Kant’s Copernican revolution

Kant’s Copernican revolution
Kant’s Copernican revolution Daniel Bonevac Immanuel Kant’s Critique of Pure Reason was to transform the philosophical world, at once bringing the Enlightenment to its highest intellectual development and establishing a new set of problems that would dominate philosophy in the nineteenth century and beyond. As Richard Rorty has observed, Kant would turn philosophy into a profession, if for no other reason than that, after 1781, one could not be called a philosopher without having mastered Kant’s first Critique—which, in the words of Kant’s famous commentator, Norman Kemp Smith, “is more obscure and difficult than even a metaphysical treatise has any right to be.”1 The Critique’s central character is “Human reason,” which, Kant begins his first edition’s preface by noting, has this peculiar fate that in one species of its knowledge it is burdened by questions which, as prescribed by the very nature of reason itself, it is not able to ignore, but which, as transcending all its powers, it is also not able to answer. (A vii)2 Reason develops principles to deal with experience; within the realm of experience, those principles are well justified. Reason finds itself driven, however, to ask questions extending beyond that realm. The very principles it has developed and upon which it properly continues to rely in dealing with experience there lead it “into darkness and contradictions” (A viii). Metaphysics, once Queen of the Sciences, now surveys the battlefield on which these principles clash and mourns. Kant’s aim in the Critique is to rescue metaphysics, “to secure for human reason complete satisfaction” (A 856, B 884) by defining its proper sphere of application. Kant’s means for achieving this end is the critical method. The title of the work is ambiguous in both English and German: Pure reason may be the agent or the object of the critique.3 In fact, it is surely both. The critical method requires reason to critique itself, to determine its own limits, and then to devise rules for staying within them. This, Kant thinks, is the key to reason’s “complete satisfaction”: “there is not a single metaphysical problem which has not been solved, or for the solution of which the key at least has not been supplied” (A xiii). Understood in this way, Kant’s critical method hardly seems revolutionary. It had been exemplified already in Locke’s Essay concerning Human Understanding and Hume’s Treatise of Human Nature. Both were attempts to define the limits of human knowledge by employing reason in a reflective act of self-criticism. Kant’s most important contribution is not the general idea of the critical method, but the specific form that method takes, for which he often uses the adjective transcendental rather than critical. Kant claims that he uses the transcendental method and establishes the truth of transcendental idealism. What, then, is the transcendental method? To understand it, we need to focus on what, in the preface to the second edition of 1787, Kant considers the key to his advance: his Copernican revolution in philosophy. “[T]he procedure of metaphysics,” Kant writes, “has hitherto been a merely random groping, and, what is worst of all, a groping among mere concepts” (B xv). Kant finds himself capable of setting metaphysics upon the secure path of a science by advancing a hypothesis analogous to that of Copernicus. Hitherto it has been assumed that all our knowledge must conform to objects. But all attempts to extend our knowledge of objects by establishing something in regard to them a priori, by means of concepts, have, on this assumption, ended in failure. We must therefore make trial whether we may not have more success in the tasks of metaphysics, if we suppose that objects must conform to our knowledge. (B xvi) Copernicus explained the motions of the heavenly bodies as resulting, not just from their own motion, but also from the motion of the observers on earth. Just as he sought “the observed movements, not in the heavenly bodies, but in the spectator” (B xxii n.), so Kant seeks the laws governing the realm of experience not in the objects themselves but in us: “we can know a priori of things only what we ourselves put into them” (B xviii). THE PLATONIC HERITAGE Kant is a rationalist. We might define a concept rationalist as one who believes in innate concepts—that is, that we have first-order cognitive abilities that we do not derive from experience—and a judgment rationalist as one who believes that we can know some synthetic truths a priori that is, that we can know independently of experience some truths that are not merely linguistic or verbal, that are not automatically true or false because of the meanings of the words that constitute them. Kant is plainly a rationalist in both senses. He argues that we can deduce pure concepts of the understanding a priori, independently of experience, from the mere possibility of experience, and moreover that there are synthetic a priori truths—that is, truths that we can know independently of experience but that are not merely verbal. Indeed, the establishment of rationalism in both senses seems to be a major goal of the Critique. Like many rationalists, Kant understands himself as working within the Platonic tradition. The central problems he attacks and his solutions to them stem directly from that tradition. To understand Kant’s Copernican revolution, therefore, we must consider the framework in which his thought is embedded. Consider a judgment of perception, for example, (said pointing to a figure drawn on a blackboard) ‘This is a triangle.’ According to Plato, at one very influential stage of his thought, at least, the mind so judging is Janus-faced. It is turned toward a perceptual object, a triangle, if it judges correctly. It is also turned toward the abstract form of a triangle. Both the object and the form have real causal or explanatory power. The object is causally responsible for our perception of it. But we are able to perceive it as a triangle because we apprehend the general form of triangularity. The form of a triangle is exemplified in the triangle itself, which in turn is an instance of, or, in Plato’s technical language, participates in, the form. The forms constitute the most distinctive feature of Plato’s philosophy of mind. They explain our ability to think general thoughts; they account for regularities as well as changes in experience; they explain how different people (or the same person at different times) can think the same thought; and they explain how thoughts can be veridical. We may think general thoughts, for example, by thinking about the forms and how they relate. Regularities in experience involve constant relations of forms; changes occur when an object of sense stops participating in one form and begins participating in another. Two different people can think the same thought by attending to the same forms. Finally, thoughts can depict reality accurately by involving the forms that are actually instantiated. But the forms also generate a serious epistemological puzzle. By definition, the forms are not themselves objects of experience; we do not perceive triangularity as we perceive individual triangles. How, then, do we know anything about them? How is the realm of forms, which Philo of Alexandria later termed “the intelligible world,” intelligible? In an Aristotelian philosophy of mind, we generate our own general concepts from experience through a process of abstraction. A Platonist may borrow this account for certain general concepts, but cannot use it for all, because it is central to Platonism that some forms are ultimately responsible for our abilities to think the corresponding thoughts. On Plato’s view, we do not abstract the idea of a pure triangle from triangular objects we perceive; indeed, we never encounter a pure triangle in experience. Instead, we recognize objects as triangular because we apprehend the form of pure triangularity and recognize that the objects approximate that pure form. In this sense, the forms have causal power; we are able to think of things as triangular by virtue of our apprehension of the form. Unfortunately, Plato has no theory that explains our interaction with the forms. He relies on two metaphors. In the Meno, he speaks of recollection; we apprehend the forms by recalling a time before birth when our souls were united with them. In the Republic, he speaks of the form of the Good as analogous to the sun, shedding light on the realm of forms and making possible our apprehension of them. Neither metaphor yields a satisfactory theory within the limits of Platonic metaphysics. Neither, moreover, seems to explain our apprehension of forms without begging the question. The Meno metaphor explains the causal efficacy of the forms now by appealing to their efficacy at some earlier time; the Republic metaphor, by appealing to the efficacy of the form of the Good. The Neoplatonic theory of emanation, according to which the entire realm of forms is ordered, with the causal efficacy of higher levels making lower levels possible and intelligible, does little to change the central epistemological difficulty. Augustine, however, solves Platonism’s epistemological problem by going beyond the resources of the original theory. To put it crudely, he adopts the Republic’s solution, but replaces the form of the Good with God. It is not clear why the form of the Good should be more causally efficacious than any other form. Causal efficacy, in contrast, is not a problem for God, who can do anything. Augustine thus follows Philo in identifying the forms with ideas in the mind of God, and describes the process by which we apprehend the forms as illumination, an act of revelation by which God allows us to make use of a portion of divine mental resources and by which, therefore, God makes our minds resemble the divine mind. We have innate cognitive capacities that reflect the principles according to which God created the world. Platonism remained Augustinian throughout the medieval debates concerning realism and nominalism arising from the conflict between Platonic and Aristotelian theories of substance and knowledge. Descartes, however, advanced a new kind of skeptical argument that forced a change in Platonism and that brought the theory of knowledge to center stage in modern philosophy. He added to the traditional arguments of Sextus and Cicero the possibility of an evil deceiver, who systematically misaligns our minds to reality. This extends farther than traditional skeptical arguments, for it raises the possibility that not only sensible knowledge but even logic and mathematics might be mistaken. It thus challenges the Augustinian solution to Platonism’s epistemological problem. Why should illumination produce veridical knowledge? Why should we believe that God reveals the portion of the divine mind relevant to the construction of the world, and not some counterfeit of it? Why should our innate ideas, and the a priori knowledge arising from them, have anything to do with the world? Kant sees the force of this difficulty, and thinks that, within the Platonic framework, it is insoluble. He divides previous philosophers into dogmatists and skeptics (A ix; A 856, B 884). Dogmatists like Descartes and Leibniz assume that human reason can comprehend ultimate reality. Their dogmatism involves three factors: 1 Realism. Human thought can discover the nature of objective reality. 2 Transcendence. Real knowledge is capable of extending beyond experience to the supersensible. (See A 295–6, B 352.) 3 Rationalism.4 Descartes, for example, tries to demonstrate that God guarantees the veridicality of our a priori judgments by arguing that God exists and is entirely good. A good God, surely, would not be a deceiver. Granting Cartesian rationalism, we may see the problem generated by the possibility of the evil deceiver as precisely that of realism: Why should we believe that our thinking can discover the nature of objective reality? Descartes’s solution relies on transcendence. We may take the form of thought implicit in the cogito, namely, the method of clear and distinct ideas, and apply it beyond the realm of our own thinking to reality—indeed, to reality that transcends all possible experience. But this, Kant sees, is just what is at issue. If realism is false—if our minds cannot discover the nature of objective reality—then why should we expect our modes of thinking, applied to the nature of that reality, to be reliable? It will not do to appeal to transcendence to justify realism, for the only argument for transcendence presupposes realism. For example, Descartes’s third Meditation, arguing for the existence and moral excellence of God, appeals to the premise that there is at least as much reality in the cause as in the effect.5 Why, given only the certain knowledge that I think and I exist, should I accept this principle as certain? Descartes derives it by applying the method of clear and distinct ideas beyond the mental realm of the cogito, which first justified it, to the realm of external, objective reality. Kant, for this reason, among others, rejects Descartes’s proof. But his reasoning is broader. Any argument for realism within the dogmatist’s framework will rely on transcendence and make a similarly illegitimate move. Skepticism, as Kant conceives it, also involves three factors: 1 Subjectivism. Knowledge of objects reduces to knowledge of sense. 2 Immanence. Real knowledge is limited to the sphere of sense experience. 3 Empiricism. (The denial of rationalism in either of its forms.) Skepticism, too, encounters difficulties. If dogmatism extends our knowledge too far and too uncritically, skepticism seems unable to account for the knowledge we do have. Hume’s scandal of induction, for example, illustrates that we cannot justify any causal knowledge we claim to have. It would have to reduce to a knowledge of items directly presented in sensation, but, as Hume shows, it does not. Kant’s critical philosophy shares the immanence of skepticism, but also the rationalism of dogmatism. It transcends the distinction between realism and subjectivism, holding that in a sense each is correct. Kant’s synthesis of dogmatism and skepticism comes at the cost of distinguishing between the world of appearance—the phenomenal world—and the world of things-in-themselves—the noumenal world. The former is essentially sensible, and human thought can discover its nature. Things-inthemselves, in contrast, lie beyond our cognitive capacities. The dogmatist is right about the possibility of knowledge of objects, even a priori knowledge of them; the skeptic is right about the limitation of knowledge to the realm of experience. Both, however, misunderstand the status of objects of experience, thinking that they are in themselves as they appear to us. The phenomenal world is both sensible and knowable; the noumenal world is neither. With respect to phenomena, therefore, the skeptic is vanquished; we can have a priori knowledge of objects of experience. With respect to noumena, however, the skeptic triumphs, for we can have no knowledge of things-inthemselves. Kant’s solution to the epistemological problem of Platonism goes beyond the distinction between phenomena and noumena. It would be easy to build that distinction into Descartes’s metaphysics, for example, without thereby making any headway on the skeptical problem. The key to Kant’s solution resides in two additional changes to the traditional framework. First, Kant explains the causal efficacy of the forms by transforming them into categories, pure concepts of the understanding. They are innate cognitive capacities of a very general kind, but they are wholly mental; the question of their correspondence to abstract, mindindependent forms cannot arise. Without such forms there remains, of course, the possibility that the categories do not correspond to objective and concrete reality. So, second, Kant reverses the traditional conception of the relation between thought and its object, or, as he puts it, between object and concept. The Platonist traditionally sees the object as causally responsible for the veridical, perceptual thought of it. Kant’s Copernican revolution is precisely to reverse this understanding, maintaining instead that thought is causally responsible for constituting the object. The result is not anarchy, a circumstance of “thinking making it so,” for the constitution of objects proceeds according to the categories in a rulegoverned way. The rule-governed character of the construction makes knowledge of objects possible. More, it makes a priori knowledge of them possible, for we can understand what we put into them—we can discover the rules according to which we constitute them. In this way Kant justifies his realism with respect to the phenomenal world without any appeal to transcendence—indeed, in the face of its outright denial. THE CATEGORIES Kant’s first change to the traditional Piatonistic framework is to substitute for the forms the categories, pure concepts of the understanding. These are innate ideas of the kind smiled upon by every concept rationalist. But there is no abstract realm of forms to which they must correspond. Their independence dissolves the epistemological difficulty arising for the aspect of the mind turned toward the forms in Platonic theories of mind. All knowledge, Kant observes, involves concepts; all concepts, in turn, “rest on functions,” “bringing various representations under one common representation” (A 68, B 93). The representations united in a concept may be sensible intuitions or other concepts. Kant here makes an important concession to empiricists such as Hume: the content of concepts traces ultimately to sensation. Kant makes much of this in the Transcendental Dialectic to refute the transcendence thesis. In deriving the categories, however, he focuses on the mediate character of concepts. Concepts of objects always relate to those objects indirectly: Since no representation, save when it is an intuition, is in immediate relation to an object, no concept is ever related to a concept immediately, but to some other representation of it, be that other representation an intuition, or itself a concept. Judgment is therefore the mediate knowledge of an object, that is, a representation of a representation of it. (A 68, B 93) This has the consequence, critical to the Copernican revolution Kant means to effect, that both judgments and objects are products of synthesis. Knowledge, Kant contends, always takes the form of judgments. (This is true at least for discursive knowledge, that is, knowing that, as opposed to knowing how or knowing to.) Judgments are combinations of concepts, which, in turn, are rules for synthesis, bringing together various sensations or concepts. Concepts relate to objects because they are such functions of synthesis. To discover the pure concepts of the understanding, therefore, we must find the functions of synthesis with a priori rather than empirical origins. The content of judgments, we might say, always has an empirical source, for the content of the concepts that comprise them arises ultimately from sensation. A concept unites sensible intuitions or other concepts that themselves unite sensible intuitions or other concepts. The chain cannot proceed to infinity; at some point, it terminates in intuition. This may suggest that there are no pure concepts. But not all functions of synthesis operating in a judgment comprise part of its content. A judgment has both a content and a form. The content stems from experience, but the form does not. We can identify the pure concepts of the understanding, then, by examining the forms of judgment. Fortunately, there is already a science that abstracts from the content of judgments and examines only their forms—logic.6 Kant, using Aristotelian logic, derives the following table of judgments (A 70, B 95): Every judgment, Kant contends, has a quantity, a quality, a relation, and a modality. In quantity, it is either universal (‘every metal is a body,’ for example), particular (‘some metals are yellow’), or singular (‘Socrates is a philosopher’). In quality, it is either affirmative (‘Socrates is mortal’), negative (‘Socrates is not mortal’), or infinite (‘Socrates is immortal’). In relation, judgments may be categorical (‘gold is a metal’), hypothetical (‘if every metal is a body, gold is a body’), or disjunctive (‘gold is a metal or a rare earth’). And, in modality, judgments are problematic (‘gold may be a metal’), assertoric (‘gold is a metal’), or apodeictic (‘gold must be a metal’). The table of judgments thus gives what Kant takes to be an exhaustive account of the forms of judgment. From the perspective of modern logic, the table seems incomplete. It does not include the quantity of ‘most metals are heavy’ or ‘many metals oxidize’; it omits the modality of ‘Socrates ought to avoid hemlock.’ It has no place for judgments with complement clauses, such as ‘Socrates knew that the hemlock would kill him,’ and makes no provision for the abstraction relating ‘kind’ and ‘kindness,’ ‘friend’ and ‘friendship.’ It is silent about verb tense and aspect. (Kant considers time a form of sensibility, not of judgment, and so considers it beyond the province of logic.) It omits identity. Kant’s table is not only incomplete from a modern point of view; it is redundant. Many entries can be derived from others with the help of forms recognized by contemporary logicians. There is no consensus on exactly what such a table would need to reflect all the forms of possible judgment. Kant is surely correct, however, that what we now call quantifiers, connectives, and modalities are required. The functions of judgment are not themselves the pure concepts of the understanding, but they correspond to them one-to-one. Kant lists the pure concepts of the understanding in his table of categories (A 80, B 106): Some of these relate directly to a corresponding entry in the table of judgments—‘Negative’ and ‘Negation,’ for example, or ‘Problematic’ and ‘Possibility—Impossibility.’ Other connections—‘Disjunctive’ and ‘Of community,’ for instance—seem tenuous. How does Kant derive the table of categories? His detailed arguments are not terribly important, for, as we have seen, the entries on the table of judgments reflect an outdated logic. But it is important to understand what the categories are. Roughly speaking, what the table of judgments is to judgments, the table of categories is to objects. Just as the table of judgments outlines the possible logical forms of judgment, so the table of categories outlines the possible logical forms of objects. This explains, for example, why, corresponding to the assertoric modality, we find ‘Existence-nonexistence’ rather than Truth-falsehood.’ Synthesis of the manifold of intuition is essential to concepts. But synthesis alone does not suffice for knowledge. Knowledge of objects requires a unification of the pure synthesis of the sensible manifold. That is, the concept of an object is special: It is the concept of a unified thing. In different terminology, concepts of objects not only tell us when a certain predicable or general term applies, but also when it is being applied to one and the same thing.7 The pure concepts of the understanding “apply a priori to objects of intuition in general” (A 79, B 105); they spell out the possible forms of such objects by indicating the possible kinds of unity. Kant’s key assumption in deriving the categories in this way is that “The same function which gives unity to the various representations in a judgment also gives unity to the mere synthesis of various representations in an intuition” (A 79, B 105). Each such unity is a pure concept of the understanding. Why are the unifying functions in judgments and objects the same? We have seen above that judgments and objects are both products of synthesis. Moreover, knowledge is always knowledge of objects through judgments. This suggests that judgments, at least of the sort appropriate to knowledge, are possible only by virtue of the unifying activity of the categories. Still, this does not suffice to establish the identity of function. It shows that the unifying activity in a judgment presupposes the unifying activity in an intuition, not that they have the same form. Kant’s argument turns on his notion of a concept. The unity of judgments and objects alike is a unity in a concept. This not only explains the link between the table of judgments and the table of categories; it also explains why the pure concepts of the understanding have a priori validity, avoiding the challenges of the skeptics. Concepts of objects in general thus underlie all empirical knowledge as its a priori conditions. The objective validity of the categories as a priori concepts rests, therefore, on the fact that, so far as the form of thought is concerned, through them alone does experience become possible. They relate of necessity and a priori to objects of experience, for the reason that only by means of them can any object whatsoever of experience be thought. (A 93, B 126) To understand the role that concepts play in Kant’s theory of mind, however, we must examine his account of the kinds of synthesis. THE SUBJECTIVE DEDUCTION Kant’s argument for the first key to his solution to the problems arising from the Platonic framework—the pure concepts of the understanding— also defends and develops the second key, the Copernican revolution. The argument occupies the portion of the Critique he entitles “The transcendental deduction of the pure concepts of the understanding.” There are, however, two very different versions of this argument in the first and second editions of the Critique. The first edition version presents a model of how the mind constructs objects from the data of sense, arguing that the pure concepts of the understanding are essential to the process. The second version presents no model, but analyzes the implications of the “I think.” The general strategy, however, remains the same. The categories are “concepts of an object in general” (B 129); they are “a priori conditions of the possibility of experience” (A 94, B 126). We are able to experience objects, that is, only because we have the concept of an object. We do not derive this concept from experience, for we could not experience anything as an object without already having the general concept of an object. The transcendental deduction of the first edition is notoriously difficult; Kant apparently pieced it together from four manuscripts composed at different times and reflecting four different stages of his thinking.8 It moreover includes two arguments: an “objective” deduction seeking to establish “the objective validity of a priori concepts,” and a “subjective” deduction investigating “the faculty of thought” (A x–xi). The subjective deduction outlines a three-part model of mental activity—specifically, of the generation of a judgment of experience such as ‘This is a triangle.’ This model shows, in Kant’s view, how judgments of experience require the categories. Kant defines a pure concept of the understanding as a concept without any empirical content, that is, as one that “universally and adequately expresses…a formal and objective condition of experience” (A 96). His strategy is to “prove that by their means alone an object can be thought” (A 97). This, he says, “will justify their objective validity,” for, if the categories are necessary conditions of experience, nothing could be an object of experience without complying with the categories. Sensation, Kant holds, is a manifold. It bombards us with a plethora of possible sources of information. Out of this multiplicity we synthesize representations, concepts, and judgments. The first act of synthesis is that of apprehension in intuition. All sensations occur in time.9 We bind the multiplicity sensation offers into unified items of sense. A sensation of a triangle, for example, may consist of various visual and tactile impressions received over a short interval of time. We experience it as a single sensation, usually without being aware of its complex nature. In short, we organize the data of sense into discrete sensations. This organization is the synthesis of apprehension in intuition. The second act is the synthesis of reproduction in imagination. Kant argues that “experience as such necessarily presupposes the reproducibility of appearances” (A 101–2). His premises concern pure intuitions of space and time—drawing a line in thought, for example, or thinking of a number—which, he maintains, are possible a priori. Kant’s theory of pure intuitions is controversial and somewhat obscure. But we can argue the point on other grounds. Sensations, considered individually, are not fullblown objects of experience. We can have many sensations of the same object. We might view a triangle, for example, from many different perspectives. To make any judgment about such an object of experience, we must relate sensations to each other, being capable of recognizing them as sensations of the same object. How we do this is of course an empirical question. But do it we must if we are ever to form concepts of objects of experience. That brings us to the third act, the synthesis of recognition in a concept. Throughout this discussion, Kant seems to operate with two ideas of what concepts are. The awareness of the unity of various sensations, Kant says, is a concept—etymologically, a “thinking together.” Having related sensations in the synthesis of reproduction in imagination, we form a concept through our consciousness of their unity as an object. But Kant also speaks of a concept as a rule: “a concept is always, as regards its form, something universal which serves as a rule” (A 106). Specifically, a concept is a rule for the synthesis of the manifold of intuition. These two notions of concepts are intimately connected: the unity which the object makes necessary can be nothing else than the formal unity of consciousness in the synthesis of the manifold of representations. It is only when we have thus produced synthetic unity in the manifold of intuition that we are in a position to say that we know the object. But this unity is impossible if the intuition cannot be generated in accordance with a rule by means of such a function of synthesis as makes the reproduction of the manifold a priori necessary, and renders possible a concept in which it is united. Thus we think of a triangle as an object, in that we are conscious of the combination of three straight lines according to a rule by which such an intuition can always be represented. This unity of rule determines all the manifold, and limits it to conditions which make unity of apperception possible. (A 105) Essential to recognizing something as an object, then, is a consciousness of its unity. But this consciousness is possible only if the object is constructed according to a rule. We can recognize a collection of intuitions as constituting a single object only by having a rule for uniting them into that object. We take a triangle as a single object rather than three distinct line segments that happen to intersect because we have a rule for uniting those segments. Without such a rule, we would be left with a manifold. The two notions of concept are connected, then, in that we are aware of unity (concept in sense one) according to a rule (concept in sense two). The rule-governed character of object construction brings with it a kind of necessity. To count as a triangle, for example, something must be a plane figure with three sides and three angles. So, it is a necessary truth that triangles have three sides and three angles. This, it might seem, is not the sort of necessity that interests Kant; ‘triangles have three angles’ is analytic. But when we ask what necessary truths stem, not from the rule for constructing triangles or any other kind of object, but from the rulegoverned constructions of objects in general, we obtain a more interesting answer. All objects must be unified, for example; the concept of an object is the concept of a single thing. Necessity, in turn, implies transcendental conclusions about our contributions to objects. All necessity, without exception, is grounded in a transcendental condition. There must, therefore, be a transcendental ground of the unity of consciousness in the synthesis of the manifold of all our intuitions, and consequently also of the concepts of objects in general, and so of all objects of experience, a ground without which it would be impossible to think any objects for our intuitions. (A 106) Kant’s argument begins with the premise that necessity is grounded in a transcendental condition. He does not argue for it because he takes it as evident from Hume’s writings. Necessary connections, Hume observes, cannot be found in experience. We are directly aware of a succession of things but not of the connections between items of the sequence. (In Frank O’Malley’s words, “Life is just one damned thing after another.”) Our concept of necessity, Hume concludes, must come from us, not from what we experience. So far, Kant agrees. But Hume goes on to attribute the source of our concept of necessity to the passionate side of our nature, to a feeling of expectation. Kant, in contrast, finds necessity’s source in the unity of objects. We experience objects, not just a whirling mass of sensations. And, as we have seen, it is a necessary truth that all objects are unified. Kant concludes that there is a transcendental ground of that unity. The source of the unity of objects, moreover, is also the source of the concept of an object in general; it thus underlies our experience of any object. The transcendental ground of the unity Kant terms transcendental apperception. When we reflect on the contents of our own consciousness, as Hume stresses, we are aware only of a succession of mental states; we do not confront a unified self. The contents of consciousness are always changing: “No fixed and abiding self can present itself in this flux of inner appearances” (A 107). Thus, we find no unity in what Kant calls empirical apperception or inner sense. But there must be a ground of unity in us. This brings us to Kant’s key contention: The ground of the consciousness of unity is the unity of consciousness. The source of our consciousness of the unity of objects is the underlying unity of our consciousness itself. This unity of apperception is “the a priori ground of all concepts” (A 107), for all concepts unify the manifold of sensibility into objects. The most general concepts, relating to the form of an object in general, are the categories. The unity of apperception and with it the categories underlie the lawlike connections we find among objects of experience and the synthetic a priori knowledge we have of them. The subjective deduction, then, means to spell out Kant’s Copernican revolution in subjective detail. We can know certain truths about objects independently of experience, for we can uncover the pure concepts of the understanding relating to the form of an object in general. These concepts do not arise from experience; they underlie the possibility of experience. So, we can know a priori that any experience will conform to them. This establishes realism, the view that we can attain knowledge of objective reality, within the realm of objects of experience. It also establishes concept rationalism. Most importantly, it solves the traditional Platonic problem of the conformity of the world to our innate ideas without invoking God, ex caelo or ex machina. THE OBJECTIVE DEDUCTION Kant nevertheless views the subjective deduction as inessential to the success of the critical enterprise. He needs to establish the objective validity of the categories; he does not need to spell out the subjective details of the faculty of thought. Kant is trying to show that the categories underlie our judgments about objects. Judgments, however, are the products of the threestage model of mental activity outlined in the subjective deduction, and the categories enter the model only in the third stage. The first two stages are thus inessential to the argument. The subjective deduction, moreover, treats the crucial third stage cursorily, leaving the role of the categories unclear. So, Kant begins another argument, the objective deduction, to treat only the relation between judgments and the categories. In the second edition, Kant omits the subjective deduction entirely and elaborates the objective deduction of the first edition. Kant begins, not by considering the process of transforming the data of sense into judgments, but by reflecting on the form of sensibility itself. “We must begin with pure apperception,” he says. “Intuitions are nothing to us, and do not in the least concern us if they cannot be taken up into consciousness” (A 116). That is, the model of mental activity presented in the subjective deduction presupposes, even at its earliest stage, the unity of consciousness. It relates the data of sense to a single consciousness or mind in which reside the faculties of sensibility, imagination, and understanding. For the manifold representations, which are given in an intuition, would not be one and all my representations, if they did not all belong to one self-consciousness. As my representations (even if I am not conscious of them as such) they must conform to the condition under which alone they can stand together in one universal selfconsciousness, because otherwise they would not all without exception belong to me. (B 132–3) The unity of consciousness thus underlies the possibility of sensation and thought. Kant obtains “the transcendental principle of the unity of all that is manifold in our representations, and consequently also in intuition” (A 116), which he terms “the highest principle in the whole sphere of human knowledge” (B 135). All representations are representations precisely because they can be represented in empirical consciousness. But an empirical consciousness requires a transcendental consciousness, for it is unified without containing its unity as an element. All representations therefore presuppose the transcendental unity of apperception. To put Kant’s argument differently: Empirical consciousness, as far as its contents are concerned, is a mixed bag. We cannot discover its unity from its contents. Nor can we determine that a given succession of mental states is unified into a single empirical consciousness by examining the contents of those states: “the combination (conjunctio) of a manifold in general can never come to us through the senses, and cannot, therefore, be already contained in the pure form of sensible intuition” (B 129). That a given representation is Jones’s representation, therefore, we cannot analyze by appeal to monadic properties of that representation. We cannot analyze it by appeal to relations among representations. We must instead analyze it by appeal to a relation between the representation and something else. Whatever is responsible for the unity of consciousness is not to be found in empirical consciousness but in the relation between its contents and something else, outside and underlying empirical consciousness. That is the transcendental unity, “that which itself contains the ground of the unity of diverse concepts in judgment, and therefore of the possibility of the understanding, even as regards its logical employment” (B 131). At one point Kant even identifies the transcendental unity with the understanding (B 134 n.). The transcendental unity of apperception manifests itself in the ‘I think’ that we can append to all our judgments and representations: It must be possible for the ‘I think’ to accompany all my representations; for otherwise something would be represented in me which could not be thought at all, and that is equivalent to saying that the representation would be impossible, or at least would be nothing to me. (B 132) This argument for the transcendental unity of consciousness allows Kant to speak of a transcendental principle: “a principle of the synthetic unity of the manifold in all possible intuition” (A 117). The principle of the unity of consciousness itself is analytic, roughly of the form ‘I am I’ (B 135). But the transcendental principle Kant obtains from it is nonetheless synthetic. We have seen that a sensation is part of Jones’s empirical consciousness if and only if it stands in the appropriate relation to Jones’s transcendental unity of apperception. This, Kant insists, is a necessary truth about our kind of consciousness, one which permits a priori knowledge of the unity of consciousness without manifesting that unity explicitly in its contents. It follows that Jones can receive a sensation only if it stands in relation to Jones’s transcendental unity. We can know a priori, then, that any sensation must relate to the transcendental unity: “all the manifold of intuition should be subject to conditions of the original synthetic unity of apperception” (B 136). This proposition, furthermore, is synthetic. We derive it, not by analyzing the concept of sensation or even the concept of the transcendental unity, but by connecting the two by way of the transcendental argument just reviewed. As we might expect concerning the argument for any synthetic truth, it rests on experience. But it permits a priori knowledge, knowledge that can be derived independently of experience and that holds necessarily, because it concerns the form of any possible experience. Kant is driving toward the conclusion that “appearances have a necessary relation to the understanding” (A 119). Appearances, he says, are “data for a possible experience”; they therefore have to relate to the understanding. The transcendental unity of apperception is responsible for what Kant calls the affinity of our representation—that is, their being our representations, their constituting a single empirical consciousness—and also the rule-governed character of the synthesis of the manifold of intuition. If that synthesis were not rule-governed, the combination of the data of sense would not yield knowledge but random and “accidental collocations” (A 121) such as the products of imagination in the usual sense. We may freely combine concepts, to form the notion of a threeheaded dragon or a golden mountain, but we gain no knowledge of what is actual from exercising that freedom. We attain knowledge of objects because the construction of objects actually presented in experience is rulegoverned. Sensibility presents us with the data of experience, giving it the form of space and time; the understanding formulates judgments. The rulegoverned synthesis linking the two is a product of the imagination and is unified by pure apperception. Our perception of a triangle, for example, is rule-governed; we cannot connect any sensations we like, label them a triangle, and obtain knowledge. The rule, in this case, is quite specific about geometrical form. Underlying such specific rules, Kant points out, is a general set of rules for generating concepts of objects. We can call something a triangle only if it has three sides and three angles. More broadly, we can call something an object only if it meets certain conditions, that is, satisfies certain rules. Those rules are specified by the categories. Kant therefore characterizes the understanding as the faculty of rules. The objective deduction, Kant maintains, shows that we can know objects because we construct them: “Thus the order and regularity in the appearances, which we entitle nature, we ourselves introduce. We could never find them in appearances, had not we ourselves, or the nature of our mind, originally set them there” (A 125). The understanding, consequently, is nothing less than “the lawgiver of nature” (A 126). This follows from Kant’s argument, for it has shown that the transcendental unity is “an objective condition of all knowledge. It is not merely a condition that I myself require in knowing an object, but is a condition under which every intuition must stand in order to become an object for me” (B 138). THE DIALECTIC The Transcendental Analytic and related portions of the Critique attempt to justify Kant’s rationalism. The Transcendental Dialectic, which comprises most of the second half of the book, tries to justify Kant’s thesis of immanence. As Kant puts it, the topic of the Dialectic is illusion. Certainly, he means to show that the hope of extending knowledge beyond the realm of sense experience is illusory. But he uses the term ‘illusion’ in a more specific sense: “an illusion may be said to consist in treating the subjective condition of thinking as being knowledge of the object” (A 396; see A 297, B 353–4). The key to the Analytic is the Copernican revolution, the idea that the faculty of thinking constitutes objects. This should not tempt us to conclude, however, that subjectivity and objectivity—thinking and knowing—match effortlessly. Clearly we may think of things that are not objectively real through imagination. We may also make mistakes. Most seriously, our thinking extends easily beyond the realm of sense experience. We may engage in metaphysical contemplation, arguing about the freedom of the will, the existence of God, and the mortality or immortality of the soul. But Kant denies that we can attain any real knowledge of these matters. Kant differentiates thinking and knowing, subjectivity and objectivity, by distinguishing the transcendental unity of apperception from the subjective unity of consciousness. To understand the distinction, we must return to the argument of the Transcendental Deduction, which uses the subjective unity to argue for the transcendental unity. The subjective unity of consciousness is a determination of inner sense. The manifold of intuition is given to us in experience, and our experience constitutes a single experience; this is the subjective unity. The manifold of intuition is united in the concept of an object through the transcendental unity. The subjective unity of consciousness is a condition of all thinking; the transcendental unity is a condition of all knowing. This distinction is extremely important for Kant; transcendent metaphysics results from its confusion. We may think whatever we like in imagination. We may connect concepts and intuitions freely without concern for their presence in experience. The transcendental unity, however, directs our thought toward an object and toward reality. We can know a synthetic judgment only by some connection with experience. This is why we cannot have knowledge that transcends experience: “The possibility of experience is, then, what gives objective reality to all our a priori modes of knowledge” (A 156, B 195). Indeed, it explains Kant’s first example of a synthetic a priori principle: “every object stands under the necessary conditions of synthetic unity of the manifold of intuition in a possible experience” (A 158, B 197). Kant’s distinction between the transcendental and subjective unities has two important consequences. First, a rational psychology—a discipline taking the ‘I think’ as its sole text (A 343, B 401) and amounting to a theory of the soul—is impossible. One might suppose, given the account of the transcendental unity, that the “I,” or, to use Kant’s term, the soul, is a simple, unified substance, and that we can discover this a priori. This, however, is a confusion. One can argue that the representation of the “I” is a representation of a substance, of something simple and unified. But to deduce that the “I” is a substance, simple and unified, is to commit a fallacy.10 In fact, it is to invite the skeptic’s objections all over again. Nothing here guarantees the veridicality of our representations. From the perspective of transcendental (rather than rational, that is, rationalist and transcendent) psychology, the “I” is “completely empty”: “it is a bare consciousness which accompanies all concepts. Through this I or he or it (the thing) which thinks, nothing further is represented than a transcendental subject of the thoughts=X” (A 346, B 404). As with the self, so with things-in-themselves. The second consequence of Kant’s distinction is thus that knowledge of things-in-them-selves is impossible; knowledge is limited to the sphere of experience. The limits of knowledge become clear in thinking about the role of the categories. The pure concepts of the understanding are conditions of the possibility of experience. They have a priori validity, against the claims of the skeptic, because “all empirical knowledge of objects would necessarily conform to such concepts, because only as thus presupposing them is anything possible as an object of experience” (A 93, B 126). Objects of experience must conform to the categories. Objects beyond the realm of experience, however, face no such constraint. In fact, we have no reason to believe that the categories apply to them at all. The categories conform to objects of possible experience because we synthesize those objects from the data of sensibility. What lies beyond sensibility lies beyond the categories, for we have no reason to believe that it results from such a process of synthesis. This means that transcendent metaphysics is impossible. Metaphysical knowledge, to be interesting, must be knowledge of the world; it cannot be merely verbal. So, it must consist of synthetic propositions. Moreover, it cannot rely on experience; to be necessary and nonempirical, it must be a priori. Kant, as a rationalist, is committed to the possibility of synthetic a priori knowledge. But such knowledge is possible only transcendentally, that is, through the contemplation of what makes experience possible. We secure the possibility of synthetic a priori knowledge by arguing for the categories. They apply, however, only to objects of possible experience. Kant derives rationalism, therefore, only by undercutting transcendence. No other objects, besides those of the senses, can, as a matter of fact, be given to us, and nowhere save in the context of a possible experience; and consequently nothing is an object for us, unless it presupposes the sum of all empirical reality as the condition of its possibility. (A 582, B 610) We can witness Kant’s application of his principle of immanence in his refutation of the cosmological argument for the existence of God. That argument appears in Aquinas, for example, as follows: In the observable world causes are to be found ordered in series; we never observe, or even could observe, something causing itself, for this would mean that it preceded itself, and this is impossible. Such a series of causes, however, must stop somewhere. For in all series of causes, an earlier member causes an intermediate, and the intermediate a last (whether the intermediate be one or many). If you eliminate a cause, you also eliminate its effects. Therefore, there can be neither a last nor an intermediate cause unless there is a first. But if the series of causes goes on to infinity, and there is no first cause, there would be neither intermediate causes nor a final effect, which is patently false. It is therefore necessary to posit a first cause, which all call “God.”11 Kant’s transcendental critique of this argument alleges “a whole nest of dialectical assumptions,” of which he points out several: (a) The argument assumes that each event in the observable world has a cause. Kant agrees; he regards it as a synthetic a priori truth. But, as such, “This principle is applicable only in the sensible world; outside that world it has no meaning whatsoever” (A 609, B 637). (b) Why can’t a series of causes go on to infinity? Kant finds nothing to justify this assumption even in the sensible world, (c) Is it true that, if you eliminate a cause, you eliminate its effects? Even if this holds in experience, we have no justification for extending it beyond experience, (d) Finally, why should we identify the first cause as God? Philosophers have understood God as the perfect being, “that, the greater than which cannot be conceived,” the being more real than any other, and the necessarily existent being. To conclude that the first cause is God, we must show at least that the first cause is perfect and necessary. Nothing in the proof accomplishes this. Consequently, Kant maintains that “the so-called cosmological proof really owes any cogency which it may have to the ontological proof from mere concepts” (A 607, B 635), for it assumes that perfection, necessity, and being the first cause all hold of the same thing. The ontological proof appears in Anselm in the following form: Certainly, this being exists so truly that one cannot even think that it does not exist. For whatever must be thought to exist is greater than whatever can be thought not to exist. Hence, if that greatest conceivable being can be thought not to exist, then it is not the greatest conceivable being, which is absurd. Therefore, something so great that a greater cannot be conceived exists so truly that it cannot even be thought not to exist.12 The argument means to show that perfection entails necessity. That God is perfect Anselm takes as an analytic truth, as following from a definition of ‘God.’ He concludes that God exists necessarily. Kant’s assault on this argument is more complicated than his attack on the cosmological proof, but also more illuminating. This proof is a paradigm example of illusion, the mistaking of the subjective for the objective. It tries to establish the necessary existence of God from the mere concept of God. Kant is willing to grant that the argument shows that the concept of God, so defined, includes the concept of existence. But he denies that this implies anything at all about the existence of God in reality. The key to Kant’s attack on the ontological argument is his contention that ‘being’ is not a real predicate. Kant defines a determining predicate as “a predicate which is added to the concept of the subject and enlarges it” (A 598, B 626). It follows that a judgment with a determining predicate must be synthetic, for the predicate must enlarge the subject; it cannot already be contained in it. “‘Being’,” Kant insists, “is obviously not a real predicate; that is, it is not a concept of something which could be added to the concept of a thing” (A 598, B 626). A real predicate is capable of serving as a determining predicate. ‘Being,’ evidently, is not. We might be tempted to conclude that existential judgments such as ‘God is’ or ‘God exists’ are analytic, for ‘being’ cannot serve as a determining predicate. But Kant clearly maintains that all existential judgments are synthetic. He argues specifically that ‘God exists’ is not analytic, and concludes, “as every reasonable person must, that all existential propositions are synthetic” (A 598, B 626). It follows that ‘being’ cannot be contained in the concept of a thing. But how can existential judgments be synthetic if they lack determining predicates?13 A synthetic judgment is not merely verbal; its predicate, according to Kant, must add something not already included in its subject. ‘Being,’ then, must add something to every subject concept. Yet it is not determining; it does not add to and enlarge the subject concept. ‘Being’ adds something that does not enlarge the concept of the subject. To understand how this is possible, we must return to Kant’s theory of concepts. Concepts are functions of synthesis that organize and unify the material of sense. They mold the data of sense into perceptions of objects (A 68, B 93, B 95). Consequently, their content relates essentially to the manifold of sense. In language and in thought, we can manipulate items however we like. Only through links to intuition, actual or possible, can we move from thinking to knowledge, activating the transcendental unity and giving our thoughts objective validity. (See A 155, B 194–5, B 146, B 165–6.) In short, concepts have content by virtue of the patterns of possible intuitions falling under them. This entails that ‘being’ is not a real predicate, for it lacks this sort of content. It cannot enlarge a subject concept; any intuition falling under the concept of a dollar falls under the concept of an existing dollar, and vice versa (A 599–600, B 627–8). It follows, moreover, that existential judgments are synthetic, for existence cannot be part of the content of a subject concept (A 225, B 272). If ‘being’ lacks content definable in terms of the manifold of sense, what does it contribute to a judgment? Existential judgments do not enlarge or alter a rule for the synthesis of the manifold of intuition, but express the relation of the rule to the understanding. For Kant, then, ‘being’ is relational. The same holds of possibility and necessity, which share the fourth, “Modality” portion of the table of categories.14 Kant maintains that the modality of a judgment adds nothing to the judgment’s content. Instead, it determines the judgment’s relation to the understanding: “The principles of modality thus predicate of a concept nothing but the action of the faculty of knowledge through which it is generated” (A 234, B 286– 7). Existence and the other modalities contribute “a relation to my understanding” (A 231, B 284), determining “only how the object, together with all its determinations, is related to understanding and its empirical employment, to empirical judgment, and to reason in its application to experience” (A 219, B 266). Kant compares the ‘being’ at stake in existential judgments to the ‘being’ of the copula (A 74, B 100; A 598–9, B 626–7). Both “distinguish the objective unity of given representations from the subjective” (B 141– 2). Only by relating the terms of a judgment to the transcendental unity of apperception does there arise from this relation a judgment, that is, a relation which is objectively valid, and so can be adequately distinguished from a relation of the same representations that would have only subjective validity—as when they are connected according to the laws of association. (B 142) ‘Being’ in both roles distinguishes the subjective from the objective. This is why the ontological proof is Kant’s paradigm case of dialectical illusion. The advocate of the proof mistakes the subjective for the objective, failing to recognize that God’s existence or necessity cannot be established analytically, from the definition of ‘God’ alone. In saying that something exists, we assert a relation to the understanding; we assert that we may experience the object, or stand in relation to it by way of empirical laws (A 219, B 266–7; A. 234 n., B 287 n.; A 616, B 644). And this cannot be derived from concepts alone. It follows that nothing exists with analytic or logical necessity: If I take the concept of anything, no matter what, I find the existence of this thing can never be represented by me as absolutely necessary, and that, whatever it may be that exists, nothing prevents me from thinking its nonexistence. (A 615, B 643) We can now see how Kant can practice the transcendental method while rejecting transcendent metaphysics. The latter confuses the subjective and the objective, failing to recognize that concepts have content only in relation to experience. The transcendental method, however, focuses directly on the relation to the understanding at stake in questions of modality. Kant deduces the categories by reflecting on the sort of relation that must hold if experience of objects is to be possible. HUMANISM Kant carefully distinguishes his view from the idealism of Berkeley, which assails the notion of a reality beyond the realm of ideas. Kant’s solution to Platonism’s problems relies on distinguishing phenomena from noumena. Kant thus insists on the need to recognize nonmental objects, things-inthemselves, of which our appearances are appearances. Kant nevertheless realizes that his theory is a form of idealism— transcendental idealism, he calls it—for truth, objectivity, and existence, within the theory, become fundamentally epistemic notions. The same holds of all the modalities—possibility, truth or existence, and necessity — for all have the same function of relating a judgment to the understanding. Metaphysics is inseparable from epistemology; the root notions of metaphysics are all, in the end, epistemological notions. Kant’s epistemic conception of modality underlies his identification of a priori and necessary judgments. Saul Kripke has attacked this identification, pointing out that a prioricity is a matter of epistemology—can something be known independently of experience?—while necessity is a matter of metaphysics. Kripke has alleged, against Kant, that there can be contingent a priori and necessary a posteriori truths.15 This seems plausible on the metaphysical view of necessity that Leibniz and Kripke share, namely, that necessity is truth in all possible worlds. But Kant rejects that view. A judgment is a priori if it can be known independently of all experience; if, that is, it holds no matter what experience might yield, or, to put it differently, if it holds no matter what the world looks like. A judgment is necessary, on the Leibniz-Kripke view, if it holds no matter what the world is like. Kant does not confuse these notions; he rejects the latter precisely because it is metaphysical in a transcendent sense. The truth of skepticism is that we cannot know what the world is like. The only notion of modality we can use is epistemic, in which we consider possible experiences rather than possible worlds. On this conception, of course, the a priori and the necessary are not only equivalent, but obviously so. Moreover, it becomes possible to attain knowledge of necessary truths about objects of experience. Reason gets itself into trouble when it tries to leave the realm of possible experience. Kant is able to defend our knowledge of necessary truths against skeptics such as Hume because, for him, the a priori and necessary extend to the immanent sphere only, not to the transcendent. They are limited to the realm of possible experience. If a priori judgments were necessary in a strong metaphysical sense, then Kant’s immanence thesis would be hard to understand. The epistemic character of the basic notions of metaphysics—when these notions and, correspondingly, metaphysics are properly construed— is the central consequence of Kant’s Copernican revolution. It would become fundamental to virtually all nineteenth-century approaches to philosophy. Skepticism, perhaps the chief philosophical puzzle since Descartes, would give way to puzzles arising from Kant’s uniquely humanistic idealism. For Kant, as for the ancient Sophist Protagoras, man is the measure of all things. Kant, of course, takes the definite article here seriously. There is one and only one measure: the categories underlie all possible experience. Not everyone would agree. The nature and especially the uniqueness of the measure would define the chief battleground for philosophers during the next two centuries. NOTES 1 R.Rorty, Philosophy and the Mirror of Nature (Princeton: Princeton University Press, 1979), p. 149; N.Kemp Smith, A Commentary to Kant’s Critique of Pure Reason (Atlantic Highlands, NJ: Humanities Press, 1962), p. vii. 2 This and other citations from the Critique of Pure Reason are from the translation of N.Kemp Smith (London: Macmillan, 1929; New York: St Martin’s Press, 1965). Throughout, any emphasis in the quotations is Kant’s; the pagination is that of the original first (A) and second (B) editions. 3 H.Vaihinger, Commentar zu Kant’s Kritik der Reinen Vernunft, Vol. I (Stuttgart: Spemann, 1881), pp. 117–20. 4 The analysis is Vaihinger’s. See ibid., p. 50; Kemp Smith, op. cit., pp. 13–14. 5 Descartes, Meditations, III. 6 Kant often speaks of the content and form of judgments in just this way. Introducing the table of judgments, he writes, “If we abstract from all content of a judgment, and consider only the mere form of understanding,” we derive the table (A 70, B 95). At other times, however, he treats the form and content very differently. Modality, for example, differs from the other aspects of judgment in the table in that “it contributes nothing to the content of a judgment (for, besides quantity, quality, and relation, there is nothing that constitutes the content of a judgment)” (A 74, B 100). These are plainly inconsistent. In the former passage, Kant speaks of empirical content or, more precisely, the content of the impure concepts in a judgment; in the latter, he speaks of logical content. It is tempting to identify the form of a judgment with its logical content, but Kant’s theory of the modalities makes that impossible. See my “Kant on Existence and Modality,” Archiv für Geschichte der Philosophie, 64, 3 (1982): 289–300. 7 That is, concepts of objects are rules of individuation as well as application. For a sophisticated modern treatment of this distinction, see A.Gupta, The Logic of Common Nouns (New Haven: Yale University Press, 1984). 8 See H.Vaihinger, “Die transcendentale Deduktion der Kategorien,” Gedenkschrift für Rudolf Haym (1902); Kemp Smith, op. cit., pp. 202ff. 9 Kant’s theory of time occupies part of the Transcendental Aesthetic. In brief, time is the form of inner sense, the progression of sensations, thoughts, and, in general, representations that constitutes empirical consciousness. Space and time, Kant argues, are a priori forms of intuition, for they are necessary conditions of sensation. We cannot sense anything without sensing it in space and time, that is, as spatially and temporally located. Time is moreover the form of inner sense because we cannot think anything without thinking it in time, that is, without our thought being part of a temporal sequence. 10 See W.Sellars, “Some Remarks on Kant’s Theory of Experience” and “…this I or he or it (the thing) which thinks…,” in his Essays on Philosophy and its History (Dordrecht: Reidel, 1974), pp. 44–61, 62–92. 11 St Thomas Aquinas, Summa Theologiae, la. 2; my translation. 12 St Anselm of Canterbury, Proslogion, III; my translation. 13 For more on this apparent contradiction, see J.Shaffer, “Existence, Predication, and the Ontological Argument,” Mind, 71 (1962): 307–25; W.H.Walsh, Kant’s Criticism of Metaphysics (Edinburgh: Edinburgh University Press, 1975), p. 7; G.Vick, “Existence was a Predicate for Kant,” Kant-Studien, 61 (1970): 357–71, esp. 363–4; R.Coburn, “Animadversions on Plantinga’s Kant,” Ratio, 13 (1971): 19–29, esp. 21–2; R.Campbell, “Real Predicates and ‘Exists’,” Mind, 83 (1974): 96ff.; and my “Kant on Existence and Modality,” op. cit., pp. 291–5. 14 One of the few commentators to observe this is H.Heimsoeth, Transzendentale Dialektik (Berlin: de Gruyter, 1969), Vol. III, p. 480. 15 See S.Kripke, Naming and Necessity (Cambridge, Mass.: Harvard University Press, 1972, 1980), pp. 34–9. SELECT BIBLIOGRAPHY Original language editions 2.1 Kant, I. Critik der reinen Vernunft, Riga: J.F.Hartknoch, 1781. 2.2 Kants gesammelte Schriften, 29 vols, ed. Deutschen (formerly Königlich Preussische) Akademie der Wissenschaften, Berlin: de Gruyter (and predecessors), 1902–. 2.3 Kant, I. Werke, Academie Textausgahe: Anmerkungen der Bande I-IX, Berlin: de Gruyter, 1977. English translations 2.4 Kant, I. Critik of Pure Reason, trans. F.Haywood, London: W.Pickering, 1838. 2.5 Kant, I. Critique of Pure Reason, trans. J.M.D.Meiklejohn, New York: Colonial Press, 1899; London: J.M.Dent, 1934, 1940. 2.6 Kant, I. Critique of Pure Reason, trans. N.Kemp Smith, London: Macmillan, 1929; New York: St Martin’s Press, 1965. 2.7 Kant, I. Critique of Pure Reason, trans. W.Schwarz, Aalen: Scientia, 1982. Books on Kant (in English) 2.8 Beck, L.W. Early German Philosophy: Kant and his Predecessors, Cambridge, Mass.: Belknap Press of Harvard University Press, 1969. 2.9 Beck, L.W. Essays on Kant and Hume, New Haven: Yale University Press, 1978. 2.10 Beck, L.W. (ed.) Kant Studies Today, La Salle, Ill.: Open Court, 1969. 2.11 Beck, L.W. (ed.) Kant’s Theory of Knowledge, Dordrecht: Reidel, 1974. 2.12 Broad, C.D. Kant: An Introduction, Cambridge: Cambridge University Press, 1978. 2.13 Cassirer, E. Kant’s Life and Thought, trans. J.Haden, New Haven and London: Yale University Press, 1981. 2.14 den Ouden B.D., and Moen, M. (eds) New Essays on Kant, New York: Peter Lang, 1987. 2.15 Guyer, P. (ed.) The Cambridge Companion to Kant, Cambridge: Cambridge University Press, 1992. 2.16 Korner, S. Kant, Harmondsworth: Penguin, 1955. 2.17 Scruton, R. Kant, Oxford: Oxford University Press, 1982. 2.18 Walker, R.C.S. Kant, London: Routledge & Kegan Paul, 1978. 2.19 Werkmeister, W.H. Kant, the Archetectonic and Development of his Philosophy, La Salle, 111.: Open Court, 1980. 2.20 Wolff, R.P. (ed.) Kant: A Collection of Critical Essays, Notre Dame: University of Notre Dame Press, 1968. 2.21 Wood, A.W. (ed.) Self and Nature in Kant’s Philosophy, Ithaca: Cornell University Press, 1984. Books on the Critique of Pare Reason (in English) 2.22 Allison, H.E. Kant’s Transcendental Idealism: An Interpretation and Defense, New Haven: Yale University Press, 1983. 2.23 Ameriks, K. Kant’s Theory of Mind, Oxford: Clarendon Press, 1982. 2.24 Aquila, R.E. Representational Mind: A Study of Kant’s Theory of Knowledge, Bloomington: Indiana University Press, 1983. 2.25 Bennett, J. Kant’s Analytic, Cambridge: Cambridge University Press, 1966. 2.26 Bennett, J. Kant’s Dialectic, Cambridge: Cambridge University Press, 1974. 2.27 Brittan, G.G. Kant’s Theory of Science, Princeton: Princeton University Press, 1978. 2.28 Ewing, A.C. A Short Commentary to Kant’s Critique of Pure Reason, Chicago: University of Chicago Press, 1938. 2.29 Forster, E. (ed.) Kant’s Transcendental Deductions: The Three Critiques and the Opus Postumum, Stanford: Stanford University Press, 1989. 2.30 Kemp Smith, N. A Commentary to Kant’s Critique of Pure Reason, Atlantic Highlands, NJ: Humanities Press, 1962. 2.31 Paton, W.E. Kant’s Metaphysic of Experience, London: Allen & Unwin, 1970. 2.32 Prichard, H.A. Kant’s Theory of Knowledge, Oxford: Oxford University Press, 1909. 2.33 Rescher, N. Kant’s Theory of Knowledge and Reality: A Group of Essays, Washington: University Press of America, 1983. 2.34 Schaper, E., and Vossenkuhl, W. (eds) Reading Kant: New Perspectives on Transcendental Arguments and Critical Philosophy, Oxford: Blackwell, 1989. 2.35 Sellars, W. Science and Metaphysics: Variations on Kantian Themes, London: Routledge & Kegan Paul, 1968. 2.36 Seung, T.K. Kant’s Transcendental Logic, New Haven: Yale University Press, 1969. 2.37 Strawson, P.F. The Bounds of Sense: An Essay on Kant’s Critique of Pure Reason, London: Methuen, 1966. 2.38 Walsh, W.H. Kant’s Criticism of Metaphysics, Edinburgh: Edinburgh University Press, 1975. 2.39 Wilkerson, T.E. Kant’s Critique of Pure Reason, Oxford: Oxford University Press, 1976. 2.40 Winterbourne, A. The Ideal and the Real: An Outline of Kant’s Theory of Space, Time, and Mathematical Construction, Dordrecht: Kluwer, 1988. 2.41 Wolff, R.P. Kant’s Theory of Mental Activity, Cambridge, Mass.: Harvard University Press, 1963.

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  • Kant, Immanuel — born April 22, 1724, Königsberg, Prussia died Feb. 12, 1804, Königsberg German philosopher, one of the foremost thinkers of the Enlightenment. The son of a saddler, he studied at the university in Königsberg and taught there as privatdocent… …   Universalium

  • Kant, Immanuel — (1724 1804)    by Alison Ross   Immanuel Kant s critical philosophy marks a turning point in modern thought. Kant distinguishes the critical inquiry he conducts into reason from the fanaticism that afflicts the dogmatic philosophy of his… …   The Deleuze dictionary

  • Kant, Immanuel — (1724 1804)    by Alison Ross   Immanuel Kant s critical philosophy marks a turning point in modern thought. Kant distinguishes the critical inquiry he conducts into reason from the fanaticism that afflicts the dogmatic philosophy of his… …   The Deleuze dictionary

  • Kant, Immanuel — (1724–1804) German philosopher and founder of critical philosophy. The son of a saddler, Kant was born and educated in Königsberg (Kaliningrad) in East Prussia. After leaving the university he spent a number of years in private tutoring, but… …   Philosophy dictionary

  • Kant, Immanuel — (1724 1804)    The founder of critical philosophy and one of the greatest philosophers of modern times, Kant began as a conventional pre critical philosopher building on the work of Leibniz and his main interpreter Christian Wolff. His monumental …   Christian Philosophy

  • Scientific revolution — This article is about a period in the history of science. For the process of scientific progress via revolution, proposed by Thomas Kuhn, see Paradigm shift …   Wikipedia

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