The “Transcendental Doctrine of Method” is the second of the two main parts into which Kant's Critique of Pure Reason divides after its introduction. This means that, prima facie, I have an unfair assignment! For my brief is to cover all but one of its four chapters in this chapter, while coverage of the rest of the Critique is accorded ten chapters altogether. In fact, however, this is a misleading way to put it, as anyone remotely familiar with the Critique will know. There is a reason of pure size as to why it is misleading: the second part of the Critique is only one sixth of the length of the whole. But even in a metaphorical sense of magnitude, the second part brooks no real comparison with all that has gone before. It is very common for commentators on the Critique not to pay it any attention at all. Even Norman Kemp Smith, whose 650-page commentary comes as close as any to being a section-by-section companion to the Critique, relegates discussion of this part to a twenty-page appendix and remarks: “[Its] entire teaching . . . has already been more or less exhaustively expounded in the earlier divisions of the Critique.”

“There must somewhere be a source of positive cognitions that belong in the domain of pure reason, and that perhaps give occasion for errors only through misunderstanding, but that in fact constitute the goal of the strenuous effort of reason” (A 795-6/B 823-4). After 800 pages of a book officially dedicated to critiquing reason, and one that seems up to this point to have disparaged reason to the point that its proper role in knowledge appears to be simply to avoid any involvement, Kant seems finally to begin to speak of reason in encouraging terms. In the first page of the Canon of Pure Reason, Kant holds out the hope that the practical use of reason can succeed where the theoretical use of reason has failed - namely, to satisfy “the unquenchable desire to find a firm footing beyond all bounds of experience” (A 796/B 824). The highest aim of reason concerns “what is to be done”, and the ideas of soul, world, and God have their true value in defending the related morally important claims of immortality of the soul, freedom of the will from natural causality, and the existence of God (A 797/B 825f). The practical use of reason, it seems, is the only legitimate use of reason at all. Despite this language, Kant had in fact already provided a legitimate theoretical use of reason 100 pages earlier in the Appendix to the Transcendental Dialectic. The three main ideas of reason - soul, world, and God - cannot refer to any object beyond experience but must be used within experience to order cognitions of the understanding.

Many philosophical advances provide solutions to well-known difficulties. Others arrive instead in the shape of new problems. In the Critique of Pure Reason, Kant adopts the second approach - framing a new question. The Critique aims to revolutionize metaphysics, so demonstrating the salience of a previously overlooked problem was a natural first step. It allowed Kant to present his novel ideas for the system of philosophy as the answer to a compelling challenge: “How are synthetic judgments a priori possible?” (B 19). The job of the “Introduction” to the Critique is to frame this question properly, to articulate the distinctions needed to understand it, and to show its relevance to Kant's larger aims. My exegesis will focus on the second (B) edition version of the “Introduction.” Kant made substantial additions to this chapter in the second edition, but in my view, these alterations mainly aim to bring greater explicitness to points that were already present in the first, so I will trace the argumentative structure in its more fully articulated form. Kant's problem about synthetic a priori judgment must be understood in light of dominant currents in eighteenth-century philosophy, especially the extensive claims on behalf of conceptual truth made by G. W. Leibniz, Christian Wolff, and their followers.

After analyzing our cognitive powers of sensibility and understanding in the first Critique's Transcendental Aesthetic and Transcendental Analytic and arguing that these powers can together yield synthetic a priori knowledge, albeit knowledge limited to objects of appearance, Kant turns to an analysis of the power of reason in the Transcendental Dialectic. Here the outcome is far more negative. Kant identifies many ways in which reason oversteps its bounds, and repeatedly charges the rationalists with such errors. At the same time, he is empathetic toward the rationalists, underscoring that their errors are not obvious or even disingenuous, as the overly simplistic empiricists hold, but instead deep and inevitable, grounded in transcendental confusions that only Kant's transcendental researches can identify if not eradicate. In the first of the Dialectic's three chapters, the “Paralogisms of Reason,” Kant's focus is the rationalists' errors in the field of psychology. The sole purpose for the rationalists' ventures in psychology, Kant repeatedly tells us, is to establish the immortality of the soul. Toward this end, he believes, they need to establish three things about the soul: its permanence, incorruptibility, and personality. So how do they argue for these conclusions? They don't. Instead, Kant thinks they argue for the conclusions of the soul's substantiality, simplicity, and identity. They then simply assume that these conclusions entail permanence, incorruptibility, and personality.

The Critique of Pure Reason has been a constant source of inspiration for philosophers on the European continent for well over a century. In Germany, Kant's theoretical outlook had a noticeable impact even on thinkers struggling to distance themselves from Neo-Kantian thinking. Husserl's controversial recasting of his phenomenological project along transcendental lines inherited from Kant is still evident in Heidegger's early critical revisions of Husserl's method. For Jaspers, “the fate of philosophy hinges on our attitude toward Kant,” more precisely, on our capacity to differentiate the critical method from the uncritical elements of Kant's system. In France, the focus on Kant's theoretical philosophy is no less prevalent, if more critical. Sartre crafts his account of phenomenon, transcendence, selfhood, and others in direct confrontation with Kant's conceptions of them. Similarly, by locating the transcendental conditions of knowledge in the lived body's interaction with its environment, Merleau-Ponty conceives his work as a radical revision of Kant's philosophy. In Kant's Critical Philosophy (“a book about an enemy”), Deleuze attempts to show how a different hierarchical order of faculties dominates each Critique, but - to Kant's credit - without suppressing their differences or neglecting human finitude.

The Critique of Pure Reason by Immanuel Kant (1724-1804) is without question one of the landmarks of the entire history of Western philosophy, comparable in its importance and influence to only a handful of other works such as Plato's Republic, Aristotle's organon of logical works, and Descartes's Meditations on First Philosophy. The Critique was first published in 1781, after a decade of intensive preparation, and within a few years became the center of attention in German philosophy, and shortly after that in other European countries with advanced philosophical culture such as Britain and France as well. In the hope of clarifying some of the obscurity of the work and forestalling its misinterpretation, Kant issued a substantially revised edition of the work in 1787, in spite of his extensive agenda of other philosophical projects. That only intensified the debate about Kant's position, and ever since, students and scholars of Kant's philosophy have had to study the composite work that is the product of those two editions of the Critique. The present Companion is designed to orient readers to the complex structure and arguments of the Critique, to the philosophical context within which it arose, and to the enormous influence it has had and continues to have on the subsequent history of philosophy.

This chapter considers three key works of analytic Kantianism: Clarence Irving Lewis, Mind and the World Order (1929); Sir Peter Strawson, The Bounds of Sense (1966); and Wilfrid Sellars, Science and Metaphysics: Variations on Kantian Themes (1968). We begin with some characteristics of early analytic philosophy that framed analytic philosophers' views of Kant's Critique of Pure Reason. Early Anglophone analytic philosophy came to focus on language. Ordinary language analysis contends that philosophical problems arise from decoupling terms or phrases from their ordinary contexts of use, in which alone they have definite use and meaning; it tends to a therapeutic approach to philosophy. What may be called “ideal language” analysis (broadly speaking) contends that philosophical problems arise through the use of the “material” mode of speech - that is, ordinary speech about persons, things, or events, to formulate philosophical problems; diagnosing and solving or dissolving these problems requires ascending to a constructed “formal” mode of speech, which restates those issues concerning sentences or statements. Though such philosophy can be therapeutic, most versions tended to more ambitious, constructive philosophical analyses.

The Critique of Pure Reason sets out to establish the sources, extent, and limits of a priori knowledge, with a view to ascertaining the prospects for metaphysics as a scientific enterprise. Kant defines a priori knowledge as knowledge that is “absolutely independent of all experience,” and distinguishes it from empirical knowledge, whose sources lie in experience (B 2-3). The Critique's second edition frames its overarching goal as a general solution to the problem: How are synthetic judgments a priori possible? (B 19) This formulation, intended to express the work's focus on the problem of non-trivial a priori knowledge of objects, presupposes two important doctrines. Kant holds that the knowledge constituting the proper end of metaphysics is never mere empirical knowledge, even when the object of investigation is empirical reality. He also insists that substantive knowledge of objects does not find expression in merely analytic judgments - those in which the predicate “does not add anything” to the subject concept, but merely “breaks up” this subject concept into components “already thought in it” (A 6-7/B 10-11). The Critique's epistemological investigation aims to “assure to reason its lawful claims, and dismiss all groundless pretensions, not by despotic decrees, but in accordance with reason's own eternal and unalterable laws” (A xi-xii). Kant employs “reason” in such contexts, in contrast to a narrower sense later introduced, as a general label for cognitive capacities underwriting a priori knowledge (A 11/B 24; A 305/B 363; A 323/B 380).

The “System of all principles of pure understanding” is the second of three chapters in the Analytic of Principles. It is preceded by the Schematism chapter, in which Kant provides schemata, or time-determinations (in effect, spatio-temporal meanings), for the pure concepts of the understanding such that they can then be applied to objects given in sensible intuition. It is followed by the Phenomena/Noumena chapter, which summarizes the restrictions on cognition that Kant has established so far, and draws out some consequences thereof, especially insofar as they make clear the mistakes of earlier philosophers such as Leibniz and Locke. Despite the clear significance of these chapters, however, it is the System that forms the core of Kant's Analytic of Principles. For it contains his most detailed and specific positive account of how the categories - whose existence and legitimacy were established in a merely global way in the Metaphysical and Transcendental Deductions - are to be applied to appearances - that is, to objects given to us in sensible intuition. It does so not only by arguing for particular conditions under which each category must be applied, but also by providing insight into what Kant thinks any spatio-temporally unified world of experience must be for us - namely, a plurality of substances that stand in causal relations of mutual interaction, a view that is radically different from Hume's empiricism, though it has important parallels with the views of several of his predecessors, such as Wolff, Crusius, and Tetens.

The beginning of the Transcendental Dialectic marks an important transition in the Critique of Pure Reason and in Kant's philosophical system as a whole. In approximately the first half of the Critique, Kant argues that we can have immanent metaphysical knowledge of synthetic a priori principles that structure all possible human experience, because they are grounded in our pure forms of intuition (space and time) and the pure concepts of our understanding (the categories). But Kant's argument for this immanent metaphysics rests on his claim that human knowledge can result only from applying concepts to intuitions, or more precisely to schemata mediating the application of concepts to appearances. This key claim implies that transcendent metaphysical knowledge - knowledge of objects that transcend the boundaries of possible human experience - is impossible for us, since it would involve deploying concepts independently of intuitions or schemata. If Kant had ended the Critique at this point, then his positive argument for an immanent metaphysics in the first half of the book would be wide open to attack from those unwilling to accept its strong negative implication that transcendent metaphysics is impossible. But as Kant was well aware, the Leibniz-Wolffian tradition that dominated German philosophy in the eighteenth century held that transcendent metaphysics is not only possible but actual.

In the Preface to the first edition of Critique of Pure Reason in 1781, Kant wrote that he was “acquainted with no other investigations more important for getting to the bottom of that faculty we call the understanding, and at the same time for the determination of the rules and boundaries of its use, than those I have undertaken in the second chapter of the Transcendental Analytic, under the title Deduction of the Pure Concepts of the Understanding; they are also the investigations that have cost me the most, but I hope not unrewarded, effort” (A xvi). In 1786, in the Preface to the Metaphysical Foundations of Natural Science, Kant lamented that this deduction, “the very part of the Critique that ought to be precisely the most clear,” had instead been found “rather the most obscure,” even circular (MANW, 4:476), and for the second edition of the Critique, a year later, Kant rewrote this chapter completely, hoping to remove its “obscurity” while maintaining that he had “found nothing to alter either in the propositions” of the whole work “or in their grounds of proof” (B xxxvii-xxxviii).

The Second Chapter of Book Two of the Transcendental Dialectic, which deals with the pretensions of rational cosmology, contains one of the most ambitious discussions in the Critique of Pure Reason. Its argument is as far-ranging and complex as any in the entire Critique (even that of the Transcendental Deduction of the Categories). One aim is to show that any pure rational doctrine of the world's constitution is led inevitably, through a system of cosmological ideas or pure concepts of reason, into contradictions, based not on the contingent errors of any individual metaphysician but on reason's own necessary principles and procedures. A second aim is to discredit, more specifically, the pseudo-science of rational cosmology that was part of Wolffian metaphysics, by showing that if its claims to cognition were valid, they would drive reason into contradiction with itself. A third aim is to establish the central claims of the critical philosophy, especially transcendental idealism, as essential to the resolution of the antinomies. Yet a fourth aim is to understand each of the issues that give rise to the antinomies individually, resolving the problem from which it arose. Finally, Kant claims that the antinomies concern not only theoretical philosophy but also the practical interests of reason.

When Kant surveyed what the history of metaphysics had left behind, he saw a “stage of conflict” - a disconsolate landscape of edifices fallen into ruins (A 852-3/B 880-1). Most of the wreckage, when new, had been the proud work of the philosophers Kant called “dogmatists.” Kant never wavered in his admiration for their highest standards of construction: “the regular ascertainment of . . . principles, the clear determination of . . . concepts, the attempt at strictness in . . . proofs, and the prevention of audacious leaps in inference” (B xxxvi). The failure of the dogmatists lay not in their manner of building, he thought, but in their decision to begin construction on what turned out to be uncertain ground. They had neglected, he explained, to “prepare the field” (B xxxvi) - to conduct a “critique” or assessment of their own capacities. The failure of the dogmatists was, in Kant's view, a failure of self-examination. Socrates had long before insisted that the unexamined life is not worth living, but philosophical projects commencing with self-examination were especially characteristic of modernity. Descartes's Meditations is probably the best-known example.

Kant's Critique of Pure Reason is divided into two sections, the “Transcendental Doctrine of Elements” and the “Transcendental Doctrine of Method”, the former of which is further divided into two parts, the “Transcendental Aesthetic” and the “Transcendental Logic.” Although it is comparatively very short, the Transcendental Aesthetic is a crucially important component of Kant's work, its stated aim being to present a “science of all principles of a priori sensibility” (A 21/B 35). Here, Kant articulates a theory of pure sensible intuition, and deploys arguments in support of the transcendental ideality of space and time. Taken together, the Transcendental Aesthetic and the Transcendental Logic (“which contains the principles of pure thinking”) are meant to provide an account of human cognition and judgment according to which sensibility and understanding - our capacities for being affected by and for thinking about objects, respectively - each play ineliminable roles. In what follows, I will identify and explain the terminology that Kant introduces in the Aesthetic; present and discuss the arguments Kant offers in the Metaphysical and Transcendental Expositions of Space and Time; and show how (and why) Kant concludes from these “expositions” that space and time are transcendentally ideal.