Kant and Skepticism, and: Knowledge, Reason, and Taste: Kant’s Response to Hume (review)

In the introduction to the second edition of the Critique of Pure Reason, Kant poses the central question “How is metaphysics, as science, possible?” (B 22). In addressing this question, the critique of reason “necessarily leads to scientific knowledge; while its dogmatic employment, on the other hand, [leads us] to dogmatic assertions to which other assertions, equally specious, can always be opposed—and thus to skepticism” (B 22f.). In Kant’s assessment, skepticism is dangerous since it “makes short work with all metaphysics” (B xxxvi). Hence the task of the critique of reason as a propaedeutics for a future metaphysics must be “to determine, with completeness and certainty, the extent and the limits of its attempted employment beyond the bounds of all experience” (B 23).

The force of skepticism is put to good use as the skeptical method in the service of critical philosophy. However, taken as an end in itself, skepticism cannot provide the “perfect certainty in our knowledge, alike of the objects themselves and of the limits within which all our knowledge of objects is enclosed” (A 761f. / B 789f.). If skepticism merely pursues its own agenda, it “undermines the foundations of all knowledge” (A 424 / B 451).

What is at stake in Kant’s deployment of the skeptical method is a salubrious dislodging of dogmatic frames of reference, which have been taken for granted. It is for this reason that Kant can claim that “[a]ll unsuccessful dogmatic attempts of reason are facts, and it is always of advantage to submit them to censorship of the skeptic” (A 763f. / B 791f.). In itself, the skeptical intervention remains purely negative. The “skeptical procedure,” according to Kant, cannot offer satisfying answers to the questions of reason, but it “prepares the way by arousing reason to circumspection and by indicating the radical measures which are adequate to secure it in its legitimate possessions” (A 769 / B 797).

According to Michael N. Forster, Kant’s relation to skepticism has hitherto not been examined with the necessary care. The lacunae in scholarship that Forster intends to fill concern different versions of skepticism and their roles “in connection with the origination and motivation of the critical philosophy” (3). Forster’s study offers a concise exposition of the importance of skepticism in the development of Kant’s critical philosophy, followed by a critical evaluation of Kant’s position and his success in meeting the skeptical challenge. Forster contends that two of the central aims of the Critique of Pure Reason—namely, to address skepticism and to instigate a thoroughgoing reform of metaphysics—are more closely intertwined than is generally recognized, since Kant’s critical philosophy was primarily a response to those types of skepticism that “threaten metaphysics” (3).

Three varieties of skepticism are addressed in Kant’s work: Cartesian (or Berkeleyan) “veil of perception” skepticism; Humean skepticism; and Pyrrhonian skepticism. In Forster’s reading, the story unfolds as follows: Although in the Anglophone philosophical tradition, the Berkeleyan doubt about the existence of the mind-external world is widely believed to be the paradigm of skepticism, it is the least important in Kant’s argument. To be sure, Kant addresses this type of skepticism in both editions of the first Critique (in the “Fourth Paralogism” of the first edition and the “Refutation of Idealism” in the second edition) and had done so already in his Nova Dilucidatio of 1755. However, in the intervening years and in the Critique itself, this variety of skepticism barely played a role. According to Forster, Kant’s responses to it are mere by-products of his intensive engagement with Humean and Pyrrhonian skepticism.

To Kant’s famous statement in the Prolegomena that “David Hume’s reminder was the very thing which many years ago first interrupted my dogmatic slumber,” Forster juxtaposes another in a letter to Garve from 1798 in which...