Kant and Mendelssohn on the limits of the Enlightenment

. Kant’s conception of the Enlightenment, contrary to Mendelssohn’s, cannot be limited or constrained by designating a special sphere where ‘enlightened’ claims are applicable and another special sphere where ‘enlightened’ claims are not applicable. In contrast to some of the literature, I show that no single domain concerning human affairs is beyond Kant’s conception of the Enlightenment to the extent that no single domain is outside of reason. I show this to be the case by looking, first, at Mendelssohn’s conception of Enlightenment and its links to his understanding of moral progress and conscience. Because ‘Enlightenment’ designates the correct use of one’s own theoretical faculties, it is the task of formation ( Bildung ) to prevent the Enlightenment from extending beyond its legitimate domain. Thus, for Mendelssohn, the sphere of formation stands in stark opposition to the sphere of Enlightenment. I then look at Kant’s response to the question of what Enlightenment is and show that his deceptively simple answer is in fact underpinned, on the one hand, by a rather complex account of reason’s universality, public nature and communicability and, on the other hand, by a complex account of reason’s historical development. Kant’s conception of Enlightenment, unlike Mendelssohn’s, does not stand in opposition to a practical sphere insofar as Enlightenment designates the process of breaking away from immaturity ( Unmündigkeit ), a process the scope of which is necessarily unlimited.


Introduction
Both similarities and differences internal to the Enlightenment's self-understanding have been noted before. In the German context, specifically, the question of what the Enlightenment is, originally posed by Johann Friedrich Zöllner in a footnote of an article for the Berlinische Monatsschrift responding to Johann Erich Biester's views on the supposed role of religious ministers in marriage ceremonies, drove Zöllner to consequentially write: "What is Enlightenment? This question, which is almost as important as 'what is truth?', should indeed be answered before one begins enlightening! And still I have never found it answered" (Hinske, 1973, p. 115). 1 The similarities and differences in the answers the question elicited, in virtue of being answers to the same question and in virtue of coming from distinct thinkers with diverging philosophical commitments, would be nothing if not expected (Schmidt, 1989). Thus, Mendelssohn's response essay and Kant's response essay would, insofar as they were trying to answer the same question, share some common ground and would, insofar as they come from vastly different philosophical systems, differ in several regards, as Kant himself notes (WA, AA 08: 42n).
Although I think focussing on the similarities between Mendelssohn and Kant has proved productive, especially when that focus has been set in relation to Wolff (Guyer, 1991), in this paper I approach their conceptions of the Enlightenment by focussing on the differences. Insisting on these, what I hope to bring to light is that despite some similarities, the different Enlightenments that emerge in each case answer, first, to each thinker's interpretation of progress and of history and, second, to each thinker's interpretation of reason as such. I will do this by, first, looking at Mendelssohn's conception of the Enlightenment as the correct use of one's theoretical faculties and then moving on to the broader philosophical underpinnings that ground it. It will be seen that this notion of Enlightenment answers primarily to Mendelssohn's thesis on the lack of historicity of morality and secondarily to his thesis on individual conscience. I then proceed to discuss Kant's conception of the Enlightenment, understood as the emergence from immaturity, and, as before, move on to look at the broader philosophical bases that ground Kant's understanding of Enlightenment. Here, it will be seen that Kant's conception of the Enlightenment is based primarily on his understanding of reason's historical progress and secondarily on his understanding of reason's universality, publicity, and communicability. Once having looked at both thinkers' conceptions of the Enlightenment I set them in relation to one another, in the hope of showing their respective originality and mutual irreducibility. In this context, I briefly address a possible worry concerning the impossibility of ruling out that the publicity of reason is also, just as much as its authority, a common feature that both Enlightenments share. Though I agree that this might be the case to a limited extent, I counter that the publicity of reason as a necessary condition for Enlightenment is not in any case unique to Kant and Mendelssohn. Thus, just as much as emphasising reason's authority risks missing the different ways in which this authority is fleshed out, emphasising reason's publicity as a common property risks flattening out the originality of each of these thinkers' Enlightenment views.
The argument developed here will show, in contrast to some contemporary literature, that despite sharing some broad concerns regarding the authority of reason and the possibility of moral progress, Mendelssohn and Kant differ in the way they conceive of such authority, in the way they think the possibility of moral progress and, importantly, in the role they ascribe to the state in what Zöllner called in the quotation above 'enlightening'. The contrast between these two views makes it clear that Kant's Enlightenment project, unlike Mendelssohn's, is at least partly a political project: that of ensuring that the state provide the right conditions for its citizens to flourish. The same cannot be said of Mendelssohn's notion. For the latter, Enlightenment would overreach its legitimate domain, were it to encroach on morality and culture. For Mendelssohn, the Enlightenment is indeed progressive, but the scope of its progress should in principle be constrained to its theoretical dimension. Speaking, therefore, of the precise limits of the Enlightenment offers not only a precise grasp of the meaning of the term in each case but, moreover, a productive way of setting these two thinkers' mature philosophies in dialogue with one another.

Mendelssohn
i. In Über die Frage: was heißt aufklären? Mendelssohn writes that formation (Bildung), which has the vocation of human beings (Bestimmung des Menschens) as its aim (Mendelssohn, 1997, p. 313), may be analytically broken down into two: culture (Kultur) and Enlightenment (Aufklärung). While culture applies, objectively, to refinement and excellence in arts and trades and, subjectively, to proficiency and skill, Enlightenment applies, objectively, to rational knowledge and, subjectively, to rational proficiency. The contrast, according to Mendelssohn, between culture and Enlightenment can therefore be construed as the contrast between a broadly practical sphere, that of culture, and a broadly theoretical sphere, that of Enlightenment. But the vocation of human beings may be further divided into two parts: their vocation as human beings and their vocation as citizens. When it comes to culture, the distinction between the vocation of human beings as human beings and as citizens is not too difficult to track: one is in need of culture only to the extent that one is a member of a larger social body and, therefore, one is need of culture only as a citizen. When it comes to Enlightenment, however, the distinction is slightly less straightforward: the human being is in need of Enlightenment both as a human being and as a citizen: "The human being as a human being is not in need of a culture, but is in need of enlightenment" (Mendelssohn, 1997, p. 314). Theoretical knowledge is necessary for furthering one's own competence in, say, scientific matters as a human being in general, but this knowledge is necessary, also, in relation to one's citizenship. Because of this, Mendelssohn thinks, the Enlightenment of a people will be proportional to the degree, relevance, dissemination and rigour of the knowledge of its individuals, or what Mendelssohn calls 'rational proficiency'.
As both James Schmidt and Norbert Hinske have noted before, from the above it follows that the Enlightenment of human beings as human beings (Menschenaufklärung) can conflict with the Enlightenment of human beings as citizens (Bürgeraufklärung) (Schmidt, 1989;Hinske, 1981, pp. 88-89). Mendelssohn thinks, indeed, that theoretical excellence can lead, for example, to a complete undermining of the legitimacy of a state's constitution. Therefore, the vocation of human beings requires that culture be considered once more. Culture can prevent Enlightenment from overreaching or from extending beyond its theoretical domain and keep it constrained, so as to avoid that Enlightenment conflicting with our ethical or civic duties. As Mendelssohn puts it towards the end of the essay, when Enlightenment and culture "proceed at the same tempo, they are together the best means of defense against corruption. To ruin the likes of one of them is to be in direct conflict with the other" (Mendelssohn, 1997, p. 314).
ii. Although the Mendelssohnian philosophical corpus is too large to be reconstructed here in any detail, and although Mendelssohn's philosophical commitments are oftentimes at odds with one another, as Beiser (1987, p. 95) has noted, I think it is important to consider two of the philosophical grounds moving Mendelssohn to articulate the Enlightenment in the way discussed above: historical progress and the role of conscience.
In Jerusalem, from 1783, Mendelssohn (1983, p. 96) writes that "it does not seem to me to have been the purpose of Providence that mankind as a whole advance steadily here below and perfect itself in the course of time". Providence arranges things in such a way that perfectibility is not a property that befalls humanity as a whole but, rather, a property pertaining to individuals only. Further ahead he states that "[i]ndividual man advances, but mankind continually fluctuates within fixed limits, while maintaining overall about the same moral level in all periods" (Mendelssohn, 1983, p. 97). There is, for Mendelssohn, a certain immutability when it comes to moral progress over time: as individuals we may perfect ourselves morally through conscience but, because conscience is not the kind of thing we can impose upon others, this perfectibility will be applicable to individuals only. Also in Jerusalem, but now in the context of a discussion about the nature of right, Mendelssohn (1983, p. 61) claims that "[t]he right to our own convictions is inalienable and cannot pass from person to person". This is telling of his position since, as McQuillan (2014) has shown, conscience is something that pertains to individuals only and neither the state nor any other institution (no matter how 'rational') should have any kind of claim over it. As we will soon go on to discuss, this position differs from Kant's significantly. For Kant, reason's authority rules over individuals and, by implication, a thoroughly rational institution must out of necessity have claim over individuals' conscience. For Mendelssohn this simply cannot be the case: if culture is needed to curtail the ambitions of the Enlightenment project, it is precisely on the basis that such project risks undermining individual moral progress. As Altmann (1982) notes, Mendelssohn creates a direct link between conscience and culture, and that link belongs to a practical domain strictly outside the limits of the Enlightenment.

Kant
i. For Kant, famously, Enlightenment means human beings' emergence from their selfimposed immaturity (Unmündigkeit) (WA, AA 08: 35). Mirroring the assumption of the Idea essay, whereby history solely needs reason to emerge; for the process of enlightenment to take place all that is needed, according to Kant, is freedom. Not so much freedom understood as one's capacity to choose this or that course of action, but rather freedom understood as the capacity to make use of one's own rational faculties in the public sphere. Unlike Mendelssohn, Kant does not think that restrictions ought to be placed on the Enlightenment as such but, rather, on what he terms the private use of reason. That is, the use of reason that "a person may make in a particular civil post or office [with] which he is entrusted", unlike the use of reason "which anyone may make as a man of learning addressing the entire reading public" (WA, AA 08: 37; Kant, 1991, p. 55), can be constrained so long as the restrictions imposed upon it don't contradict the goal of the Enlightenment -namely, breaking away from the self-incurred immaturity. In the private use of reason, one behaves passively as a member of the social order and seeks to promote public ends. As Kant remarks, it would undermine one's civic duty to engage privately in a discussion on the nuances of the rationality, or lack thereof, of any given command that one ought to carry out while entrusted to, say, some public office. This is not the case while making a public use of reason where Kant explicitly encourages a rational engagement with whatever practices one carries out as part of a larger whole.
Several implications follow from the deceptively simple elucidation above. It is clear, for one, that Kant cannot uphold freedom as the sole condition for the Enlightenment without thereby also ascribing a certain degree of universality to it. To the extent that all free beings are rational beings -in virtue of the fact that the form of the moral law can only be given by pure practical reason -it follows that breaking away from the dependence of one's own reason on that of others is everyone's duty. It follows, as well, that because the correct forum for the deployment of one's own rational powers lies in the public sphere, reason cannot be stripped of its publicity without thereby sacrificing its integrity. The authority of reason in individuals ought to be promoted and safeguarded by what in the third Critique Kant calls "a lawful authority centred in a whole", i.e. the state (KU, AA 05: 432; Kant, 2007a, p. 261). Flikschuh (2004) and Sweet (2018) are, in this sense, right in insisting on Kant's considerable distance from strict libertarianism. To exercise one's own reason in the public sphere cannot mean to engage in the so-called marketplace of ideas. Instead, exercising public reason can only mean being able to lay claims (moral, legal, etc.) within or against the legitimate boundaries set by the state. Lastly, it follows from the above characterisation of the Enlightenment, understood as an emancipatory process, that such process will imply a form of communicating one's critical stance in an intelligible way. 2 ii. The Enlightenment understood thus follows, in my view, rather naturally from Kant's broader philosophical project. In the explication to the second thesis of the Idea essay (1784), written the year after the Enlightenment essay, Kant is unequivocal about the fact that rational and moral perfectibility does not occur at the individual level but solely in relation to all of humanity. Because of this, nature ensures that in generation after generation moral progress is passed down "in order finally to bring the seeds of Enlightenment to that degree of development in our race which is completely suitable to Nature's [own] purpose" (IaG, AA 08: 19; Kant, 2007b, p. 110). Emergence from a self-imposed immaturity is necessary to the fulfilment of history to the extent that, through continuous Enlightenment, a rational way of thought takes root which can over time transform our natural dispositions for moral discrimination into definite practical principles and "thereby change a society of men driven together by their natural feelings into a moral whole" (IaG, AA 08: 21; Kant, 2007b, p. 111).
This is further reinforced, in my view, in How to Orient oneself in thinking? (1786). In a footnote towards the end of the essay, Kant alludes explicitly to Mendelssohn's overly theoretical understanding of the Enlightenment and criticises it directly on the basis that it reduces a negative principle (i.e. think for yourself) to mere information acquisition (WDO, AA 08: 146). To make use of one's own reason, Kant thinks, is nothing more than to be able to ask oneself whether one is entitled to transform the ground upon which a certain assumption is based into a universal principle. Solely on this basis, therefore, Enlightenment is applicable just as much to theoretical cognition as it is to practical action (it is not an accident that the maxim above resembles the formulation of the categorical imperative, after all). And, as the first Critique makes clear, in the section on the "Discipline of Pure Reason", the only way to ensure that such principle can be enacted by individuals is by guaranteeing their right to make a free use of reason's critical powers for "it is quite absurd to expect Enlightenment from reason and yet to prescribe to it in advance on which side it must come out" (KrV, A 747 / B 775; Kant, 1998, p. 647) in any given dispute.
What this amounts to, ultimately, is that it is impossible for Kant to think of the Enlightenment as restricted in scope simply because of the link between social, moral, and historical progress and reason. The strongest evidence for this is perhaps found in the dialectic of the second Critique where Kant claims that if the moral law were unable to bring about the highest good in the world, then the moral law itself would be false (KpV, AA 05: 114). Kant is thus committed to a notion of moral improvement that leaves no room for ambiguity: the use of one's own rational faculties in virtually every domain of life is an imperative that we ought to abide by. Or, as Kant puts it in the Enlightenment essay: "One age cannot bind itself and conspire to put the following one into such a condition that it would be impossible for it to enlarge its cognitions (especially in such urgent matters) and to purify them of errors, and generally to make further progress in enlightenment. This would be a crime against human nature, whose original vocation lies precisely in such progress" (WA, AA 08: 39; Kant, 1991, p. 57).

Two versions of the Enlightenment
One recent attempt at setting Mendelssohn's and Kant's conceptions of the Enlightenment in relation to one another has come from Kristi Sweet. Sweet (2018, p. 131) rightly emphasises that the central question about the Enlightenment is a question of authority. Post-Reformation Europe found itself having to grapple with questions the nature of which was foreign to Catholic thought. Indeed, the Reformation had severed any kind of necessary connection between moral and political authority -especially the identity connection that Catholic Rome had espoused up until then. This lack of identity effectively created a vacuum whereby authority itself seemed anything but certain. Recalling Luther's purported replacement of the authority of the Church by the authority of one's own conscience, she argues that after the Reformation no single entity could act as ultimate arbiter in problematic moral, political, and epistemological issues: "The dissolution of its [the Catholic Church's] moral authority is at the same time the destruction of the ground of its political and epistemic authorities" (Sweet, 2018, p. 134). Thus, for Sweet the contrast between Mendelssohn's and Kant's notions of Enlightenment lies in that the former's "concept of conscience [unlike Kant's], which has authority over the inner life of individuals, does not provide the measure of what the external world must conform to" (ibid., p. 143). It would follow from this that, since moral progress depends on one's own individual conscience, and conscience is always conscience of a single individual, in Mendelssohn moral progress can at best be understood in the betterment of one's own life.
While I agree that this is a constructive way of framing the Enlightenment problem, especially insofar as it acknowledges both Mendelssohn's and Kant's recognition that the sovereignty of reason acts as the touchstone of truth (ibid., p. 135), I also think it risks losing sight of some of the more subtle aspects that differentiate these thinkers. The first of these is the different way in which each conceives of the universal authority of reason: while for Mendelssohn this authority is limited to theoretical endeavours, for Kant it goes so far as to encompass morality as well since it is through reason that we transform particular maxims into universal laws and a particular society into a moral whole. This should not be taken to mean that Mendelssohn therefore renounces all universality. As Eli Schonfeld (2018) has shown, one of the main components of Mendelssohn's mature philosophy consists precisely in trying to articulate universality and particularity as is evident in his insistence on the universality of religious eternal truths (Mendelssohn, 2018, p. 22). It should be taken to mean, however, that the latter's universality differs from Kant's. A second worry that arises in overemphasising the authority of reason concerns the risk of missing the different functions that Mendelssohn and Kant ascribe to the state. According to Sweet (2018, p. 139), on the grounds that Enlightenment may be hindered by a state keen on promoting the cowardice in individuals that precludes maturity, Kant's role for the state is fairly vague: the state may influence, either positively or negatively, Enlightenment in individuals. According to what was discussed above, however, it would seem that Kant's role for the state is more precise than that: to the extent that the state should be the lawful embodiment of reason's authority in the public sphere, it is a necessary condition in fostering the Enlightenment of individuals. Admittedly, the state's acting as such may take a negative role by simply not thwarting any individual's effort in the bringing themselves out of immaturity, but it can also take the more positive approach in actualising Enlightenment amongst its subjects by acting as guarantor of the publicity of reason.
Against this last point, perhaps it could be countered that at least since Biester's address, the publicity of reason criterion was already operative. Following the typical imagery of the Enlightenment, whereby truth drives out falsehood just as light drives out darkness, Biester had spoken of making superstitions public so as to preclude people from adhering to them (Schmidt, 1989, p. 278). Even Eberhard, a future critic of Kantian philosophy, was caught in the Geist of the Enlightenment as shown in his inquiry into the origins of superstition. To this I would respond, first, that, even if such were the case, this would only go as far as to show that indeed the publicity of reason is a common feature to both Mendelssohn and Kant. It would not show, however, the state's role in safeguarding such publicity as a common feature nor that rational historical progress is something that both thinkers endorsed. But I would also respond, secondly, that such a position would risk transforming the controversy between Kant and Mendelssohn into but an echo of the Mitwochgesellschaft controversy between Möhsen and Zöllner. After all, while Möhsen, too, seems to advocate an ever-fartherreaching Enlightenment, Zöllner is much more cautious and prefers to restrict the limits of the Enlightenment to scientific inquiry. The richness of Kant and Mendelssohn's differences would be lost eo ipso in siding with this objection.

Conclusion
Apart from drawing attention to the differences inherent in the Enlightenment's selfunderstanding, hopefully the discussion above has also served to clarify the distinct ways of conceiving of the authority of reason, of the role of reason in historical progress, and of the role of the state in relation to Mendelssohn's and Kant's Enlightenments. While it is true that both thinkers agree in granting authority to the sovereignty of reason, they differ in the roles they ascribe to such authority. While Mendelssohn advances a view of the Enlightenment as a movement that needs to be constrained in its scope so as to avoid having it trample upon the domain of culture, i.e. a moral domain, Kant advocates a view inextricably linked to the necessary progress of reason. For the latter, not only is there no conflict between reason's theoretical and practical progress, but furthermore, the two forms of progress are interdependent.
Simplifying the above even further: whereas Mendelssohn's Enlightenment cannot take place but as limited progress in theoretical cognition, even when this progress itself improves our condition as citizens of any given polis, Kant's Enlightenment cannot but take place as unrestrained or unlimited progress towards the constitution of a moral whole. The fact that both conceptions of the Enlightenment seek to shed light on reason as a source of authority should not obscure the further fact that each conception spells out that authority in different ways. Unlike for Mendelssohn, for Kant the Enlightenment of individual rational agents taken as members of a larger social whole does not involve any kind of tension. Instead, for Kant, the Enlightenment of individuals is connected to the Enlightenment of the social whole to which those individuals belong. Kant offers, according to this, a rather comprehensive picture of the Enlightenment that rejects the betterment of individuals in isolation: to bring oneself out of maturity is to be able to recognise that we owe it to others to do the same for them. It is in this sense that, whereas Mendelssohn cannot uphold his conception of the Enlightenment without curtailing it, Kant cannot uphold his conception of the Enlightenment without totalising it.