One of the few areas of philosophy in which Kant’s ideas are not generally regarded as highly significant is social philosophy. Modern social philosophy tends to draw more frequently and intensively on other thinkers, such as Rousseau or Hegel. In contrast, Daniel Stader’s Unmündigkeit: Kant und die soziale Dynamik der Aufklärung seeks to reinterpret Kant’s philosophy by highlighting its relevance to social thought. He thus follows in the tradition of Allen W. Wood (Reference Wood1999: ch. 9), who emphasised early on the social-theoretical content and implications of Kant’s work. What sets Stader’s book apart, however, is the focus on the concept of immaturity as the interpretative key to uncovering the social-philosophical dimensions of Kant’s thought. By adopting this focus and integrating meticulous source analysis, particularly of the anthropological corpus, Stader brings to light previously neglected aspects of Kant’s Enlightenment philosophy, providing a topical framework for contemporary social criticism. In the following, I reconstruct the key arguments presented in the book’s introduction, six substantive chapters, and conclusion, adding some queries at the end.

The introduction begins by directly addressing the concept of immaturity, setting the direction for the study. Kant defines a person as ‘immature’ when that person allows their thinking to be guided by others. Stader first highlights that this notion takes on particular significance under specific social circumstances, suggesting that Kant’s notion relates to ‘the conditional, factual thinking of human beings’ (p. 40; here and throughout my translation). Consequently, Stader cautions against interpreting the concept of immaturity through the lens of Kant’s pure moral philosophy (cf. Louden Reference Louden2000). Instead, he advocates for his anthropology as a more suitable framework for interpretation, concentrating on the corpus in which the concept is explored more thoroughly than in the printed writings. Although this perspective proves to be highly productive, I view the exclusion of the connection between the empirically grounded notion of maturity and the concept of autonomy originating from Kant’s ethics as a critical oversight. I will address this issue, along with my two other queries, in more detail following the reconstruction.

In the first chapter, Stader contrasts the view of enlightenment as ‘man’s emergence from his self-incurred immaturity’ (‘What is Enlightenment’, 8: 35) with the prevailing understanding of the period. Whereas Mendelssohn and the Berliner Mittwochsgesellschaft on the whole treated enlightenment as the correction of error, Kant formulated what Stader calls a ‘formal concept of enlightenment’ (p. 50). In this view, enlightenment does not mean replacing false beliefs with true ones, nor is its success measured by the quantitative increase of knowledge. For Kant, enlightenment instead names the process of acquiring the distinctive mode of thought of thinking for oneself. Stader further traces this formal shift through Kant’s well-known distinction between ‘learning philosophy’ and ‘learning to philosophize’ and his particular conception of logic. He situates these developments within a broader history of ideas, drawing, among other sources, on Wolff’s account of libertas philosophandi.

In the second chapter, Unmündigkeit again works in terms of the history of ideas, tracing a ‘dynamization of faculties’ along the theory of prejudice. Stader begins with Descartes and Thomasius, who adopt an ontogenetic account of how prejudices arise, and moves to Locke, who emphasises the influence of contingent conditions on their development and the role of practice in overcoming them. From there, he turns to Meier, who, as both earlier and later in the study, is treated as a precursor to Kant because of his formal view of prejudice. This trajectory culminates in Kant’s notion of prejudicial thinking taking root in the formation of human faculties. For Kant, Stader writes, prejudice is ‘a deficiency in the use of one’s own understanding that has become the rule’ (p. 146) – a definition that parallels the concept of immaturity. Building on this, Stader shows how Kant’s reworking of the theory of prejudice supports the establishment of judgement as a distinct faculty and anthropology as a separate discipline. Regarding anthropology, Stader distinguishes three stages in Kant’s work, the second of which, as found in Anthropologie Friedländer, is of particular significance. Here, Kant casts ‘immaturity’ as a critique of intersubjective, social domination: ‘“(Im)maturity” does not refer to an individually attributable capacity to be able (or unable) to use one’s own faculty, but to this capacity as an interpersonal relation of dependence or independence’ (p. 186). With this, Stader arrives at the main theme of his book: Kant’s social-philosophical reflections on ‘(im)maturity’.

The third chapter systematises these reflections and represents the central chapter of the book. After once again grounding his discussion in the history of philosophy, Stader defines ‘immaturity’ as ‘epistemic dependence’ (p. 215): immature individuals are unable to judge ‘true’ and ‘false’ or ‘good’ and ‘bad’ without the guidance of others. This framing makes clear that the underlying idea derives from the parent-child relationship. Also, Kant repeatedly employs the metaphor of learning to walk to illustrate the precise import. For him, immature individuals resemble children confined to a baby walker by their guardians, unable to develop independent walking. Here, however, a key question arises: Why, then, is immaturity described as ‘self-incurred’? My second concern is that Stader does not provide a fully satisfactory answer to this. What he does clarify is a very important pedagogical implication: guardianship in education is legitimate only insofar as it aims at its own eventual abolition. He further shows how Kant’s framework can be used to attack self-legitimising forms of guardianship that refer to their own effects – i.e., the epistemic dependence of those subjected – to justify this very subjection. At the end of the chapter, Stader presents Kant’s sexism as a ‘deliberate positioning’ (p. 279). One might be tempted to argue that, by claiming that women naturally require guardianship, Kant commits the very error he otherwise condemns.

Building on the preceding discussion, the fourth chapter offers a commentary on Kant’s ‘What is Enlightenment?’. Stader situates the essay in the context of the anthropological corpus and follows Kant’s ‘constant broadening of perspective’ (p. 297) from the level of individuals to the public sphere and, from there, to the present age and finally to history in general.

History in general is also the focus of the fifth chapter, examining man’s emergence from self-incurred immaturity as a phylogenetic process. The chapter starts with a discussion of Rousseau’s Second Discourse, which Stader identifies as a foundational influence on Kant’s philosophy of history. He then highlights three dimensions of immaturity in Kant: ‘domestic’ immaturity concerns education and thus the adult-child relationship; ‘civil’ immaturity refers to legislation and the relationship between rulers and the ruled; finally, ‘pious’ immaturity pertains to religion and the relationship between clergy and believers (p. 368). According to Stader, Kant conceives of the gradual overcoming of immaturity in history as unfolding across these dimensions, namely through cultivation, civilisation, and moralisation. From this, we can, I think, derive a Kantian notion of intergenerational responsibility: each generation has a duty to improve the initial conditions (dis)enabling subsequent generations to emerge from immaturity ontogenetically. The chapter closes by arguing that Kant systematically implements a racist stance in this part of his oeuvre. As Stader interprets him, Kant maintains that human ‘races’ have historically followed unequal paths of development of their capacities and are therefore differently capable of becoming mature. In line with this, Kant characterises ‘negroes’ as children incapable of self-governance (Refl 1520, 15: 877). My third query intersects with this repeated equation of supposedly immature people with children. It is primarily directed at Kant himself: in addition to sexist and racist attributions, his association of immaturity with youth also warrants critical scrutiny.

Finally, the sixth chapter traces the concept of (im)maturity in post-Kantian philosophy. After having been supplanted by the concept of emancipation, Stader detects a revival of the concept in the Frankfurt School, particularly in the work of Adorno. This reference to the Kantian legacy in Critical Theory is both accurate and important, especially given how often it is overlooked. However, Stader then advances a fundamental criticism of Habermas, accusing him of pursuing an anti-Kantian and anti-Enlightenment agenda. I find this assessment mistaken, though I do not wish to make it a central concern here. The imbalance in his critique becomes evident not least in the argumentative effort and benevolence with which Stader afterwards draws a connection from Kant to Foucault through the notion of pastoral power.

From the conclusion embedded in the last chapter, I will pick out just one assertion to lead into my three main remarks. There, Stader summarises: ‘The emergence from self-incurred immaturity does mean arbitrary use of one’s faculties’ (p. 501).

1) Although I consider this statement accurate, I believe Stader’s interpretation lacks the resources to distinguish the ‘arbitrary use of one’s faculties’ from their ‘proper’ use. This shortcoming arises from the fact that, for him, the concept has no points of contact with Kant’s ethics. Yet the observation that ‘maturity’ should not be equated with ‘autonomy’, as he rightly notes, does not imply that the social-philosophical idea is unrelated to the moral-philosophical one. In ‘What Is Orientation in Thinking?’, Kant in fact connects the enlightenment idea to a universalisability test from the Groundwork of the Metaphysics of Morals, and thus to the most essential aspect of his ethics, noting: ‘To employ one’s own reason means simply to ask oneself, whenever one is urged to accept something, whether one finds it possible to transform the reason for accepting it, or the rule which follows from what is accepted, into a universal principle governing the use of one’s reason’ (‘Orientation in Thinking’, 8: 146). Of course, the passage does not provide a detailed account of how this connection operates. Nevertheless, it seems to me that without such a link, there would be no independent criterion for the proper use of one’s faculties. Stader’s benchmarks – ‘The use of one’s faculties must be formed and measured by one’s own experience; it must be subjected to reflection and discussion’ (p. 501) – are not sufficient by themselves. In the absence of a standard set by reason, experience, reflection and discussion can lead to error when distinguishing ‘false’ from ‘true’ and ‘bad’ from ‘good’. For instance, showing why superstition or belief in conspiracy theories conflicts with thinking for oneself requires a stricter standard. For Kant, this standard derives from a principle of universalisability. Consequently, moral philosophy is indeed relevant to his notion of enlightenment. Systematically connecting these two domains of his thought, however, remains a task yet to be undertaken.

2) The second remark is related to this. Stader’s book does not make entirely clear what decisive significance the attribute ‘self-incurred’ carries for Kant. Stader rightly stresses that it marks a distinction from ‘natural’ immaturity, such as that of children – a point to which I will return shortly. He also demonstrates that the attribute by no means excludes the role of external circumstances in sustaining immaturity. Indeed, one of the principal merits of his study is to illuminate the social conditions that foster dependent thinking. What Stader does not sufficiently examine, however, is to what extent it is meaningful to speak of ‘self-incurrence’ at all in light of restrictive educational, political, and religious circumstances, which in my view is precisely what Kant has in mind. Instead, this issue is relegated to a footnote:

Once again, the conclusion is correct, but the reasoning behind it remains inadequate. Kant indeed explored how the possibility of freeing oneself from alien guidance can be justified even in the face of adverse circumstances, namely, in his ethical thought. Here, too, his ethics, and in this case his concept of freedom, prove pivotal to understanding his idea of enlightenment. The attribute ‘self-incurred’ expresses the conviction (or the hope) that even unfavourable social conditions cannot entirely hinder people from thinking for themselves.

3) As noted above, Kant’s antonym for ‘self-imposed’ immaturity is ‘natural’ immaturity, the paradigmatic case of which is the child, both for Kant and for other Enlightenment thinkers before and after him. Kant clearly underpins his concept of enlightenment with a coming-of-age metaphor (Green Reference Green and Schmidt1996). While he does not maintain that being an adult automatically means being mature, he nevertheless regards adulthood as a prerequisite for maturity. I find this view problematic in two respects, and Stader’s study is only one of numerous examples which reconstruct it too uncritically. First, we must ask whether, and if so to what extent, social circumstances also shape the immaturity of children and young people in general. This is not to suggest that attributing immaturity on the basis of youth is as concerning as doing so on the basis of sex or race. Nevertheless, there is also a risk of naturalisation when children as such are judged ‘naturally immature’ (Anth, 7: 209). Moreover, this issue relates to Kant’s ontogenetic teleology, which links moral progress to the attainment of certain ages. Second, in Kant, the attribution of immaturity legitimises strong political and social paternalism toward children (see, for example, ‘Theory and Practice’, 8: 290–1). This prima facie creates a tension with Kant’s pedagogical thought, where he develops a gradualist understanding of how individuals achieve maturity. It appears that he advocates a categorical distinction in one domain and a gradual one in the other, with different normative statuses for children as the result. The question is what underlies this distinction. In my view, these problems warrant more in-depth investigation.

Unmündigkeit is a book well worth reading. It demonstrates a deep engagement with an aspect of Kant’s thought that has hitherto received insufficient attention. The analysis of the social conditions giving rise to immaturity makes this work a significant contribution to Kant scholarship as well as to social philosophy. Given current social developments, the relevance of the subject cannot fail to strike the reader repeatedly. In this light, the concerns raised should be understood primarily as stimuli for further discussion. They illustrate that, while Stader’s book takes us a considerable step toward unlocking Kant’s thought in the present day, we are by no means at the end of the road.