Kant's Reform of Metaphysics: The Critique of Pure Reason Reconsidered by Karin de Boer (review)

Looking back at the reception of Kant's philosophy in the twentieth century, it is striking to see how many philosophers tried to enlist Kant in their campaigns to "overcome" and "eliminate" metaphysics. Twentieth-century Kant scholars often shared their contemporaries' hostility to metaphysics, especially the "dogmatic" rationalism of Leibniz and Wolff. These attitudes can still be found within the discipline and among Kant scholars, but much has changed in the last thirty years. Metaphysics has been revived as a central part of both analytic and continental philosophy. And historical, contextualist Kant scholarship has established that there are important continuities between Kant and his rationalist predecessors. Metaphysics may not be "the queen of all the sciences," but it is no longer "despised on all sides" or "outcast and forsaken" (Aviii).

Karin de Boer pushes the rehabilitation of metaphysics in contemporary Kant scholarship even farther in her excellent new book, Kant's Reform of Metaphysics. De Boer rejects claims that the Critique of Pure Reason is an attempt to ground Newtonian physics or to identify the conditions of possible experience (7–9). Nor does she think Kant wanted to constrain metaphysics within "the bounds of sense" (259) or to impose some kind of epistemic modesty on his rationalist predecessors (255–56). In fact, de Boer maintains that Kant intended to reform the rationalist metaphysics of Leibniz, Wolff, and Baumgarten in his first Critique. Even the structure of Kant's system of pure reason is to be understood as an "overhaul" of Baumgarten's metaphysics on de Boer's interpretation (222–30). The image of Kant's system that emerges from her reconsideration of the first Critique is dramatic and compelling.

De Boer makes the case for her metaphysical reconsideration of the first Critique in eight chapters. Chapters 1 and 2 deal with the background and context of Kant's reform of metaphysics, describing his assessments of Wolff's system and Crusius's objections to Wolffian rationalism, as well as the relation between Kant's critique of pure reason and the science of metaphysics that it was meant to promote. Chapters 3 and 4 address the contributions the first Critique makes to ontology, understood as "general metaphysics," by examining the relation between ontology, metaphysics, and transcendental philosophy, as well as the status of things in themselves, noumena, and transcendental objects within Kant's ontology. Chapters 5, 6, and 7 focus on the first (A, 1781) version of the Transcendental Deduction, the Schematism chapter of the Analytic of Principles, and the Appendix to the Transcendental Analytic on the Amphiboly of the Concepts of Reflection. In chapter 8, De Boer jumps ahead to the chapter on the Architectonic of Pure Reason in the Doctrine of Method, in order to describe the structure of the system of pure reason that Kant envisions, including his reform of "special metaphysics"—what was, for Baumgarten, rational psychology, rational cosmology, and rational theology. Chapter 8 is followed by a brief conclusion in which de Boer summarizes her interpretation of the Critique of Pure Reason.

Throughout Kant's Reform of Metaphysics, de Boer takes Kant's conception of metaphysics in the first Critique to be consistent with his inaugural dissertation from 1770, On the Form and Principles of the Sensible and the Intelligible World. In the inaugural dissertation, Kant defines metaphysics as "the philosophy which contains the first principles of the use of the pure understanding" (Ak 2:395, §8). This leads de Boer to attribute to Kant the view that metaphysics is a "purely intellectual" discipline (19, 45, 61, etc.) that excludes everything sensible and empirical, since the intellect (the Latin intellectus) is equivalent to the faculties of understanding (the German Verstand) and reason (the German Vernunft). According to de Boer, Kant's critique is meant to disentangle purely intellectual concepts from sensibility and experience, while also defending the possibility of a science of metaphysics as a system of pure...