous with the metaphysical tradition in which he had been educated and to which he had dedicated the first – so-called ‘pre-critical’ – part of his career.
De Boer is not the first to push back against the anti- or post-metaphysical interpretation of Kant’s critical project. Notably, Heidegger did just that (see Heidegger Reference Heidegger1997, and the illuminating discussion in De Boer and Howard Reference De Boer and Howard2019). But he did so within the context of his own understanding of metaphysics in terms of the question of the meaning of being, and in the context, in particular, of his contestation of Cohen’s conception of the history of philosophy since Plato, the Jewish contribution to which Cohen made explicit in his late work. In contrast, De Boer situates Kant’s project firmly within a carefully reconstructed account of Wolff’s metaphysics, its development by Baumgarten and its criticism by Crusius – in short, within Kant’s own context.
Today, metaphysics is very far both from having the bad reputation that it had during the heydays of neo-Kantianism and logical empiricism, and from having the meaning given to it by Heidegger. Nevertheless, it has remained a desideratum of Kant interpretation to clarify Kant’s positive intentions with respect to metaphysics, which requires a clarification of the nature of the metaphysics of Wolff and his school, as well as of Kant’s relationship to metaphysics in the Wolffian sense. Successfully carried out, such an endeavour sheds light not only on the whole of Kant’s project, but also illuminates numerous obscure passages, and does so without losing sight of Kant’s concern with the necessary conditions for the possibility of experience, which Kant in fact understood as at once both ordinary and scientific, since there was for him no rupture between the two. On the well-supported and lucidly argued view developed by De Boer, Kant did not regard his account of the necessary conditions for the possibility of experience as an end in itself, but rather as a means whereby he could make explicit the conditions under which metaphysics could at last be set on the sure path of a science.
Yet questions remain, as I will try to show. Most glaringly, why did Kant fail to carry out his projected reform of Wolffian metaphysics? Could this aspect of his project have been overshadowed or even overwhelmed by the more radical thrust of his developing thoughts?
2. Revolution and standpoint
As De Boer documents in meticulous detail, Kant was committed to the reform of Wolffian metaphysics, and he gave numerous suggestions and hints, both in notes and correspondence and in the Critique of Pure Reason, as to how this reform could be carried out on the basis of his critique of the human faculty of cognition.
But, as De Boer also acknowledges, Kant also hoped to prepare the way for a revolution whereby metaphysics would become a science (p. 49). There is no contradiction here. But there are important questions of emphasis. How did the revolutionary change and the reformist project interact within Kant’s thinking?
In a well-known passage from the Preface to the B edition, Kant compares the change that he hopes to enable in philosophy with the ‘revolution brought about all at once’ that set mathematics and natural science on the sure path of science (CPR, Bxvi; translations throughout from Kant Reference Kant1998). He proceeds to compare his own ‘experiment’ to ‘the first thoughts of Copernicus’ (ibid.). However, in focusing on the turn from geocentrism to heliocentrism and on his own reconceptualization of the truth of metaphysical cognition, Kant leaves himself open to Bertrand Russell’s charge that ‘Kant spoke of himself as having effected a “Copernican revolution”, but he would have been more accurate if he had spoken of a “Ptolemaic counter-revolution”, since he put Man back at the centre from which Copernicus had dethroned him’ (Russell Reference Russell1948: p. xi).
In fact, Russell misses the core of the analogy, which is the concept of relativity-to-perspective or, to use Kant’s preferred term, the concept of standpoint. By attending to what Russell misses, we can get clear about the essence of Kant’s revolutionary ambition, and we can secure a position from which to assess De Boer’s interpretation of Kant’s relation to metaphysics.
It is a consequence of the Copernican turn from geocentrism to heliocentrism that everyday perceptions of celestial motions need to be relativized to the human standpoint on a moving planet, and it is a consequence of Kant’s reconceptualization of truth that presuppositions concerning metaphysics need to be considered in relation to the standpoint of human beings as finite, rational beings with contingent forms of sensibility. As we can speak of the sun rising and setting only from our standpoint on earth, ‘We can accordingly speak of space, extended beings, and so on, only from the human standpoint’ (A26/B42). Although Kant does not spell everything out explicitly, it is possible to trace his rethinking of other fundamental concepts, beyond the Transcendental Aesthetic, in accordance with this fundamental move. Less often discussed than his comment about the forms of sensibility is Kant’s observation that ‘One can regard every concept as a point, which, as the standpoint of an observer, has its horizon, i.e., a multiplicity of things that can be represented and surveyed, as it were, from it’ (A658/B686). If this is the case with concepts in general, then the transcendental unity of apperception, which provides the form of both concepts and judgements, each of which may be considered both as analytic and as synthetic unities, should be rethought as the form of the perspective of a finite rational being in general.
There is much more to be said about all this, of course, but it is clear enough that Kant thought that, insofar as both dogmatists and sceptics are transcendental realists who have not taken the Kantian analogue of the Copernican turn, they lack the concept of the human standpoint and have not rethought their basic terms in its wake. In other words, they are transcendental realists, but they cannot see themselves in this way because they lack the resources with which to draw an adequate version of the transcendental/empirical distinction. It is in this light that the question of Kant’s proposed reform of metaphysics should be seen. How far does the transcendental idealist revolution centring on the concept of perspective call for such a reform, and how far does it call for a comprehensive rethinking of the metaphysical tradition?
Moreover, it is arguable that Kant made two further moves after the first Critique that deserve to be called revolutionary: the articulation of the primacy of the practical in the Critique of Practical Reason, and the explication of a new conception of systematicity in terms of reflecting judgement and its principle in the Critique of the Power of Judgement. These new developments occurred in the second and third critiques in response to problems that were not even formulated at the time of Kant’s composition of the first critique: the need for a deduction of the principle of practical cognition of the good, and the need for a deduction of the principle of judgement understood as concept application.
To be clear, none of this means, in my view, either that Kant’s thinking became ‘post-critical’, or that Kant had to abandon the idea of a reformed metaphysics involving a comprehensive account of the predicables of pure understanding and reason, along with all their derivatives. But to what extent would the organization of such a metaphysics have continued to resemble Wolff’s in both structure and content, had Kant carried out the task after the second and third critiques? Supposing the organization were to remain similar, would the importance of the similarity have been eclipsed by the significance of Kant’s rethinking of all the terms involved?
3. The table of categories
One of Kant’s criticisms of metaphysics – a criticism that may predate the turn that gave rise to the critical philosophy – is that it is insufficiently systematic. Kant hoped to remedy this lack of systematicity by means of the table of categories, as De Boer notes: ‘According to various passages from the Critique of Pure Reason, Kant thought he could remedy the perceived lack of systematicity of Wolffian metaphysics by means of the table of categories’ (p. 223). Indeed, citing Kant’s Prolegomena, De Boer points out that ‘Kant held that all branches of metaphysics [and not only ontology] ought to be elaborated by using the table of categories as a guiding thread’ (p. 231, referring to Prol., §39, 4: 325). She gives an illuminating account of how Kant developed this thought within rational physics, rational psychology and rational cosmology. But she also observes that, in rational theology, ‘By and large, Kant’s exposition follows Baumgarten’s, which is to say that he does not treat the transcendental predicates of God according to the table of categories’ (p. 245).
What accounts for this variation? Is it merely that Kant ran out of steam when writing this part of the Critique, and recycled some of his older material? Or is there a deeper reason? Related questions arise in both the second and third critiques. In the Critique of Practical Reason, the table of categories of freedom diverges of course from the familiar table, but Kant barely discusses it and its significance is far from clear (see Kant Reference Kant2015; 5: 66). In the Critique of the Power of Judgement, Kant puts the category of quality before the category of quantity, an apparently minor but highly consequential divergence (Kant Reference Kant2000; 5: 203).
The only way to assess these variations in Kant’s deployment of the table of categories, I would argue, is to consider the table of categories in relation to its underlying principle and to Kant’s conception of judgement, with special attention to the explicit transformation of the latter conception in section 19 of the B version of the Transcendental Deduction. What does judgement mean in all these cases, and can context-dependent variation in the conception of judgement explain variation in the articulation and order of the categories? I have argued elsewhere that there is an intimate relation between the Transcendental Ideal, which lies at the heart of Kant’s critique of rational theology, and the Metaphysical Deduction in which he derives the table of categories (see Franks Reference Franks2005: 70–8). It is also arguable that Kant’s successors explored this intimate relationship when they developed their own speculative logics, starting from divine determinations and proceeding to derive categories by dialectic and delimitation. De Boer focuses in large part on Kant’s own declarations that what remained incomplete was not the development of the categories on the basis of their principle, but rather the derivation from the categories of pure predicables. Is it possible, however, that Kant’s own variations – not to mention the logical contributions of his successors – showed that his work on the table of categories itself and its derivation remained unfinished? By ‘unfinished’ I mean not merely that there were foreseeable steps that Kant had not yet taken, but that the principle of the table and the categories themselves, along with the very notion of judgement and concept, may have undergone change as Kant explored, at the heart of metaphysics, the implications of his revolutionary transformation of the concept of judgement.
4. Metaphysical theses
It emerges from De Boer’s discussion that the main aspect of Wolff’s general metaphysics that Kant wanted to reform was the project of formulating a rigorous and comprehensive system of concepts required for the thought and cognition of anything whatsoever. It is not quite so clear what room there would be in Kant’s reformed version of metaphysics for judgements about beings in general. Kant argues that we cannot make cognitively significant judgements about supersensible beings, but can we nevertheless make judgements about the supersensible grounds of sensible appearance? Even if such judgements are not cognitively significant, can they still be rationally permissible or even rationally necessary?
For example, De Boer writes that ‘The passages in the Critique of Pure Reason that seem to refer to the merely intelligible cause of matter only make sense, it seems to me, if we assume – with Rae Langton – that Kant in this work does not reject Leibniz’s monadology and his own early sketch of a physical monadology in all respects’ (p. 123). On this view, ‘outer appearances are grounded in a monad-like something’, and ‘Kant continued to accept a minimal and agnostic version of Leibniz’s monadology’ (p. 124). This seems to be a plausible reading of passages such as B66–8, as well as related passages in the Metaphysical Foundations of Natural Science. It would follow that one may or even should rationally judge that the properties of beings in general are ultimately grounded in the intrinsic properties of something = X. Are there other warranted judgements about beings in general in Kant’s reformed metaphysics?
So far, I have raised a question about theses in general metaphysics. But what of special metaphysics? Kant himself seems to answer in the negative: ‘There is … no canon for [reason’s] speculative use at all (for this is through and through dialectical); rather all transcendental logic is in this respect nothing but a discipline’ (A796/B824). But is it clear why this should be so, once minimal and otherwise agnostic theses are seen to be admissible or even required in general metaphysics? Here too, I would single out Kant’s rational theology for special attention. The dialectical illusion at the heart of the transcendental ideal may preclude demonstrative proof of God’s existence, and may cohere with a merely regulative use of the ideal within theoretical cognition. But is the claim that we cannot cognize God as an object compatible with the warranted judgement that there is something = X that underwrites that systematicity of reality at which we aim in our ever incomplete attempts to systematize our theoretical cognition? Of course, Kant argues that there is practical-rational warrant for faith in God as the guarantor of the highest good, but could there not also be – on De Boer’s interpretation – minimal and agnostic theoretical-rational warrant for faith in something = X as the guarantor of theoretical intelligibility?
5. Concluding questions
In closing, I return to my main question, which I hope to have given further depth and force by the intervening discussion. Why did the project of reforming and completing the system of metaphysics lose ‘much of its appeal’ for Kant, as Karin de Boer acknowledges it did? Just as importantly, what appeal, if any, did this project retain? Would the fulfilment of this endeavour not have required significant reorganization, not only in light of Kant’s critical investigation of the necessary conditions for the possibility of theoretical object-cognition, but also of subsequent developments such as the turn to the primacy of the practical in the Critique of Practical Reason, and the turn to reflective judgement and its principle as a path towards systematization in the Critique of the Power of Judgement? What room would there have been in the never completed system of reformed metaphysics – general and special – for doctrinal rather than merely disciplinary judgements? And, finally, is it not appropriate to say that, although Kant did indeed set out to reform metaphysics – as De Boer shows in the most convincing and illuminating way – he nevertheless, perhaps in spite of his initial intentions, initiated a revolution?
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