Maimon on the (In-)dispensability of the Kantian Thing in Itself: A Misleading Narrative

1. Kantian Idealism and Its Early Reception: Some Preliminaries

Kant’s doctrine of appearances and things in themselves raises a host of questions. Questions related to our purposes concern both the meaning of terms like ‘thing in itself’ and ‘appearance’ (e.g., What kind of entity does the concept of a thing in itself describe?), as well as the status of the entities (e.g., Do things in themselves exist? Should they?).

It is relatively uncontroversial that the Kantian term ‘thing in itself’ or ‘things in themselves’ is co-extensive with the expression ‘mind-independent world’ or ‘mind-independent entities’: it makes sense to use this term (in German: ‘Ding an sich’) to refer to an entity (‘thing’) independent of its relation to other things, including minds (‘in itself’).⁶ But this leaves many questions open. One such question, which dominated early discussions of Kantian idealism and to which we first turn, concerns Kant’s commitment to the existence and role of such mind-independent entities.

In a number of places, Kant appears committed to things in themselves that affect us, that is, have a (causal) impact on us (AA 8: 215, A190/B235) and serve as the ground of appearances (AA 4: 314–15, AA 4: 451, A379–80, A494/B522).⁷ Such commitment is arguably at play in the very first pages of the main part of the Critique, the Transcendental Aesthetic, where Kant starts building his entire account by speaking of an object that (causally) affects us, thereby supplying us with sensations. These sensations constitute the ‘matter’ of experience, its a posteriori aspect (as opposed to its a priori one, the ‘form’ of experience, which precedes experience—in a justificatory, albeit not temporal sense). It is in this way that objects are given to us (A19–20/B33–4).

For early readers like Jacobi (1787) and Schulze (1792: 182/[260], 184/[263–64]), the object that affects us and is thus given to us, being responsible for the a posteriori aspect of experience, has to be a mind-independent object, a Kantian thing in itself.⁸ More broadly, Schulze (1801b: 221) advocated the realist thought that this commitment is crucial if one wants to uphold the Kantian distinction between appearance (Erscheinung) and illusion (Schein). Relatedly, he thought that a relation to objects as existing independently of us, i.e., as things in themselves, belongs to the ‘essence of truth’ (Schulze 1792: 160/[225] n.). Similarly, in Jacobi’s (1787: 109) view, any adequate conception of the power of sensibility should imply ‘a distinct real medium between what is real and what is real,’ i.e., between epistemic agents and the mind-independent world.

It is views like these that proponents of the historically dominant reading of Maimon have in mind when they associate Kant’s contemporaries (up to and including Schulze) with realism (Atlas 1964: 23–4), while contrasting this with Maimon’s approach (Bondeli 2014a: 1149; cf. Bondeli 2014b: 1182). Schulze’s realist conception of truth, in particular, is taken to be criticized by Maimon on precisely such grounds (Engstler 1998: 161 n. 2 and 170); in the historically dominant view, Maimon disentangles the ‘standards’ or ‘measure’ of truth and knowledge from any reference to the mind-independent world (Beiser 1987: 292, 306; cf. 283–84, Grundmann 1998: 134, 139).

In the next sections, I expand on some aspects of the historically dominant reading—which are crucial to understanding the overall dispensability thesis attributed to Maimon—and why we should resist it. Before doing so, however, let us turn to two important, and potentially confusing, questions regarding the use of the terms ‘realism’ and ‘antirealism’ in relation to Kant’s idealism and its early reception: while such terminology has been employed in existing scholarship on German philosophy—and its employment on my part thus helps make the contrast to existing accounts clearer—we also need to flag some potential complications that emerge from its use in a (post-)Kantian context and merit some clarificatory remarks upfront.

One source of potential complications turns on the famous Kantian distinction between transcendental realism and transcendental idealism: even if one agrees on the indispensable role of the thing in itself in a Kantian framework, one could still think that this would not make Kant a realist; Kant is a transcendental idealist who explicitly rejects transcendental realism (A369)—as everyone, including readers who attribute to Kant a commitment to things in themselves, would readily admit.

In the face of this complication, it is important to keep in mind the Kantian distinction between material and formal idealism (AA 4: 375, 11: 395), as well as the somewhat related distinction in contemporary philosophy between global and local antirealism. As I see it, differing positions on the thing in itself amount to differing positions on questions of (anti-)realism as a global position, i.e., as a position on the status and role of the mind-independent world as such. Being a realist as regards this global dimension is compatible with an antirealist take with respect to local dimensions: for example, with respect to debates on space and time. (And this local dimension is indeed the original context of the distinction between transcendental idealism and transcendental realism, defined by Kant as doctrines about space and time.) One could think, for example, that spatiotemporal features of objects are mind-dependent, embracing thus Kantian formal idealism, while still rejecting a stronger, global form of antirealism—which we could perhaps term, in Kantian parlance, ‘material idealism’.

In this essay, in employing the ‘(anti-)realism’ terminology, I am always referring to debates around realism as global positions, while not wishing to deny that two (global) realists can have diverging local views (for example, with respect to time and space). For our purposes here, questions about such local debates, along with the terminological complications that their discussion would introduce, can be set aside.

A further source of potential complications has to do with some (vigorous) debates in Kant scholarship that go under the label ‘one- vs two-world interpretations of Kant’s idealism’, and could be thought to have an impact on debates around realism in a (post-)Kantian context. This issue is connected with the question of the meaning of the Kantian term ‘appearance.’ While it is relatively clear that ‘appearance’ refers to entities that are somehow mind-dependent, it is less clear how we should understand the exact notion of mind-dependence implied by the concept of a Kantian appearance and, relatedly, the relationship between appearances and things in themselves. In one kind of interpretation, appearances are mind-immanent and are to be contrasted with mind-transcendent, external-world objects (things in themselves). In this picture, the distinction between appearances and things in themselves amounts to a distinction between numerically distinct entities, two ‘worlds’. (The most recent, elaborate two-world interpretation is developed in Jauernig 2021.) Interpreting Kantian idealism in this way is highly controversial, though, and it has come under attack by readers who argue for a one-world interpretation. In the alternative reading, appearances are not to be ‘mentalized’; they are external-world objects that are numerically identical to things as they are in themselves. (Such interpretations are developed, for example, in Allison 2004, Langton 1998, and Allais 2015.)

This could sound like a highly relevant debate when it comes to understanding issues revolving around (anti-)realism in the early reception of Kant. For one thing, Maimon scholarship sometimes uses the ‘identity’ vs. ‘distinctness’ terminology in attempts to capture the difference between Maimon and Schulze (Bergman 1967: 18). Moreover, in broader discussions of the early reception of Kant, we find the assessment that (at least) some early critics presupposed a two-world interpretation of Kant’s doctrine (Sassen 1997: 438 n. 63).

Taking our cue from these hints in the literature, we could perhaps try to reconstruct the reasoning in defense of the relevance of this newer debate as follows. As regards Jacobi and Schulze, it is clear that they assume a reading of Kant that we would nowadays classify as a two-world reading: Jacobi (1787: 105) and Schulze (1801a: 379) take Kantian appearances to be ‘representations’ or ‘perceptions’, that is, some sort of mental state. Now, if one were to think that Maimon, in contrast to Schulze and Jacobi, does not endorse a two-world reading of Kant’s idealism, then this could be thought to have important consequences for how we frame issues of (global) (anti-)realism and for the role of the thing in itself within such debates. What if Maimon has an understanding of appearances as sufficiently robust, extramental entities, so that one could do justice to the realist features of Kant’s position, while in a sense dispensing with things in themselves? In this case, questions of (anti-)realism on the one hand, and of the (in-)dispensability of the thing in itself on the other hand, would perhaps come apart.

This is a line of thought that I do not pursue here, and want to urge resistance against. First, while it is true that some early versions of one-world readings in Kant scholarship have proposed the idea of ‘realism without the thing in itself’ (Bird 1962: 18–35, Prauss 1974: 192–227),⁹ it is also true that most one-world readings, including the most prominent ones, do not accept this idea. (See, for instance, Allison 2004: 64–8, Langton 1998: 7–14, Allais 2015: 27–36, 65–70.) Second, I see no evidence that Maimon adopts a one-world reading and, in fact, as I will (tangentially) remark in the next section,¹⁰ I see evidence for the opposite view. In the next sections, I set the one- vs. two-world debate aside: despite its prima facie relevance, it turns on subtle questions in Kant scholarship that ultimately do not matter for our purposes here, while having the potential to obscure things that do matter. This is fully compatible with the idea that early episodes in German philosophy can (sometimes) be fruitfully connected to newer debates in Kant scholarship.¹¹

With these clarifications in place, I now proceed to discuss questions of (anti-)realism and the (in-)dispensability of the thing in itself, bringing the two close to each other and placing Maimon’s views and texts center stage.

2. The Thing in Itself in the Essay: Realist Standards Not Fulfilled, and the Project of Consistent Skepticism

Maimon’s proclamations on the thing in itself can be found in many places. In this and the next section, I single out two of the, to my mind, most influential and challenging types of passage—in the Essay and the Logic, respectively—which have often been cited as major textual evidence for the historically dominant reading. In both cases, I cite (portions of) the relevant passages and present their antirealist reading, which has been commonly thought of as natural and obvious, not needing any elaborate argumentation in its support. I then proceed to argue, in a more painstaking way, why we should abandon the prima facie natural reading. Some of the strategies I develop are applicable to further passages not extensively discussed here, and I hint at this on occasion.

In the Essay, Maimon presents a series of reflections on the issue of affection, which, as we saw above, concerns the source of the ‘matter’, the a posteriori aspect of experience. Whereas readers like Jacobi and Schulze linked the ‘affecting object’ to the Kantian thing in itself, Maimon seems to disagree. He stresses the need to disentangle the question of affection (along with related questions with respect to the ‘given’ and the distinction between a priori and a posteriori) from the question of the thing in itself. In response to the question of what it means for an object to be given to us, or to affect us, he writes in the Essay:

Kant very often uses the word ‘given’ in connection with the matter of intuition; by this he does not mean (and nor do I) something within us that has a cause outside us. (GW 2: 203)¹²

This point is reiterated in his Logic, where he similarly writes:

That the faculty of cognition is affected means that it obtains cognitions which are not determined by its laws a priori. The things in themselves thus do not play a part at all here. (GW 5: 435/[377])¹³

Some further remarks in the Essay point in a similar direction. In a discussion of idealism, dualism, and materialism, Maimon distances himself from all these positions—as commonly understood—because they all seem compelled ‘to relate the modifications of their consciousness to something outside it’ (GW 2: 161); Maimon thinks instead that ‘the representation of an object as the objective substrate is [to be] rejected’ (GW 2: 162).¹⁴ (This reading could be thought to be reinforced by a further remark (GW 2: 202), to which we will return.)

Such remarks are commonly read as a declaration of the dispensability of the thing in itself. Now, it is important to get clear on what a dispensability thesis amounts to exactly: as we will see, although such a thesis includes a call for an elimination of the Kantian thing in itself, it is not exhausted by it. I start by exploring a distinction between dispensability (proper) and (mere) eliminability, as it is crucial for understanding both the standard reading of the passages as well as, in a second step, the proposed alternative.

Taken in itself, a call for an elimination of things in themselves could be characterized as a ‘mere eliminability thesis’ with respect to things in themselves.

Mere eliminability: A commitment to the mind-independent world is not justified. We cannot, starting from a certain explanandum such as the phenomenon of affection, infer the existence of mind-independent objects. We should therefore discard mind-independent objects as existing posits in our ontology.

Whereas existing readings clearly attribute to Maimon an eliminability thesis, often in the course of spelling out Maimon’s distinctive take on the thing in itself,¹⁵ it is equally clear that, in the historically dominant reading of these and related passages, Maimon also goes beyond a mere eliminability thesis: he is taken to endorse a further set of claims, which, in conjunction with mere eliminability, amount to a genuine dispensability thesis (and a related, genuine antirealist thesis) that I wish to call ‘dispensability proper’.

Dispensability proper: In discarding the mind-independent world, we do not simply ban it as an existing posit in our ontology. We ban it as a standard/measure of truth (or objectivity) for any of our claims, and show it to be irrelevant, in the sense that we can adequately explain all that needs to be explained without invoking it. The new, immanent to consciousness, explanans performs in a satisfactory way the functions previously assigned to the mind-independent world.

The distinction between mere eliminability and dispensability proper is connected to questions of realism. Someone who endorses a commitment to the mind-independent world (as part of their ontology) is an ‘optimistic realist’, and surely differs from someone who, by contrast, upholds the eliminability thesis. However, the latter could still be a ‘pessimistic, disappointed realist’: while denying that a certain commitment is justified, thus endorsing skepticism, the disappointed realist could still think that the entity at stake is the ‘standard of truth’ against which our beliefs are measured—and found wanting. This contrasts with an antiskeptical position, which would strive to secure the epistemic accessibility of reality by upholding the adequacy of an antirealist conception thereof.

The standard narrative on Maimon takes him to be calling for the elimination of the Kantian thing in itself in a rather distinctive sense, along the lines of dispensability proper. In that view, we could have an adequate, fully satisfactory account of the affection phenomenon, or of the distinction between a priori and a posteriori, without any appeal to a mind-independent world. Such a picture is suggested by formulations in the literature that run along the following lines: Maimon’s overall project is read as one which eliminates the thing in itself while retaining its functions (Bergman 1967: 13–4). Entities immanent to consciousness take over its functions, and perform them in a satisfactory way (Cassirer 1920: 80–1), thus rendering the thing in itself redundant/unnecessary (Atlas 1964: 44). The alternative account explains all that needs to be explained while avoiding the difficulties of the contender, thus being superior (Frank 1997: 126). The thing in itself is shown to be irrelevant, and this is coupled with the idea that, unlike accounts that invoke the mind-independent world, the alternative gives an intelligible explanation of the phenomena we are interested in (Hoyos 2008: 238, 269). Such formulations, in addition to the ones turning explicitly on issues of realism and standards of truth and knowledge—cited in the previous section—show that Maimon’s views are commonly taken to imply dispensability proper.

I now proceed to present and argue for an alternative reading of Maimon’s Essay remarks. I do not dispute that Maimon calls for an elimination of things in themselves; I agree that he supports mere eliminability. However, this does not mean that Maimon’s ‘immanent’ account of affection is presented as a fully satisfactory account, on a par with the one it is meant to rectify—Maimon does not endorse dispensability proper. Below, I will first articulate philosophically the type of view I have in mind, connecting philosophical questions with some historical reflections on some nuances of the early reception of Kant more broadly. I will then point to textual grounds that support attributing to Maimon this type of view.

Philosophically speaking, a dispensability-proper thesis is not entailed by Maimon’s remarks. An alternative, weaker conception of a certain phenomenon (affection without appeal to a mind-independent world) can have the advantage of being easier to justify than a more demanding conception (affection with appeal to a mind-independent world), or the advantage of not introducing any inconsistencies (as the more demanding conception perhaps does). This is, however, compatible with the weaker conception being introduced as an impoverished conception, not meant to perform the functions of the richer conception. One could introduce such a weaker conception and still think that the stronger conception is superior in the following sense: only the latter would be compatible with a non-skeptical view of the world and of our cognitive situation; i.e., a view that would uphold the reality of the phenomenon of affection in a way that would, for example, exclude skeptical, brain-in-a-vat scenarios. If one were to uphold such a non-skeptical view of the phenomenon we are interested in, then the mind-independent world would have to feature in any adequate account of that phenomenon. In such a view, we would count as realists (for accepting core realist intuitions about what an adequate, non-skeptical account of reality and our cognitive situation has to deliver), but we would specifically be disappointed realists, since we would think that such core realist intuitions can only be done justice to on pain of contradiction, or through the introduction of unjustified assumptions. All we are legitimately left with is an impoverished conception.

What would the motivation be for this kind of view? Why would one accept that a stronger conception of a certain phenomenon is in a sense superior, while also trying to provide a weaker, impoverished conception? Such a package of views could be appealing to a thoroughgoing, consistent skeptic for two main reasons. The first would be the exegetical ambition to (re-)interpret Kantianism in a way that purges it of inconsistencies and unjustified assumptions. Given that Kant does use certain expressions (‘affect’, ‘given’), the project could be to give such expressions a gloss that is compatible with skepticism, so that we get consistent skepticism. A related, but more philosophical motivation for this set of views would be that of defending skepticism (not any version of antirealism) against more optimistic positions with respect to our epistemic access to reality. The distinction between affecting object and affected subject, or between a priori and a posteriori, could present itself as an intuitive distinction that could namely mislead us to think that we are justified in assuming the existence of a mind-independent world. Against this type of optimistic reasoning, the skeptic would try to show how these distinctions are compatible with, and can even be drawn from the perspective of a consistently pessimistic skepticism.¹⁶

The view I suggest bears certain similarities to some positions standardly—and correctly—classified as operating within a realist framework, despite their having nuances that complicate the overall picture: the positions of Jacobi and Schulze. For instance, Jacobi (1787: 112) urges the transcendental idealist to ‘have the courage to assert the strongest idealism that has ever been taught, and not even to fear the charge of speculative egoism.’ Such statements—presumably for reasons similar to Maimon’s case—have sometimes created confusion as to where exactly Jacobi stands. But, it is ultimately clear that Jacobi’s point is not that the thing in itself is dispensable in the sense of dispensability proper.¹⁷ Maimon could be read as following Jacobi’s advice when presenting a purged account of Kantian idealism, so that no illegitimate assumptions about the thing in itself are involved. However, as in the case of Jacobi, the call for elimination need not imply the adequacy of the purged account: there would be significant losses, and the resulting picture would be skepticism.

Similarly, Schulze is happy to concede that we can provide an account of affection that would not appeal to mind-independent objects, if what we mean by this is an alternative explanation such as an evil-demon scenario.¹⁸ Schulze, advocating external-world skepticism in Aenesidemus, is happy to accept mere eliminability. This position also forms the background of a complaint against Karl Leonhard Reinhold. In Schulze’s reading, Reinhold argues, via an inference to the best explanation, for the existence of things in themselves, starting from the fact that something is ‘given’; Schulze (1792: 203/[293–94]) thinks that this is a bad argument. Maimon’s rationale against attempts to link the ‘given’ too closely with the thing in itself can be the rationale of a skeptic who protests optimistic positions à la Reinhold, and who severs the link between the ‘given’ and the thing in itself in order to guard us against such attempts. As in the case of Schulze, we can still have realism at play here. Maimon’s realism, like Schulze’s, would not consist in accepting the existence of a mind-independent world—realism should not be understood as a first-order metaphysical claim as to whether certain types of (mind-independent) entities, namely things in themselves, exist. Rather, realism could be construed as a meta-metaphysical claim about the standards of debates on reality: namely, whether an ultimately satisfactory, non-skeptical account in such debates should make reference to a mind-independent world.

This is crucial for understanding the suggested indispensability of the thing in itself and how it differs from more straightforward cases, thus giving rise to the (misleading) impression of its redundance. In straightforward cases of optimistic realism, such as in the context of indispensability arguments in contemporary philosophy of science or mathematics, the indispensability of certain (unobservable) entities (whose status is controversial) would consist in the claim, via an inference to the best explanation, that we are allowed to include them as existing posits in our ontology, on the basis of their indispensable explanatory role (in our best scientific theories).¹⁹ In these contexts, skepticism about the explanandum (the truth of our best scientific theories), and/or the possibility of providing an adequate explanation for it, is standardly not taken seriously.

This notion of indispensability differs from the one we find in Maimon (or Schulze). In the suggested view, the thing in itself is necessary by serving as an indispensable explanatory ground in an adequate explanation that would provide us with a non-skeptical picture of reality and of our cognitive situation. However, in contrast to contemporary indispensability arguments, and in line with skeptical concerns, early Kant readers take seriously the idea that the truth of the explanandum (the phenomenon of affection in a demanding, i.e., incompatible with skepticism, sense) can be called into question, and that an adequate, satisfactory explanation might not be available.

The view I am suggesting is not only conceptually possible, or suggested by historical reflections on the nuances of the early reception of Kant; there is also a textual basis for it. In addition to some direct yet marginal evidence, to which I call attention in Section 4, we find some indirect hints in the Essay and further major works. In almost all the places where Maimon introduces his weaker conception of ‘affection’ and the ‘given’, he motivates this by merely appealing to its comparative legitimacy (namely the fact that, unlike the stronger conception, it is not faced with justification and inconsistency problems), and not, for example, by appealing to its comparable explanatory power—which could thus render the stronger conception redundant. He typically notes the justification and consistency problems that would arise from a commitment to the Kantian thing in itself, and then immediately goes on to say that therefore the given, or the phenomena of affection, do not require the existence and contribution of a mind-independent world. The fact that justification and inconsistency problems around a commitment to a mind-independent world is a sufficient reason for abandoning it coheres well with skepticism in the sense of disappointed realism.²⁰

There is a further statement in the Essay—part of which could be cited as evidence for the historically dominant reading—which actually makes very good sense from the perspective of the proposed alternative. In the context of presenting his ‘immanent’ account of affection, Maimon writes:

[1] To claim that intuition is analogous only to intuition and not to the thing itself is to completely cancel the concept of intuition, i.e., of the relation of a determined object to a determined subject. [2] Indeed it is impossible to prove that intuitions are the effects of something outside ourselves [3] so that if we want to go by our consciousness alone, then we must accept transcendental idealism, in other words, we must accept that these intuitions are merely modifications of our I, modifications that the I itself produces, but produces as though they were produced by objects completely different from us. (GW 2: 201–02)

In the first part of this passage, in [1], Maimon seems to be embracing a very realist intuition as to what an adequate conception of intuition (sensible representation) would amount to. As I read him, he says here that an adequate conception of sensible representations should involve a reference to the ‘thing itself’, which I take to be a mind-independent object. I read the first part of the passage as an expression of realist standards regarding what an adequate, non-skeptical account of our cognitive situation would amount to, i.e., as an explicit rejection of dispensability proper. But, in [2], Maimon goes on to note the justificatory problems that a commitment to such objects would raise: we cannot prove that such objects exist. This is the problem of skepticism; the standards cannot be fulfilled. (In the German version, I think it is clearer that the (demanding) kind of objects whose existence cannot be proved is the same kind of objects Maimon talked about in [1].)²¹ In [3], Maimon then goes on to present the project of developing a weaker account of sensible representations (the one that does not involve a reference to mind-independent objects), which I read as a conception that cannot and is not supposed to take over the function of the more adequate account presented in [1]. It is merely the impoverished conception we are entitled to within the context of a consistent skepticism, ‘if we want to go by our consciousness alone.’ This is the project of thinking of affection in a way that would be legitimate, without claiming that such an account makes the thing in itself dispensable as far as the standards of explanation set forth in [1] are concerned.²²

In sum, the Essay remarks express mere eliminability, while also suggesting an implicit rejection of the core claim that the standard narrative would have us expect, namely dispensability proper.²³ In the proposed reading, there is a deep similarity in the interplay of realism and skepticism in Maimon and Schulze. They are both realists regarding the standards for debates on reality. However, when it comes to the question as to whether these standards can be fulfilled, they are skeptics, and they are skeptics because they are realists.

Those familiar with Maimon’s ideas might hear here an echo of a familiar theme in Maimon’s thought (informed by recent, valuable interpretations thereof), which concerns the relationship between standards of explanation and their fulfillment, as expressed in Maimon’s distinctive combination of ‘rational dogmatism’ and ‘empirical skepticism’. In the next section, this issue will be at the center of my approach to Maimon’s explicit criticism of Schulze, which will bring into relief an important way in which Maimon’s views, despite significant points of convergence, depart from the views of contemporaries like Schulze—but not in the way the standard narrative would have us think. By bringing Maimon’s explanatory rationalism into play and connecting it to skepticism, I argue that, while both Schulze and Maimon operate within a realist framework, they are set apart by Maimon’s even higher standards.²⁴

3. Criticism of Schulze in the Logic: Maimon’s System of Rationalism, Skepticism, and Realism

In his Fourth Letter to Aenesidemus, in the Appendix to his Logic, Maimon criticizes Schulze’s take on the Kantian thing in itself rather explicitly. In this particularly weighty type of (alleged) evidence for the historically dominant reading, Maimon is standardly taken to argue against Schulze’s realist assumptions.

The statement I want to focus on is a prominent remark on the explanatory value of an appeal to Kantian things in themselves. In Aenesidemus, Schulze (1792: 164/[232–33]) presents the example of a tree and a house in order to illustrate the following phenomenon: perceiving subjects often find themselves in a kind of mental state with a very specific representational content, on which they seem to have no influence. For instance, when I open my eyes and find myself representing a house as opposed to a tree, I have no option with respect to the representational content of my perception. A possible explanation for this phenomenon would invoke the mind-independent world: the fact that there is indeed an object out there (for example, a house instead of a tree) that accounts for the fact that my perception has the specific representational content (house, not tree) that it has.

In his Fourth Letter to Aenesidemus, Maimon reacts to Schulze’s example by stating the following:

But what do we explain with respect to this through the assumption of things in themselves outside our representations? Will the poor Indian not just pose his question yet again by asking: And the tortoise, on what does it rest?²⁵ The question is this: why do I have right now the representation of a house and not one of a tree, which for example I could also be having; and why do I represent the manifold in this order and connection, given that I can also represent it in a different order? And the answer is this: because the house as a thing in itself exists now in this order and connection. But shouldn’t we ask ourselves further: why does the house in itself exist right now and in this particular order and connection, given that something else could exist instead of it? Once again, here is the case of a deceptive mistake which is caused by an erroneous concept of ground [Grund]. (GW 5: 429/[371])

The passage is commonly read as a crystal-clear affirmation of dispensability proper. As in the case of the Essay remarks, Maimon’s critical statement on the explanatory value of things in themselves is taken to imply the availability of an alternative account, which, while not invoking the mind-independent world, presents us with an adequate explanation for the phenomenon at stake. For instance, in Bergman 1967: 13–6, the passage is taken to express Maimon’s project of ‘removing’ the thing in itself while retaining its function as ‘the source for the content of consciousness’ and ‘the basis of truth’.²⁶

I think, instead, that Maimon’s reaction to Schulze is motivated by a combination of ‘pre-Kantian’ explanatory rationalism and skepticism, and does not imply that we could dispense with the mind-independent world in a satisfactory, non- skeptical account of our cognitive situation. I first articulate this kind of view as a live philosophical option, and then proceed to argue, on more textual grounds, why we should attribute it to Maimon.

Philosophically speaking, a dispensability-proper claim about the thing in itself is not implied by what Maimon says. We could imagine, for instance, an explanatory rationalist who endorses the following set of claims:

Explanatory rationalism: Good explanations give (non-trivial) answers to all (relevant) ‘why’ questions. In a good explanation, no brute facts are accepted. For every (relevant) true proposition p, a sufficient reason has to be given as to why p.²⁷

An advocate of such a view would not treat mental states with a specific representational content as a brute fact; they would seek an explanation. Moreover, they would place high demands on what a satisfactory explanation should look like: for example, they would not be satisfied if the explanation simply invoked an unspecified thing in itself the way this occurs in the Kantian model. For the explanatory rationalist, such an explanation would be insufficient and not good enough: the rationalist would expect an explanation for the further fact that we just introduced, and so on and so forth. Good explanations have to be ‘all the way down’. Moreover, the rationalist would expect us to explain how exactly the explanandum flows from the explanans; they would want to know ‘the way in which it comes into being’.²⁸ Explanations have to be fully transparent.

Explanatory rationalism could explain the difference between Schulze and his critic as it emerges in the Fourth Letter. For Schulze, a mere appeal to an unspecified thing in itself would be a sufficient, fine explanation for the matter at hand. Schulze is not an explanatory rationalist. His quarrel with the role of the thing in itself stems exclusively from other concerns. In Schulze’s view, a belief in the existence of (even unspecified) things in themselves is not justified, and is incompatible with the rest of the Kantian framework, so that this—in his view—fine explanation cannot be neatly integrated into the Kantian story. In contrast, the rationalist goes beyond such justificatory and compatibility concerns by raising a further, new challenge that turns on explanatory concerns too.

The question then is whether someone could disagree with Schulze on that front (and thus express critical views on the explanatory value of an appeal to things in themselves within the course of the Kantian model—as Maimon clearly does) while still thinking that the thing in itself is in a sense necessary and not dispensable.

From a philosophical perspective, this could clearly be the case. We could imagine an explanatory rationalist who criticizes the appeal to the thing in itself the way it occurs in the Kantian model, while still thinking that an alternative, ‘immanent’ explanation which does not invoke it at all would be inadequate too. Our rationalist could instead be holding the view that any satisfactory, non-skeptical explanation should assign a role to the mind-independent world as an explanatory ground. However, in contrast to the Kantian model, this role should take the form of a transparent and all-the-way-down explanation, which shows us how exactly experience originates from the mind-independent world.

In this type of view, the thing in itself would still be necessary—again, as in the case of Maimon’s Essay remarks, we have to tread carefully when formulating the relevant sense of necessity and indispensability here. The thing in itself would be necessary in serving as an indispensable explanatory ground in an adequate, satisfactory, and non-skeptical explanation; we do not ban it as a standard. However, in contrast to indispensability arguments in contemporary philosophy, and in line with skeptical concerns, this does not mean that such an explanation is available. The version of explanatory rationalism I sketched above is a view concerning standards of explanation; this is compatible with skepticism with respect to the possibility of fulfilling those standards. There is conceptual space for a combination of rationalism, realism, and skepticism.

I have articulated this alternative reading as one possible view in the conceptual space, but, in a second step, I want to bring into play a set of textual considerations that strongly suggest that this is indeed Maimon’s view.

There is something striking about the interaction between Maimon and Schulze in the Fourth Letter. From the perspective of the historically dominant reading, the interaction goes like this: Schulze brings up the appeal to a mind-independent world as a possible explanation for the fact that our perception (of a tree, rather than a house) has the specific representational content it has; in reply to this, Maimon declares such an appeal explanatorily redundant, along the lines of dispensability proper. Now, if that is indeed what Maimon is doing in this passage, then we would expect him to provide an alternative, equally good, parsimonious (antirealist) explanation for this phenomenon, namely why we perceive a tree instead of a house. Interestingly, Maimon does not do anything of the sort in the context of his criticism of Schulze—this makes his reaction to Schulze dialectically unsatisfactory. We merely get a declaration of Maimon’s opposing view, with no argument supporting it. While this observation cannot in itself rule out a certain reading—perhaps Maimon did in fact react to Schulze in a dialectically unsatisfactory way—it should nonetheless alert us to the possibility that we might be wrong in following the standard reading in the first place. Considerations that turn on the dialectical adequacy of Maimon’s reaction to Schulze could help us become more sensitive to textual evidence that does have the potential to settle the question as to which reading is preferable.

And, indeed, if we look more closely, we do find some evidence that Maimon is a skeptic with respect to our ability to explain the phenomenon discussed here. He does not offer an alternative explanation because he does not think that such an explanation is available. The passage from Maimon that we have been discussing here continues like this:

Ground [Grund] never refers to existence, but rather to cognition, and it is only the unity through which the manifold of our cognition is connected, in accordance with the laws of the faculty of cognition. The universal is the ground of the particular in our cognition. The ground on which we have to think, for instance, of a triangle as limited, is because we think the triangle through the concept of figure, and we determine ‘figure’ as a limited space. Through this ground we refer this cognition not only to the triangle, but rather to all objects that the concept of figure contains. These different cognitions are thus connected through their common ground. Likewise, the principle of determinability is according to me the ground for the cognition of all real objects. (GW 5: 429/[371–72])

This is a difficult passage, and I only want to call attention to the last sentence and Maimon’s explicit reference to the principle of determinability. The principle is presented by Maimon as his original contribution to philosophy, and plays a prominent role in the Logic, in which the Letters to Aenesidemus are included as an Appendix. The whole principle and its interpretation are complicated matters that could potentially appear irrelevant for our purposes here. But this is precisely the problem: why does Maimon suddenly mention the principle in this context? While refraining from any analysis of the principle, I wish to link my discussion to this complicated matter in order to merely establish the following claim: from the perspective of the standard reading, we cannot satisfactorily explain the sudden reference to the principle; by contrast, if we abandon that reading, the reference makes sense, and provides indirect confirmation for the reading I propose.

The principle of determinability formulates the conditions to be fulfilled in order for a proposition/belief to qualify as ‘real thinking’, as opposed to ‘arbitrary’ or merely ‘formal thinking’. Sticking to an uncontroversial summary of aspects of Maimon’s theory directly relevant for our purposes here, the following core features of the principle are noteworthy:²⁹ (i) A proposition/belief qualifies as real thinking if I can explain/justify why p is true (to this end, an appeal to the law of contradiction is not sufficient, since the principle is a principle for synthetic, not analytic propositions); (ii) the fulfillment of the conditions set forth by the principle of determinability is the sufficient reason for considering a proposition (which is not true just in virtue of the law of contradiction) to be true;³⁰ and (iii) paradigm cases for propositions that fulfill the conditions of the principle and count as instances of real thinking are mathematical examples³¹—by contrast, examples that concern the empirical world are classified as instances of arbitrary thinking.³²

What does all this have to do with the question of the thing in itself? Let us recall the phenomenon discussed by Schulze, addressed in Maimon’s critical remarks: we are concerned with representations of trees and houses. The respective propositions would clearly be synthetic propositions about the empirical world. (Think of something along the following lines: ‘What I am representing right now is a house, not a tree’; no matter what the propositions expressed are exactly, the important point is that they are not analytic, and that they concern empirical entities.) Although the details of Maimon’s overall position remain murky, so much is clear: synthetic propositions about the empirical world do not fulfill the conditions set forth by the principle of determinability. We cannot provide sufficient reason for the truth of such propositions.

If we interpret Maimon’s reaction to Schulze along the lines of dispensability proper, it is hard to make sense of the sudden reference to the principle. Its invocation could appear dialectically disappointing and off topic. If Maimon is in the business of providing an alternative account, then he should have focused on providing an ‘immanent’ explanation for empirical phenomena—this is what we are interested in. The fact that one might have a nice, immanent, rationalist explanation that merely applies to mathematics, and not to the cases we are interested in, does not help us much.

However, if Maimon is not in the business of providing an ‘immanent’ account of the phenomenon discussed by Schulze (and in fact deems such an account inadequate and not applicable to this case), then the reference to the principle makes good sense and has an important argumentative function. Instead of pursuing the antirealist project of providing an alternative account, Maimon draws the attention of his readers to an important conclusion of his own theory, namely the fact that the status of synthetic propositions about the empirical world is somehow problematic. The reference to the principle is to be understood as an implicit statement of Maimon’s empirical skepticism with respect to the explanation for the phenomenon discussed by Schulze. This means that his project around the thing in itself is a skeptical one, and this skepticism is informed by Maimon’s rationalism about standards of explanation (expressed, among other things, in the principle of determinability). This contrasts with the antirealist reading.³³

Having argued that the Fourth Letter passage, instead of standing in the way of the reading I propose, actually supports it,³⁴ I now turn to a second, more general textual consideration in support of the proposed reading.

As noted in the Introduction, there is nothing new in attributing to Maimon a combination of rationalism and skepticism. In a famous remark in his Essay, Maimon describes his system as a combination of ‘rational dogmatism and empirical skepticism’ (GW 2: 432–34/[436–38]), noting that such a description could possibly also fit Leibniz’s—that is, a famous explanatory rationalist’s—system (GW 2: 433/[437]). Maimon scholarship has engaged intensively with the question of how one should understand this combination of views. In some very helpful accounts on which I draw, it has been argued that Maimon is an empirical skeptic because he is a rational dogmatist. This is the core idea of Paul Franks’ (2003) and Peter Thielke’s (2008) approach to this aspect of the Maimonian position: an explicit connection is established with questions of explanation and the principle of sufficient reason. Likewise, Karin Nisenbaum (2018: 58–106) explores how Maimon’s commitment to ‘infinite intelligibility’—i.e., to the idea that everything has or exists for a reason—informs Maimon’s criticism of Kant. In these accounts, Maimon is a skeptic because he has high standards with respect to explanation (demanding fully transparent, all-the-way-down explanations). Such standards can in most cases (outside mathematics) not be fulfilled, which leads to Maimon’s empirical skepticism.

It is not difficult to see that the ‘explanatory rationalist’ type of view I described above ties in very well with this kind of picture, and is partly inspired by it. And, as remarked in the previous section, the central point to my (preceding) analysis of ‘standards’ vs. ‘fulfillment’ coheres well with this picture. I think that this counts in favor of my account. Interpreting Maimon’s remarks in light of his own characterization of his ‘system’ is a virtue. For an advocate of such a system, it would be quite probable that the statement on the explanatory value of things in themselves is intended in a similar sense. Relatedly, the fact that my reading builds on existing commentaries on Maimon’s thought shows that, despite being an alternative, ‘revisionist’ reading, it is actually continuous with aspects of Maimon scholarship that are much less contentious. Taken in themselves, these points should make it easier for many readers to accept that the main claims put forward here are true, or at least on the right track.

However, invoking this well-known aspect of Maimon’s thought in the course of the project of this essay could appear to be a double-edged sword: would this not compromise the novelty of the proposed reading? Would this not make the main claims put forward trivially true?

It is important to get clear on why the proposed reading, despite its appeal to these well-known aspects and well-received interpretations of Maimon’s thought, departs from existing readings in significant ways. The first reason has to do with the context in which Maimon himself calls attention to his distinctive combination of dogmatism and skepticism, and, relatedly, the context to which its analysis in existing Maimon scholarship pertains. This context does not concern the problem that is the focus of this essay, namely the question of Kantian things in themselves. Maimon’s remark appears in the context of his critical engagement with the ‘quid juris’ problem, the problem of particular causal claims in Kant—this is not the question we are discussing here. Relatedly, when scholars ascribe to Maimon the combination of views just sketched (namely, rationalist standards of good explanation, which are taken to be unfulfilled, thus leading to skepticism), this also concerns precisely this separate problem, not the problem of things in themselves. When Franks, Thielke, or Nisenbaum ascribe to Maimon this kind of view, they do it in the context of a discussion of the relationship between Maimon and Kant, or Maimon and Hume, on the issue of causality. No link whatsoever is established with the further prominent strand of Maimon’s engagement with Kant, namely the problem of things in themselves. This means that even if the move I propose here consisted merely in making explicit how these ideas apply to the problem of things in themselves, it would still be useful, as these connections have not yet been explored and made explicit.

However, the move I propose does not consist in merely making explicit how one could apply thoughts from a different domain to the problem of things in themselves. It would be fair to think that many scholars would want to resist transposing the framework around discussions of causality and the ‘quid juris’ problem to the thing-in-itself strand. A widespread tendency in Maimon scholarship is precisely to keep these two contexts apart, and to understand Maimon’s skepticism around causality as arising at the level of appearances, quite independently of the Kantian distinction between appearances and things in themselves. In the historically dominant reading, Maimon’s ‘progressive’ version of skepticism turns on a Kantian ‘dualism’ within the realm of appearances (namely, dualism with respect to different powers of the mind, sensibility vs. understanding). Maimon’s point is taken to be that ‘a new basis for skeptical doubt arises even if we adhere to the spirit of the critical philosophy, eliminating all talk of representations corresponding to objects and putting the standard of truth within consciousness itself’ (Beiser 1987: 292).³⁵

Taken in isolation from the rest of what I have done here, an appeal to Maimon’s well-known rationalism and skepticism would hardly convince anyone to abandon the historically dominant reading of the thing-in-itself strand in Maimon. As a case in point, a look at the interpretation of this strand by a Maimon scholar on whose work on the ‘quid juris’ I have drawn here, namely Thielke, could be instructive. In an earlier piece at least, Thielke (2001: 106–07) seems to sympathize with a reading of Maimon along the lines of dispensability proper.³⁶ I think that this reflects how recalcitrant some aspects of the thing-in-itself strand in Maimon’s thought can be, and how no simple ‘extension’ of views attributed to him on more general grounds will do.

In order to effectively challenge the historically dominant reading, one needs to develop an account that accommodates different pieces of (recalcitrant) evidence into a coherent story, bolstered by positive textual evidence. I tried to do part of this in the previous section, where the heavy lifting was not done by appeals to Maimon’s distinctive combination of skepticism and rationalism, but rather by conceptual (and historical) reflections on issues of realism and dispensability claims, connected with a close reading of passages in Maimon’s Essay. Similarly, in the next section I present some further pieces of (positive textual) evidence that are independent of this ‘rationalism cum skepticism’ discussion. But even with respect to my focus in this section, conceptual work on issues of rationalism and realism, connected with a close reading of passages in Maimon’s Fourth Letter, was central to my argument. An appeal to Maimon’s ‘system of rationalism and skepticism’ and to interpretative proposals around this (such as Thielke’s), while fitting very nicely with all of that, and while providing us with valuable resources at this particular juncture of my overall argumentative strategy, would not, taken in isolation, suffice to establish the alternative reading.

4. A Note on Maimon’s ‘Theory of Differentials’ and Some Neglected Statements on the Indispensability of the Thing in Itself

Let us take stock. I have made a case for a more realist interpretation of Maimon’s approach to the Kantian thing in itself by focusing on two key types of passages (in the Essay and the Logic, respectively) that count as crucial evidence for the historically dominant reading that is my target here. My aim was to show that these influential passages can and, all things considered, should be read differently. While focusing on these passages, I also remarked on a number of occasions how my strategies extend to other cases too.

Does this mean that I have accounted for all relevant evidence supporting the historically dominant reading? No, it does not. In a tangential comment, I called attention to the fact that Maimon’s so-called theory of differentials could be thought to introduce some complications: in some (very specific, yet influential) passages from Maimon’s Philosophical Dictionary (from 1791) that were outside my focus here, and could seem to support the historically dominant reading, Maimon’s stance toward things in themselves seems to be inextricably linked with his theory of differentials and with interpretative controversies around it.³⁷ As I refrained from putting these (specific) passages center stage, I need to briefly comment on why doing so does not subtract from the plausibility of the overall interpretation developed here.

The whole theory of differentials is notoriously difficult to grasp, and its analysis lies outside the focus of this essay. Oversimplifying matters a bit —and trying to strike a fine balance between saying as much and at the same time as little as possible—the following aspects of Maimon’s theory are particularly noteworthy from the perspective of this essay: (i) differentials according to Maimon are infinitely small elements that have a limiting function—while differentials are non-sensible, sensible objects consist of or emerge out of them;³⁸ and (ii) this conception of differentials as infinitely small elements is in turn linked to Maimon’s conception of an infinite understanding.³⁹

While it is clear that Maimon’s conception of an infinite understanding is linked to his conception of differentials, clarifying this link is a difficult and contentious question, which has already caused lively debate in Maimon scholarship —and it is precisely here that complications enter with respect to the status of the thing in itself. Depending on how exactly we interpret Maimon’s theory on that front, it could either reinforce or, rather, undermine Maimon’s (alleged) antirealism.

In an interpretation of the theory that dominated scholarship for centuries, Maimon is taken to hold the following view: our own understanding is close to the infinite understanding, in being the source of differentials. The resulting picture would reinforce the antirealist interpretation of the status of things in themselves in Maimon: the source of sensible objects would be us, and the mind-independent world would hardly have a role to play.

However, this interpretation has been challenged. Achim Engstler (1990: esp. 149–89) has argued extensively that the source of differentials is the divine, infinite understanding (as opposed to our own understanding), whereas the proximity of our (finite) understanding to the infinite one should be located in our ability to cognize these non-sensible elements, which we did not ourselves produce. In this interpretation, the antirealist take on the status of things in themselves would be undermined. (The revisionist interpretation has not gone unchallenged, either, and it has been criticized as standing in tension with some aspects of Maimon’s thought.⁴⁰)

I have chosen not to discuss this difficult and contentious theory here. Although I am sympathetic to Engstler’s project, and see it as a natural ally to the project I pursue here,⁴¹ I think that going deeper into this dark and complicated matter ultimately does not make a difference for our purposes: the problem being not so much the content of Maimon’s theory of differentials, but rather its special status within Maimon’s thinking. It is often unclear to what extent Maimon presents this theory as a workable theory that he himself embraces—and, in later works, after the Essay and the Philosophical Dictionary, he seems to abandon it altogether. Against this background, it is difficult to settle the case for or against a certain interpretation. Even if one could successfully show that, in a certain interpretation of the theory, irremediable tensions and problems for Maimon’s thinking arise, this need not count against that particular interpretation, as the proponent thereof could retort that the tensions actually explain why Maimon ultimately abandoned the (correctly interpreted) theory.

If the evidence for or against a certain reading of Kant’s attitude toward things in themselves were to be located solely in passages whose interpretation would turn on a very contentious aspect of Maimon’s thought which Maimon himself ultimately abandoned, it seems to me that such evidence would not be good enough, and would not be able to tip the balance in favor of either type of reading. I think it is more rewarding to focus on passages regarding which even scholars like Engstler, who have questioned some aspects of the received interpretation of Maimon, agree that they present unambiguous evidence for Maimon’s antirealism.⁴² And this is precisely what I have done here. In dealing with the arguably weightiest and least obscure textual evidence for the historically dominant reading, I argued that it can and should be read differently. If an examination of the best type of evidence for the standard reading yields this result, then I think this does tip the balance in favor of the alternative.

I now want to conclude the case for the proposed reading by calling attention to some neglected statements by Maimon, which are very hard to accommodate in the historically dominant reading, but fit very nicely with the reading I propose. These statements are not to be found in Maimon’s major works, which partly explains why they have been (mostly) neglected so far.

In the first noteworthy passage (GW 4: 544),⁴³ Maimon speaks of two ‘main parties’ and disavows both. The first is the dogmatic party, which wishes to restore the ‘lawful sovereignty of metaphysics’; the other party, by contrast, ‘has released itself from the slavery of things in themselves’ and ‘wishes to create everything out of itself (the faculty of cognition) (although the foundation for this might be insufficient [obschon der Fond dazu nicht hinlänglich seyn möchte])’. This statement contradicts the historically dominant reading, which would have us expect Maimon to clearly subscribe to the latter party; instead, Maimon notes explicitly the insufficiency of an ‘immanent’ account.

In the second passage that stands out—comprising two letters to Lazarus Bendavid, not included in the standard edition of his works that scholars have most commonly been using until now—Maimon criticizes Fichte. Maimon (1800: 210) makes fun of a supporter of ‘F…an philosophy’—which is no other than Fichtean philosophy—who became ‘a speculative as well as a practical fool’ and despises all knowledge that does not ‘derive synthetically in a direct line from his I.’⁴⁴ While not referring explicitly to things in themselves, the statement turns on questions which lie at the heart of such debates (since the contribution of the ‘I’ contrasts with the contribution of the mind-independent world). The anti-Fichtean view expressed here ties in very well with the first passage—which does explicitly concern the thing in itself—thus giving us reason to interpret it along similar lines.

While these neglected statements would not in themselves suffice to rule out the historically dominant reading—since one could try to read them in a different way,⁴⁵ or dismiss their relevance altogether as too marginal and obscure—they nonetheless deserve attention and should alert us to the possibility that something might be off with the dominant reading. From the perspective of this reading, which attributes to Maimon a dispensability thesis that culminates in Fichte’s project,⁴⁶ the neglected statements sound rather puzzling. If an alternative reading, based on Maimon’s celebrated remarks on the Kantian thing in itself, as found in the major works, is able to accommodate them better, then this further bolsters the alternative account. This is what I have tried to show in this essay. I think that the overall resulting picture does decidedly tip the balance in favor of the proposed reading.

5. Conclusion: Maimon’s Place in the History of Philosophy and His Philosophical Significance

Does the overall resulting picture, and the way considerations on the relationship between Maimon and Fichte feed into it, mean that the standard narrative on the origin of German Idealism and on Maimon’s role in it is to be abandoned altogether? Not necessarily. Even if Maimon is as a matter of fact not an antirealist who upholds the dispensability of the thing in itself—and the standard narrative is indeed misleading in that respect—this is compatible with Fichte and other Idealists (mis-)reading him this way. The standard narrative could still be correct in assigning Maimon a special place in the history of this development of German Idealism: a role he would have played not in virtue of his actual views, but in virtue of the way these were fruitfully (mis-)understood.

Still, even if we accept this part of the standard narrative,⁴⁷ this would not make the question of getting Maimon’s views right any less important or interesting, quite independently of how other, influential thinkers read him. To draw a comparison, Kant scholarship nowadays mostly consists in recovering Kant’s actual views—often in opposition to the influential reception of these views—precisely because Kant is taken very seriously as a philosopher in his own right. I think that Maimon, a distinctive and important figure of German and Jewish philosophy, deserves the same. The following concluding remark on Maimon’s philosophical significance, as it emerges from the reading proposed here, will serve to further substantiate this.

Arguing, contrary to a very long tradition, that Maimon, like other early readers of Kant, does not endorse a dispensability claim with respect to the Kantian thing in itself might strike some as amounting to a certain degradation of Maimon’s original contribution to philosophy. Far from it. Besides the fact that Maimon’s approach is still quite original in my reading—as it rests on Maimon’s distinctive combination of explanatory rationalism and skepticism—the full force of the significance of this approach comes to the fore once we think about the implications of my reading for another strand of Maimon’s engagement with Kant, namely his (celebrated) ‘quid juris’ problem.

As was noted at different junctures of this essay, Maimon formulates a powerful criticism of Kant, the ‘quid juris’ problem, which concerns the epistemic justification for causal claims about specific empirical objects. The upshot of Maimon’s criticism is that Kantianism is ultimately vulnerable to a version of causal skepticism.⁴⁸ In the standard narrative of Maimon’s reading of Kant, it is this aspect of his reception of Kant that is skeptically motivated, and this aspect is assumed to have nothing to do with the question of things in themselves.

Now, I think that this influential interpretation of the ‘quid juris’ problem can be challenged too. Establishing a link between Maimon’s concern with respect to particular causal claims on the one hand and a realist intuition with respect to the role of the mind-independent world on the other hand would be a natural reading of Maimon’s diagnosis: relations and properties of the mind-independent world should place objective constraints on our claims about specific empirical objects; ascribing a role to the mind-independent world is indispensable. But in Kantianism it is very unclear how, given Kant’s ‘Copernican turn’, such properties and relations can feature in the epistemic justification for such claims. It is not easy to see how Kant can both stay true to the realist strand of his thought and accomplish one of the major tasks the Critique is supposed to accomplish, namely defeat Hume’s causal skepticism. In response to this tension, in (my interpretation of) Maimon’s reading, Kant is not invited to drop the indispensability claim about the mind-independent world; he is invited instead to concede that his system cannot defeat skepticism.

It is important to see that this concern does not amount to standard worries that turn on questions of the existence of and affection by a mind-independent world. We are talking instead about a worry based on a more demanding, guiding, epistemic role that the Kantian thing in itself has to play: relations and properties of the mind-independent world would have to place objective constraints and figure in the epistemic justification for particular causal claims.⁴⁹ Accommodating such a role within the Kantian system comes with a new, distinctive set of problems. Whereas research on Kant has a lot to say about the standard challenge against the Kantian thing in itself (questions of mere existence and affection),⁵⁰ it is less clear how one should deal with a more sophisticated version of the challenge that goes beyond such questions and sets the bar higher for an adequate defense of Kant. Such a (formidable) challenge merits attention from the perspective of Kant scholarship in our time.

In the overall reading of Maimon presented here, his contribution to the debate on the Kantian thing in itself is certainly not downgraded.⁵¹

Competing Interests

The author has no competing interests to declare.