Legal terminology and metaphor are pervasive in Kant’s Critical philosophy, so much so that terms like ‘lawfulness’ or ‘deduction’ tend almost to fade into the background as just so much jargon that the Kant scholar feels at home using. Sofie Møller’s book encourages us to stop and take note of this terminology. Her task is to bring Kant’s legal terminology and metaphor to the foreground to assist in a better understanding both of his Critical project, and of individual arguments within that project. As such, Møller takes Kant’s choice of metaphor seriously, and interprets his choice of terminology as more than just a helpful illustration or heuristic, but rather as a clue into the very structure of Kant’s system. Necessarily, for such a project, Møller also offers the reader a detailed and historically rich account of the legal terminology that Kant adopts or references.

Møller’s book is a wonderful antidote to the sense one sometimes has, even when one reads Kant in the original, that one is still reading a slightly different and distant language. Of course, once the reader has been properly educated about the meaning behind Kant’s legal metaphor and terminology, there is still an interpretative choice for her to make, namely, how literally or closely to follow these metaphors in interpreting Kant’s arguments. Møller’s interpretative choice tends to be to take them very seriously. On her view, Kant is not just using familiar legal terminology loosely, adjusted to this or that extent for his own purposes. Rather, Møller interprets Kant as using these metaphors relatively strictly, for example, allowing facts about the legal tradition of Kant’s time to explain the structure of various Kantian arguments. At the same time, Møller is also careful to point out where analogies are not perfect. On the whole, however, she opts for an interpretation of Kant’s use of these terms according to which they are generally reliable and fairly literal clues into the nature of his argumentation. This is most apparent in the chapters of the book that focus on the transcendental deduction (chapters 3 and 4).

Chapters 1 and 2 of the volume offer an interpretation of Kant’s account of ‘normative lawfulness’ (p. 13). Chapter 1 interprets Kant’s Critique of Pure Reason as a tribunal of reason – particularly important here is the sense in which rightful claims to knowledge can be distinguished from mere pretensions via appeal to a law (pp. 18–19). Møller further sees the Critique of Pure Reason as establishing a ‘rightful condition analogous to the establishment of a civil state’ when it comes to claims to knowledge (p. 17). Just as the state of nature is a state of ‘lawlessness and general insecurity’ (p. 22), so, too, is reason in a state of nature without the critique of pure reason. Though Kant uses the metaphor of a battlefield to describe this condition (Aviii), Møller herself is careful not to overstate the chaos that the state of nature threatens, either socially or with respect to the pretensions of reason: the major threat to both is that of uncertainty and the impossibility of progress. Møller even extends the point to a possible analogy with Kant’s notion of perpetual peace – just as international peace is secured by each state existing in a rightful condition, peace ‘among metaphysicians is guaranteed by their inner observance of valid laws’ (p. 26). Of course, it is not clear how perfect this analogy can be, since, as Møller herself acknowledges (p. 25), peace among rightful states is guaranteed by the fact that it is not in the interest of the members of those states to go to war. Chapter 2 of the book includes an interesting discussion of the development of use of the term ‘law’ in the natural sciences. Again, Møller interprets the terminology as more than just useful shorthand: ‘Since the laws of nature are imposed rather than immanent, Kant can adopt this model by changing the legislator and replace God as the prescriber of laws with reason’ (p. 39).

Of course, the moment in Kant’s Critical philosophy where legal metaphor and critical argumentation come to a point most obviously is the transcendental deduction. Chapters 3 and 4 concern themselves with Kant’s account of the ‘lawful authorization to judge’ by offering a critique of a dominant interpretation of the role of the transcendental deduction and a novel interpretation of the B-Deduction. According to Dieter Henrich, we should read the deduction as a search for a claim to a title (i.e. the entitlement to use the pure concepts of the understanding). As such, the argument should be evaluated according to legal standards, and not the standards of logical deduction. On this account, the metaphysical deduction answers the quid facti question, while the transcendental deduction answers the quid juris question. In particular, it answers the quid juris question by searching for an account of the origin or heritage of the pure concepts of the understanding. Møller argues instead that the interpretation of the quid juris question of the transcendental deduction ought to be informed by Kant’s understanding of judicial imputation (p. 74). Crucial to the notion of judicial imputation, which applies in both civil and criminal law, is the fact that it includes settling both a question of fact (Thatfrage) and a question of law (Rechtsfrage) (p. 70). Møller thus argues that the transcendental deduction also proceeds in two stages parallel to those of judicial imputation: the first ‘proves that nature is a case falling under the categories because it is synthesized by pure apperception’ while the second step ‘proves that the understanding allows the legitimate application of the categories a priori to “nature in general”’ (p. 78). Of course, the transcendental deduction is not the only deduction in Kant’s Critical philosophy. It would be interesting, for example, to explore whether the two-stage notion of juridical imputation also sheds light on Kant’s arguments regarding moral obligation.

Chapters 5 and 6 offer a solution to ‘Herder’s dilemma’ – roughly the problem of how reason could simultaneously serve as legislator, tribunal and judge in its own case. Here, the threat of circularity looms large. To address this criticism, Møller points to a splitting of the self that occurs, most obviously in Kant’s discussion of conscience (chapter 6). According to the analogy with conscience, the understanding serves as legislator, the power of judgment serves as accuser and reason as judge (p. 136). Kant’s account of conscience is puzzling, and it clearly changes in important respects between the early lectures on moral philosophy (Kaehler/Collins) and the later discussion in the Metaphysics of Morals. Early on, for example, Kant allows for the possibility of an erring conscience; later he does not. Further, in later works, Kant tends to describe conscience not just as a tribunal itself, but also – or perhaps instead – as that which brings the agent to the tribunal in the first instance. Relatedly, Kant thinks of conscience, somewhat curiously, as one of the aesthetic preconditions of virtue in the Doctrine of Virtue (MS, 6: 399–400). Though the analogy with the legal metaphors associated with Kant’s account of conscience nicely illustrates the sense in which reason can participate in its own tribunal via a kind of splitting, the question of what prompts this capacity, or what sets it in motion, still seems mysterious in both cases.

The final chapters of the book further explore Kantian legal metaphors in order to offer an account of Kantian epistemic authority. Of particular interest in this section of the book is Møller’s discussion of different interpretations of judicial authority. Møller argues that Kant tended toward the ‘reformist’ account, according to which the solution to unjust laws is reform, as opposed to an account that allows for judicial interpretation and discretion. Legal verdicts are thus a type of inference that take the form of a syllogism. Taken as an analogy for the judicial authority of reason, this helps to explain how reason can sometimes outstrip its limits (inferences are taken beyond the sphere of experience) and how critical reason can rein in these mistakes (by supplying rules of inference) (p. 128). The volume concludes (chapter 9) with a discussion of systematicity: Møller argues that, although several different metaphors for systematicity emerge in the course of Kant’s Critical philosophy, his legal metaphors for systematicity are the most important, since they ‘demonstrate how a systematic structure can grant validity to judgments’ (p. 169). This final note of Møller’s book captures well the important contribution that it makes throughout: Kant’s legal metaphor is not just jargon; it is a part of the very justificatory argument that supports the critical project as a whole.