This chapter draws on Kant’s key term, “critique”, and its relation to Kant’s central concern with the possibility of knowledge and the status of metaphysics in order to present the basic character, the overall orientation and the general strategy of Kant’s mature work in theoretical philosophy. In line with the introductory intent of the chapter, Kant’s train of thoughts is not presented in its intricate details and technical terminology but in the form of a broadly conceived argumentative reconstruction of Kant’s project that seeks to avoid partisan interpretations and is intentionally kept free of scholarly discussions, interpretive controversies and exegetical minutiae.
The primary texts underlying the portrayal of Kant’s critical stand on knowledge and metaphysics are the prefaces and introductions of the first and second editions of the Critique of Pure Reason (CpR A vii-xxii and 1–16; CpR B vii-xliv and 1–30) along with §14 of the first Critique (contained in both editions of the work but so numbered only in the second one; CpR A 92–4; CpR B 124–9) and the introduction along with §§57–60, entitled “On the Determination of the Boundary of Pure Reason”, of the Prolegomena to Any Future Metaphysics (4:350–65), a popularly cast companion piece that Kant published between the first and the second edition of the Critique of Pure Reason. For the Prolegomena, refer to Kant (2004a).
Critique and reason
The term “critique” can serve to designate and characterize Kant’s entire mature philosophy, which was propagated by him and his followers as “critical philosophy” after it had initially been presented by Kant in three works bearing the term “critique” in their very title:Critique of Pure Reason (1781; second, in part revised, edition 1787), Critique of Practical Reason (1788) and Critique of the Power of Judgment (1790). Yet Kant did not set out to write a set of three critiques. Neither did he plan the second Critique when writing the first one, nor the third Critique when writing the second one. Rather, the critical trilogy grew out of the initial critical project, as contained in the Critique of Pure Reason, by extending the primary enquiry into the theoretical-cognitive potential of reason first into the investigation of reason’s practical-volitional potential and finally into the survey of the potential of the power of judgement to reflect on the purposive organization of things in nature and culture. Hence “critique” in Kant refers to addressing and solving philosophical problems in a manner that was first methodically developed and carried out in the Critique of Pure Reason and subsequently taken over into further fields of philosophical investigation.
In the preface to the first edition of the Critique of Pure Reason Kant refers to the broader contemporary context for his critical project by calling his own times “the age proper of critique” (CpR A xi n), referring to the Enlightenment project of questioning traditional authority and replacing justification and validation by appeal to established and cherished beliefs with achieving insights through the use of one’s own powers of reasoning. In Kant’s adaptation of the term “critique” to his own work in philosophy the word retains the general meaning of a detection of prejudice and error in received views but also assumes the more specific sense of a principled assessment of the extent to which claims in general, or claims of a specific kind, may be justified or justifiable. Most importantly, Kant throughout ties the term “critique” to the revisionary assessment of the claims of reason or of the claims made by or on behalf of reason, as opposed to claims based on experience or other claimed sources of insight.
In Kant’s usage, “reason” designates at the most general level the higher mental powers in their entirety, as opposed to the lower mental powers based on the senses. To critically assess reason therefore means to enquire into reason’s ability to provide insights that are not based on the senses, or at least not only based on the senses, but that rely specifically, if not exclusively, on the resources of reason or on the powers of thinking and conceiving, as opposed to those of sensing and perceiving.
The particularly close connection between “critique” and “reason” in Kant, manifest chiefly in phrases such as “critique of reason”, “critique of pure reason” or “critique of pure speculative reason”, typically takes the grammatical form of a genitive construction in which reason is at once the object that is being criticized and the subject that is undertaking the critique. With no other, external, authority suited to judging and adjudicating the claims of reason, which exceed, in principle, the scope of experience and thus are open only to non-empirical, strictly argumentative forms of validation, reason itself must undertake the business of critique. Hence the critique of reason is, in essence, the self-critique of reason. To be sure, reason cannot be the subject and agent of its own critique in the literal sense of carrying it out, as it were, in person. After all, reason, on Kant’s understanding, is not some magical supra-human mind or spirit but the sum total of the principles regulating thinking in beings like us, finite rational beings, that possess the ability or, in Kant’s preferred term, the “faculty” [Vermögen]
to think. For Kant to undertake the self-critique of reason means to engage in an examination of reason by means of reason in order to assess, in a principled manner, what reason is capable of – and what not.
Critique and knowledge
On Kant’s view, reason is not easily capable of a radical self-examination of the extent of its potential. For the most part, reason, or rather the human being in his or her use of reason, misjudges its abilities and lets itself be misled into illusions about the extent of its powers. That reason is entrusted with its self-critique reflects not its past or present actual performance but its future, possible accomplishment in Kant’s assessment. Moreover, for Kant the critique of reason is not only a possible enterprise to be undertaken at one’s discretion but a requirement in order to settle, once and for all, the factual dispute about the claims of reason.
The claims of reason under critical scrutiny in Kant are, in the first instance, reason’s cognitive claims or claims to cognition to be achieved by means of reason. Kant uses the term “cognition” [Erkenntnis]
to cover knowledge claims of all kinds and any possible extent, regardless of whether they turn out, upon closer inspection, to be justified or unjustified. Typically, though, the cognitive claims of reason are maintained in the stronger sense of asserting the cognition in question to be justified and true. Kant designates the cognitions claimed and proven to possess justification and truth as “knowledge” [Wissen], a
term closely connected in German with the word for scientific knowledge or science [Wissenschaft
In light of the epistemological distinction between asserted or claimed cognition, that is, mere cognition, and validated or warranted cognition, that is, knowledge, the task of a critique of reason can be described as the sorting of the cognitive claims of reason according to whether or not they pass the test for warranted assertibility as well as truth and can be considered knowledge. Kant himself highlights the justificatory dimension of the critique of reason by drawing extensively on the imagery and conceptuality of jurisdiction and casting the critique of reason as a contested case before a court of law.
Kant distinguishes several kinds of cognitions or cognitive claims. In the Critique of Pure Reason and its associated works, especially the Prolegomena to Any Future Metaphysics (1783), the focus is on cognitions regarding what is, or is purported to be, the case. Cognitions of this kind, as well as the corresponding knowledge in case of possible or actual epistemic justification, are termed “theoretical”. By contrast, the Critique of Practical Reason and the associated work in foundational moral philosophy, the Groundwork of the Metaphysics of Morals (1785), focus on cognitions regarding what ought to be the case, or is so claimed. Interestingly, Kant avoids applying the term “knowledge” [Wissen] to sufficiently justified practical cognitions, effectively limiting the use of the term “knowledge” to the sphere of theoretical cognition and its critical examination in theoretical philosophy. To be sure, this terminological practice in Kant does not imply a lack of possible justification for certain claims to practical cognition, in particular those practical claims regarding the very principle of morality (the categorical imperative) and its various formulations and variant specifications.
A main reason behind Kant’s asymmetrical treatment of the distinction between cognition and knowledge with respect to the spheres of the theoretical and the practical may be the close association of the concept of knowledge with the cognitive orientation towards objects, either particular objects (individuals) or classes of such objects (kinds). While theoretical cognitions and the corresponding knowledge serve to determine the object by ascertaining the latter’s existence and properties, practical cognitions function by determining the will, with an eye towards realizing something that is not yet the case. On Kant’s understanding, theoretical cognition as well as (theoretical) knowledge, as opposed to practical cognition, involve a determining reference to an object or to objects, or, in short, objective reference.
In the Critique of Pure Reason
Kant’s chief concern is with assessing the objective reference of cognitions and specifically with accounting
for certain cognitions with claims to objective reference being justified and true and hence instances of knowledge. Given the philosophical nature of Kant’s interest in the objective reference of cognitions, his investigation does not target the contingent circumstances under which such objectively valid cognition, or knowledge, might be given, but the conditions that are in principle necessary for such cognition, or for knowledge, to obtain. In Kant’s parlance, his enquiry concerns the “conditions of the possibility” of objectively valid cognition or of knowledge. On Kant’s understanding, the necessary conditions of knowledge do not involve contingent psychological features pertaining to the mental make-up of beings like us, who are capable of theoretical cognition. Rather they involve the necessary structural conditions for the objective validity of cognitive claims, which alone are the conditions that allow us to distinguish between beliefs about objects that we may happen to hold, for whatever reason (including adherence to authority, prejudice and illusion), and warranted cognitive claims about objects that are justifiably true.
Knowledge and metaphysics
Considering the normative intent of Kant’s assessment of cognitive claims in the Critique of Pure Reason, the critical project might be considered a work in the theory of knowledge or epistemology, even though the latter term, or rather its German equivalent [Erkenntnistheorie], is not to be found in Kant himself but rather has been coined and used under the influence of Kant’s critical philosophy beginning in the nineteenth century in order to distinguish the psychology of cognition from the epistemic logic of knowledge. Yet the Critique of Pure Reason is not an epistemology in the more recent sense of a general theory of knowledge, as opposed to, say, a theory of scientific knowledge investigated in the philosophy of science. Kant’s critical epistemology is primarily targeted at knowledge of a special kind, or rather at a special kind of cognitive claims that are to be examined with regard to their possible qualification as knowledge. Only secondarily and as a by-product of that primary investigation does the Critique of Pure Reason address other or more general cognitive claims.
The special kind of cognition (and possible knowledge) that the Critique of Pure Reason
has in view is knowledge regarding super-sensory objects, or objects that, by definition, elude verification or falsification by appeal to objects given by the senses. Kant has strong reasons for choosing the special focus of the Critique of Pure Reason
on the epistemology of metaphysical knowledge. Historically, and well into Kant’s own time, metaphysics was considered the core area of philosophical study or, in the words of Aristotle, “first philosophy” (Greek, prote philosophia
; Latin, prima philosophia)
. In medieval times Aristotelian metaphysics had been incorporated into Christian theological thinking, resulting in a doctrinal system of school philosophy or scholasticism (from the Latin word for “school”, schola)
Even the early modern period, marked by the triple renewal of humanism in literature, renaissance in the arts and reformation in religion and theology, to a large extent retained the ambition of academic philosophy as a system of doctrinal metaphysics in which the nature of God, the world and the human beings in it was to be ascertained and proven by means of reason alone. In the German lands (there was no politically unified Germany at the time, Kant himself being a citizen of the fairly recently established kingdom of Prussia) the reigning school of philosophy had been built on the foundations of the metaphysical system of Gottfried Wilhelm Leibniz (1646–1716) by Christian Wolff (1679–1754) and his students, chiefly among them Alexander Gottlieb Baumgarten (1714–62). The Wolffians had divided metaphysics into general metaphysics (metaphysica generalis), which they identified with the study of being as such or the investigation of the general kinds and features of being (ontologia), and special metaphysics (metaphysica specialis) or the study of three special object domains of being, namely, God, the human soul and the world in its entire...