Kant

Paul Guyer

• Publisher: Routledge
• Year: 2014
• ISBN:
  9781135015626
• Edition: 2
• Topic: Philosophie
• Subtopic: Histoire et théorie de la philosophie

In this updated edition of his outstanding introduction to Kant, Paul Guyer uses Kant's central conception of autonomy as the key to his thought.

Beginning with a helpful overview of Kant's life and times, Guyer introduces Kant's metaphysics and epistemology, carefully explaining his arguments about the nature of space, time and experience in his most influential but difficult work, The Critique of Pure Reason. He offers an explanation and critique of Kant's famous theory of transcendental idealism and shows how much of Kant's philosophy is independent of this controversial doctrine.

He then examines Kant's moral philosophy, his celebrated 'categorical imperative' and his theories of duty, freedom of will and political rights. This section of the work has been substantially revised to clarify the relation between Kant's conceptions of "internal" and "external" freedom. In his treatments of Kant's aesthetics and teleology, Guyer focuses on their relation to human freedom and happiness. Finally, he considers Kant's view that the development of human autonomy is the only goal that we can conceive for both natural and human history.

Including a chronology, glossary, chapter summaries and up-to-date further reading, Kant, second edition is an ideal introduction to this demanding yet pivotal figure in the history of philosophy, and essential reading for all students of philosophy.

Part One

Nature

Two

Kant’s Copernican revolution

This chapter and the next will consider the central themes of Kant’s theoretical philosophy as presented in the Critique of Pure Reason: this long chapter will discuss Kant’s positive view of the elements and limits of human knowledge, and the next, shorter chapter will discuss the criticism of the pretensions of traditional metaphysics that Kant makes on the basis of his own positive view. After first explaining how Kant conceives of the basic problem for theoretical philosophy as a problem about the possibility of “synthetic a priori judgment,” I will then review the series of steps he takes in the Critique in order to demonstrate that such cognition is indeed possible.

Introduction

In the Preface to the second edition of the Critique of Pure Reason, Kant writes that the “general” and “real problem of pure reason is … contained in the question: How are synthetic judgments a priori possible?” (B 19). Kant would henceforth formulate the deepest questions of philosophy, such as the questions about the unconditional authority of the moral law and even about the universal validity of judgments of taste, as questions about the possibility of synthetic a priori judgments (see G, 4:444–5, and CPJ, §36, 5:288). So the first question about Kant’s mature philosophy is: what is a synthetic a priori judgment?

Kant arrives at his conception of synthetic a priori judgment by giving new names to two old distinctions, and then combining them. First, he distinguishes “cognitions a priori … from empirical ones, which have their sources a posteriori, namely in experience” (B 2). Earlier philosophers had used the terms a priori and a posteriori to designate different kinds of inferences or arguments: those from causes to effects and those from effects back to causes, respectively;¹ but Kant uses these two terms to characterize different kinds of knowledge.² Empirical, a posteriori cognitions are simply those that are based on the experience of particular objects – for example, my knowledge that the copy of the Critique of Pure Reason from which I have just quoted is bound in blue cloth is empirical and a posteriori because it is based on my visual perception of the book today and many previous times. A priori cognitions, conversely, are those that are not based on any experience of particular objects, even though they may – indeed, as Kant ultimately argues, must – apply only to such objects. A posteriori knowledge is always knowledge of something contingent for Kant,³ who accepts the position earlier argued by Hume that “Experience teaches us, to be sure, that something is constituted thus and so, but not that it could not be otherwise” (B 3). Experience tells us only that those objects that have actually been observed are a certain way, not that all objects, even of some particular kind, must be that way. By contrast, if we are ever in a position to claim that all objects of some kind must be some particular way, that is, to make judgments that claim “necessity” and “true or strict … universality,” then our knowledge cannot be a posteriori, but must be a priori – we must somehow make our judgment independently of appeal to any particular experiences.⁴ “Necessity and strict universality are therefore secure indications of an a priori cognition” (B 4).

Next, “analytic” and “synthetic” are Kant’s terms for two kinds of judgments, or in more contemporary terms, propositions that are the contents of acts of judgment, thus of belief or knowledge. An analytic judgment is one in which “the predicate B belongs to the subject A as something that is (covertly) contained in this concept A,” and which is therefore thought to be true “through identity” (A 6–7 / B 10). In other words, where the meaning of a concept A is actually constituted by a conjunction of predicates including B, for example BC, the proposition “A is B” is true because it is really equivalent to “BC is B,” and this is true because “B is B” is always true; for example, the proposition “All bachelors are unmarried” is true just because “bachelor” means “unmarried male,” and the proposition “All unmarried males are unmarried” is true “through identity.”⁵ In our terms, then, analytic propositions are those that are true simply in virtue of the meanings of their terms and the laws of logic.⁶ Synthetic propositions, conversely, are those in which the predicate “B lies entirely outside the concept A, although to be sure it stands in connection with it” (A 6 / B 10); thus, true synthetic propositions are those that are true in spite of the fact that the predicate is not contained in the concept of the subject, and must therefore be made true by something other than the meanings of the terms involved and the laws of logic. Kant states that analytic judgments can also be called “judgments of clarification,” for they simply clarify what is already implicit in our concepts, while synthetic judgments can be called “judgments of amplification,” because – when they are true, of course – they genuinely add information to what is already contained in our concept of their subjects (A 7 / B 11).

What happens when we combine these two distinctions? Well, analytic judgments clearly can and must be known a priori: once we understand the meaning of the terms “bachelor,” “male,” and “unmarried” and know the laws of logic (although learning the meaning of concepts, to be sure, may itself be a matter of experience, for Kant, learning the laws of logic cannot be), we can know that all bachelors are unmarried by applying the laws of logic to the meaning of “bachelor” without making empirical observations of any bachelors. Indeed, we can only know that all bachelors are unmarried by such an inference from the meaning of the terms, since any amount of observation could only teach us that some bachelors – namely, those we have observed – are unmarried. In fact, we can only classify an observed male as a bachelor in the first place if we already know him to be unmarried – that’s what it means for “unmarried” to be part of the meaning of “bachelor.” Equally clear, many synthetic propositions can only be known a posteriori, that is, from observation or experience: I can only know that my copy of the Critique of Pure Reason is blue by observing it, because the predicate “blue” is certainly not contained in the concept book, or the concept of the Critique of Pure Reason, or of an English translation of the Critique – different editions and translations of the Critique have come in many different colors. So there are analytic a priori cognitions – that is, analytic propositions known a priori – and synthetic a posteriori cognitions. Is that all? An earlier philosopher such as Hume had thought so: in his terms, “All the objects of human reason or enquiry may naturally be divided into two kinds, to wit, Relations of Ideas” – that is, analytic and therefore a priori cognition – “and Matters of Fact” – that is, particular synthetic propositions known a posteriori.⁷ But in Kant’s view, while there cannot be such a thing as an analytic proposition known a posteriori (even though some of the concepts in such propositions may be empirical), there not only can be but are synthetic a priori cognitions. Indeed, for Kant, all the fundamental propositions of philosophy as well as the contents of pure mathematics and even the basic principles of natural science are nothing less than synthetic a priori cognitions,⁸ and the project of the Critique of Pure Reason is precisely to convince us that Hume was wrong to disallow synthetic a priori principles in philosophy – although of course Hume had not expressed his doubts about philosophical principles in these terms – and thus to refute Humean skepticism about first principles, the position that even the most fundamental principles of our knowledge, such as that every event has a cause, are based on experience, and therefore never have real necessity and true or strict universality, but are contingent propositions with at best “assumed and comparative” universality (B 3).⁹

Now it must be noted at the outset that Kant creates some confusion about just what questions about synthetic a priori cognition his philosophy is intended to answer. In the Prolegomena and in some passages carried over from that work into the revised introduction of the second edition of the Critique of Pure Reason, Kant makes it seem as if everyone already knows that there is such a thing as synthetic a priori cognition – in pure mathematics and pure physical science – and that the task of philosophy is just, first, to explain how such actual cognition is possible, and then, second, to demonstrate from that explanation that there are some further synthetic a priori cognitions in metaphysics itself (Prolegomena, §§2–4, 4:268–75; Pure Reason, B 14–22). This is why Kant says that the method of the Prolegomena is analytic – here now using the term in its traditional sense of a regress from effects back to their causes rather than in his own new sense – for it relies “on something already known to be dependable, from which we can go forward with confidence and ascend to the sources, which are not yet known, and whose discovery not only will explain what is known already” – that is, pure mathematics and physics – “but will also exhibit an area with many cognitions that all arise from these same sources” (4:275) – that is, whatever is legitimately known in metaphysics.

Of course, if one doubts that mathematics and physics do contain synthetic a priori cognition, then the use of this analytic or regressive method to arrive at further metaphysical truths is in trouble from the outset. But in the Prolegomena, Kant says that “In the Critique of Pure Reason I worked on this question synthetically, namely by inquiring within pure reason itself, and seeking to determine within this source both the elements and the laws of its pure use, according to principles” (4:274). This statement is gnomic, but seems to suggest that at least in the first edition of the Critique, thus in his original conception of it, Kant did not intend to presuppose that we have any synthetic a priori cognition, in mathematics or in metaphysics, but instead meant somehow to identify some indisputably basic elements of any cognition and then to show from those results that we in fact have synthetic a priori cognition not only in metaphysics but in pure mathematics and physical science as well. As he put it in the Preface to the first edition of the Critique, talking about his central “Deduction of the Pure Concepts of the Understanding,” his objective is both “to demonstrate and make comprehensible the objective validity of its concepts a priori” (A xvi), that is, to both prove that we have synthetic a priori cognition in mathematics, science, and metaphysics and then explain how such knowledge is possible. Throughout what follows, I will understand Kant to have this twofold aim in the central arguments of the Critique of Pure Reason.¹⁰

So how can Kant show that the first principles of mathematics, science, and philosophy itself are synthetic propositions known a priori, not merely a posteriori – that is, how can he refute Humean skepticism that what may seem to us to be universal and necessary principles are in fact nothing but contingent and incomplete generalizations – without flying off into ungrounded metaphysics? Kant’s proposal is to try a procedure analogous to the “first thoughts of Copernicus” (B xvi) – what has come to be known as his “Copernican revolution” in philosophy. Just as Copernicus,

when he did not make good progress in the explanation of the celestial motions if he assumed that the entire celestial host revolves around the observer, tried to see if he might not have greater success if he made the observer revolve and left the stars at rest,

so

in metaphysics we can try in a similar way regarding the intuition of objects. If intuition has to conform to the constitution of the objects, then I do not see how we can know anything of them a priori; but if the object (as an object of the senses) has to conform to the constitution of our faculty of intuition, then I can very well represent this possibility to myself. Yet because I cannot stop with these intuitions, if they are to become cognitions, but must refer them as representations to something as their object and determine this object through them, I can assume that the concepts through which I bring about this determination also conform to the objects, and then I am once again in the same difficulty about how I could know anything about them a priori, or else I assume that the objects, or what is the same thing, the experience in which alone they can be cognized (as given objects) conforms to those concepts, in which case I immediately see an easier way out of the difficulty.

(B xvii)

In other words, Kant argues, if we assume that the basic forms of our intuitions and concepts of objects, that is, of their sensory representations and conceptual organization, are derived from our experience of given objects, then our knowledge of them will never be more than a posteriori, thus contingent and limited, but if we can discover fundamental forms for the sensory representation and conceptual organization of objects within the structure of our own minds, then we can also know that nothing can ever become an object of knowledge for us except by means of these forms, and thus that these forms necessarily and universally apply to the objects of our knowledge – that is, that they are synthetic a priori.

Now, at first glance, Kant’s proposal seems to be the exact opposite of Copernicus’s procedure. Copernicus thought that Ptolemaic astronomy was a mathematical mess because it assumed that everything revolves around us here on earth, and introduced its mathematical simplification by demoting the significance of our own position as observers, positioning us on what is merely one more body rotating around the sun.¹¹ Kant, however, glorifies our significance as observers, holding that all objects must conform to the conditions of our experience rather than the conditions of our experience conforming to the independent character of the objects. The analogy seems to be only that in philosophy, as in astronomy, progress sometimes requires a radical reversal of traditional assumptions. Of course, should Kant’s revolution in philosophy prove as enduring as Copernicus’s revolution in astronomy, we wouldn’t mind this confusion!¹²

The Copernican revolution in philosophy, that is, the assumption that we can find fundamental conditions of the possibility of our own experience to which the objects of our experience must conform, is the basis for Kant’s first claim of autonomy, the claim that sensibility and understanding, as two main faculties of the mind, contain “the constitutive principles a priori for the faculty of cognition (the theoretical cognition of nature” (CPJ, 5:196)). But just how strongly does Kant mean this claim of autonomy to be taken? Very strongly, it turns out: what Kant will argue throughout the Critique of Pure Reason is not just that objects must conform to the conditions of our cognition of them if we are to have success in coming to know them, but that we can actually impose such conformity to the conditions of our cognition upon them – that “as exaggerated and contradictory as it may sound to say that the understanding is itself the source of the laws of nature … such an assertion is nevertheless correct and appropriate to the object, namely experience” (A 127; emphasis added). But, as Kant had made clear since his famous letter to Marcus Herz, he does not suppose that we are actually gods or demiurges who literally create the objects of our experience. Instead, what he will argue is that we can and must impose conformity to the conditions of the possibility of our own experience on the way that objects appear to us, but precisely for that reason how objects may be in themselves is bound to remain unknown to us. In other words, Kant’s refutation of Humean skepticism, that is, his proof and explanation of the existence of synthetic a priori cognitions by appeal to the very conditions of the possibility of our own experience, seems to drive him into something like Cartesian skepticism, the denial that our way of representing things has any necessary resemblance to the way things are in themselves.

Here Kant seems to go well beyond his analogy with Copernicus. It is true that on the Copernican model of the solar system, our observations of the motions of the planets are downgraded to merely apparent motions: the apparent progressions and retrogressions that were earlier thought to be genuine epicycles on the planetary orbits are now explained away as nothing more than the way the motions of other planets revolving around the sun appear to an observer whose own planet is also revolving around that body. But this explanation convinces precisely because it can derive the apparent motions of the planets from a substantive and ultimately well-grounded hypothesis about the real motions of the planets around the sun. On Kant’s theory, however, we are supposed to downgrade our experience of objects to mere appearance without knowing anything about the real character of those objects at all. What leads Kant to such a radical position, and do we have any reason to follow him there?¹³

We now have two great questions to ask about Kant’s theory ...