Critique of Pure Reason

Critique of Pure Reason
Title page of the 1781 edition

The Critique of Pure Reason (German: Kritik der reinen Vernunft ) by Immanuel Kant, first published in 1781, second edition 1787, is considered one of the most influential works in the history of philosophy. Also referred to as Kant's "first critique," it was followed by the Critique of Practical Reason and the Critique of Judgement. In the last section of the introduction (section VII: Idea and Division of a Particular Science, under the Name of a Critique of Pure Reason) Kant states that "... If this Critique itself does not assume the title of transcendental philosophy, it is only because, to be a complete system, it ought to contain a full analysis of all human knowledge a priori."

Before the time of Kant, it was generally held that whatever knowledge was a priori must be of the nature of an analytic judgment, that is, what is stated in the predicate must already be present in the subject and it is therefore, independent of experience (e.g., "An intelligent man is intelligent" or "An intelligent man is a man"). In either case, the judgment is analytic because it is arrived at by analyzing the subject. Before the time of Kant, it was thought that all judgments of which we could be certain a priori were of this kind: that in all of them there was a predicate that was only part of the subject of which it was asserted. If this were so, we would be involved in a contradiction every time we would try to deny anything that could be known a priori (e. g., "An intelligent man is not intelligent" or "An intelligent man is not a man"). Thus according to the philosophers before Kant, the Law of contradiction is sufficient to establish all a priori knowledge.[1]

Propaedeutic note to an examination of the Critique of Pure Reason:

The Aristotelean philosophers distinguished two kinds of judgments:

1) Synthetic judgment.- Judgments that are based on a synthesis or putting together of different facts of experience and are therefore considered to be a posteriori. For example, "... The phases of the moon are visible after dark."

2) Analytic judgment.- Judgments that are based exclusively upon an analysis of the subject without recourse to experience and are therefore considered to be a priori. For example, "... A right line is straight."

Kant is not entirely satisfied with these conclusions and argues that there are synthetic judgments a priori such as those of mathematics. Aristoteleans would argue that such judgments are really analytic.[2]


Kant's rejection of Hume's empiricism

Before Kant (1724–1804), David Hume (1711–1776) accepted the general view of rationalism about a priori knowledge. However, upon closer examination of the subject at hand, Hume discovered that some judgments considered to be analytical, especially those related to cause and effect, were in fact synthetical i. e. no analysis of the subject will reveal the predicate but depends exclusively upon experience and is therefore, a posteriori. Before Hume, rationalists had held that effect could be deduced from cause; Hume argued that it could not and from this inferred that nothing at all could be known a priori in relation to cause and effect. Kant who was brought under the auspices of rationalism was deeply disturbed by Hume's skepticism. "... Kant tells us that David Hume awakened him from his dogmatic slumbers."[3] Kant decided to find an answer and spent at least twelve years of meditation upon the subject.[4] However, Kant wrote the Critique of Pure Reason in a period between four or five months. At the same time, Kant was also lecturing and teaching. On the other hand, the Critique of Pure Reason embodies Kant's thoughts during the various stages of development of the entire period of meditation.[5]

Kant's work was stimulated by taking seriously Hume's skeptical conclusions about such basic principles as cause and effect and the implications of this skepticism for Kant's grounding in rationalism. In Kant's view, Hume's skepticism rested on the premise that all ideas are presentations of sensory experience. The problem that Hume identified was that basic principles like causality cannot be derived from sense experience only: as Hume argued, we experience only that one event regularly succeeds another, not that it is caused by it. In section VI (The Universal Problem of Pure Reason) of the introduction to the Critique of Pure Reason, Kant explains how Hume went so far but stopped short of considering that a synthetic judgment could be made 'a priori'. Kant's goal, then, was to find some way to derive cause and effect without relying on empirical knowledge. Kant rejects analytical methods for this, arguing that analytic reasoning can't tell us anything that isn't already self-evident (Bxvii). Instead, Kant argued that we would need to use synthetic reasoning. But this posed a new problem — how can one have synthetic knowledge that is not based on empirical observation — that is, how can we have synthetic a priori truths?

Synthetic Judgment a priori

Immanuel Kant, lecturing to Russian officers — by I. Soyockina / V. Gracov, the Kant Museum, Kaliningrad

Kant argues that there are synthetic judgments such as the connection of cause and effect (e.g., "... Every effect has a cause.") where no analysis of the subject will produce the predicate. Kant reasons that statements such as those found in Geometry and Newtonian physics are synthetic judgments. Kant uses the classical example of 7 + 5 = 12. No amount of analysis will find 12 in either 7 or 5. Thus Kant arrives at the conclusion that all pure mathematics is synthetic though a priori; the number 7 is after all seven and the number 5 is five and the number 12 is twelve and so on and so forth; in other words, they are universal and necessary. For Kant then, Mathematics is synthetic judgement a priori. This conclusion led Kant into a new problem as he wanted to establish how this could be possible: How is pure mathematics possible?[4] This also led him to inquire whether it could be possible to ground synthetic a priori knowledge for a study of metaphysics, because most of the principles of metaphysics from Plato through to Kant's immediate predecessors made assertions about the world or about God or about the soul that were not self-evident but which could not be derived from empirical observation (B18-24). For Kant, all post-Cartesian metaphysics is mistaken from its very beginning: the empiricists are mistaken because they assert that we cannot go beyond experience and the dogmatists are mistaken because they assert that we can go beyond experience by using theoretical reason exclusively. Therefore, Kant proposes a new basis for a science of metaphysics. How is then a science of metaphysics possible if at all? According to Kant, only practical reason, the faculty of moral consciousness, the moral law of which we are immediately aware, enables us to know things as they are.[6] This led to his most influential contribution to metaphysics: the abandonment of the quest to try to know the world as it is "in itself" independent of our sense experience. He demonstrated this with a thought experiment, showing that we cannot meaningfully conceive of an object that exists outside of time and has no spatial components and isn't structured in accordance with the categories of the understanding, such as substance and causality. Although we cannot conceive of such an object, Kant argues, there is no way of showing that such an object does not exist. Therefore, Kant says, the science of metaphysics must not attempt to reach beyond the limits of possible experience but must discuss only those limits, thus furthering the understanding of ourselves as thinking beings. For Kant then, the human mind is incapable of going beyond experience so as to obtain a knowledge of ultimate reality, because from pure ideas no direct advance can be made to objective existence.[7]

"Since, then, the receptivity of the subject, its capacity to be affected by objects, must necessarily precede all intuitions of these objects, it can readily be understood how the form of all appearances can be given prior to all actual perceptions, and so exist in the mind a priori" (A26/B42). Appearance is then, via the faculty of transcendental imagination, grounded systematically in accordance with the categories of the understanding. Kant's metaphysical system, which focuses on the operations of cognitive faculties, places substantial limits on knowledge not founded in the forms of sensibility. Thus it locates the error of metaphysical systems prior to Critique in failing to first take into consideration the limitations of our human capacity for knowledge. According to Heidegger, transcendental imagination is what Kant also refers to as the unknown common root uniting sense and understanding, the two component parts of experience. Transcendental imagination is described in the first edition of the Critique of Pure Reason but Kant omits it from the second edition of 1787.[8]

It is because of taking into account the role of our cognitive faculties in structuring the known and knowable world that in the second preface to the "Critique of Pure Reason" Kant compares his critical philosophy to Copernicus' revolution in astronomy. Kant writes: "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" (Bxvi). Just as Copernicus revolutionized astronomy by changing the point of view and taking the position of the observer into account, Kant's critical philosophy takes into account the position of the knower of the world in general and reveals its impact on the structure of his/her known world. According to Kant then, in explaining the movement of celestial bodies Copernicus rejected the view that the movement is in the stars and accepted it as being a part of the spectator. This is how Kant understands the Copernican Hypothesis and his philosophical parallel to it is clear and important. Knowledge does not depend so much on the object of knowledge as on the capacity of the knower.[9]

Kant's transcendental idealism should be distinguished from idealistic systems such as Berkeley's. While Kant claimed that phenomena depend upon the conditions of sensibility, space and time, and on the synthesizing activity of the mind manifested in the rule-based structuring of perceptions into a world of objects, this thesis is not equivalent to mind-dependence in the sense of Berkeley's idealism. Kant defines transcendental idealism:

"I understand by the transcendental idealism of all appearances the doctrine that they are all together to be regarded as mere representations and not things in themselves, and accordingly that time and space are only sensible forms of our intuition, but not determinations given for themselves or conditions of objects as things in themselves. To this idealism is opposed transcendental realism, which regards space and time as something given in themselves (independent of our sensibility)." (CPR, A 369)

According to Mortimer J. Adler, who considered himself an Aristotelean at heart, Kant's "mistake" of substituting idealism for realism is "... The most serious mistake that modern philosophy inherited from Kant." Knowledge is always the result of experience and since it is experienced by us, it is not and could never be, according to Kant, knowledge independent of our minds. Since it is not independent of our minds then it cannot be considered real for reality is independent of the human mind. For Kant, the only things that are independent of the human mind are "Dinge an sich", things in themselves, and these are intrinsically unknowable.[10]

Kant's approach

In Kant's view, a priori intuitions and concepts provide us with some a priori knowledge, which also provides the framework for our a posteriori knowledge. Kant also believed that causality is a conceptual organizing principle that we impose upon nature, albeit nature understood as the sum of appearances that can be synthesized according to our a priori concepts.

In other words, space and time are a form of perceiving and causality is a form of knowing. Both space and time and our conceptual principles and processes pre-structure our experience.

Kant's position commits him to the thought of a "thing-in-itself." Something affects our sensibility and thereby gives rise to a manifold of sensible intuition. Kant regards the thing-that-effects-us as a mind-independent object and calls it the thing-in-itself. Kant's position is that there is no point in asking whether there is a single thing-in-itself or many things-in-themselves that affect us (he indifferently speaks of it, or them, in both ways). To ask the question is to ask for a determinate judgment concerning the thing-in-itself. But a determinate judgment, or cognition ("erkenntnis" in German), is something that we can only obtain to with respect to appearances. So, although he insists that we must think of the thing in itself, and we must do so in accordance with the pure category of real ground/real consequent; we must never expect to have a cognition of things-in-themselves. More specifically, although some thing-in-itself must be thought of as the real ground of a real consequent in me (i.e., my having a manifold of intuition), I must not confuse that with the cognition of a temporally determined real ground or "cause" of my manifold of intuition.[11]

Things as they are "in themselves" — the thing in itself or das Ding an sich — are unknowable. For something to become an object of knowledge, it must be experienced, and experience is structured by our minds—both space and time being the forms of our intuition, "anschauung" in German, (for Kant, intuition is the process of sensing or the act of having a sensation)[12] or perception, and the unifying, structuring activity of our concepts. These aspects of mind turn the manifold of intuition, which arises by being affected by things-in-themselves, into the world of experience. But that does not bring the thing-in-itself into the world of experience. We do not cognize the thing-in-itself; we cognize the appearances that arise from being affected by it. In the sequent "If A is X then B is Y," A is the thing-in-itself. X is what Kant refers to as something akin to an attribute whereby the thing-in-itself is capable of affecting our sensibility. B is one of us. And Y is a manifold of sensibility. A and X are not appearances. So, they are not structured by space and time, which are our modes of intuition. They are, therefore, not subject to determinate judgment, or cognition. The antecedent is, therefore, not capable of being cognized. Thus the entire sequent cannot be cognized even though we routinely cognize the consequent: B is Y; that is, we routinely make determinate judgments about our manifolds of intuition. So, although the entire sequent must be thought for Kant's system to get off the ground, this thought is not, and never will be, capable of being a cognition, or determinate judgment. The antecedent can and must be thought of as a "real ground" (consistent with the pure category of real ground/real affect), but cannot be cognized as a cause (consistent with the schematized category of cause/effect). Thus, the thing-in-itself remains "unknowable."

According to Kant, the transcendental ego — the "Transcendental Unity of Apperception" — is similarly unknowable. Kant contrasts the transcendental ego to the empirical ego, the active individual self subject to immediate introspection. One is aware that there is an "I," a subject or self that accompanies one's experience and consciousness. Since one experiences it as it manifests itself in time, which Kant proposes is a subjective form of perception, one can know it only indirectly: as object, rather than subject. It is the empirical ego that distinguishes one person from another providing each with a definite character.[13]

Critique of Pure Reason Contents

The Critique of Pure Reason is arranged around several basic distinctions. After the two Prefaces (the A edition Preface of 1781 and the B edition Preface of 1787) and the Introduction, the book is divided into the Doctrine of Elements and the Doctrine of Method:

The Doctrine of Elements sets out the a priori products of the mind, and the correct and incorrect use of these presentations. Kant further divides the Doctrine of Elements into the Transcendental Aesthetic and the Transcendental Logic, reflecting his basic distinction between sensibility and the understanding. In the Transcendental Aesthetic he argues that space and time are pure forms of intuition inherent in our faculty of sense. The Transcendental Logic is separated into the Transcendental Analytic and the Transcendental Dialectic:

  • The Transcendental Analytic sets forth the appropriate uses of a priori concepts, called the categories, and other principles of the understanding, as conditions of the possibility of a science of metaphysics. The section titled the Metaphysical Deduction considers the origin of the categories. In the Transcendental Deduction, Kant then shows the application of the categories to experience. Next, the Analytic of Principles sets out arguments for the relation of the categories to metaphysical principles. This section begins with the Schematism, which describes how the imagination can apply pure concepts to the object given in sense perception. Next are arguments relating the a priori principles with the schematized categories.
  • The Transcendental Dialectic describes the transcendental illusion behind the misuse of these principles in attempts to apply them to realms beyond sense experience. Kant’s most significant arguments are the Paralogisms of Pure Reason, the Antinomy of Pure Reason, and the Ideal of Pure Reason, aimed against, respectively, traditional theories of the soul, the universe as a whole, and the existence of God. In the Appendix to the Critique of Speculative Theology Kant describes the role of the transcendental ideas of reason.

The Doctrine of Method contains four sections. The first section, Discipline of Pure Reason, compares mathematical and logical methods of proof, and the second section, Canon of Pure Reason, distinguishes theoretical from practical reason.

The Divisions of Critique of Pure Reason


1. First and second Prefaces
2. Introduction
3. Transcendental Doctrine of Elements
A. Transcendental Aesthetic
B. Transcendental Logic
(1) Transcendental Analytic
a. Analytic of Concepts
i. Metaphysical Deduction
ii. Transcendental Deduction
b. Analytic of Principles
i. Schematism (bridging chapter)
ii. System of Principles of Pure Understanding
a. Axioms of Intuition
b. Anticipations of Perception
c. Analogies of Experience
d. Postulates of Empirical Thought (Refutation of Idealism)
iii. Ground of Distinction of Objects into Phenomena and Noumena
iv. Appendix on the Amphiboly of the Concepts of Reflection
(2) Transcendental Dialectic: Transcendental Illusion
a. Paralogisms of Pure Reason
b. Antinomy of Pure Reason
c. Ideal of Pure Reason
d. Appendix to Critique of Speculative Theology
4. Transcendental Doctrine of Method
A. Discipline of Pure Reason
B. Canon of Pure Reason
C. Architectonic of Pure Reason
D. History of Pure Reason

Table of Contents

The Critique of Pure Reason represents an almost insurmountable barrier for a reader who is not familiar with Western Philosophy but an even greater hurdle in reading the book successfully is the way its content is arranged.

Critique of Pure Reason
Transcendental Doctrine of Elements Transcendental Doctrine of Method
First Part: Transcendental Aesthetic Second Part: Transcendental Logic Discipline of Pure Reason Canon of Pure Reason Architectonic of Pure Reason History of Pure Reason
Transcendental Doctrine of Elements
First Part: Transcendental Aesthetic Second Part: Transcendental Logic
Space Time First Division: Transcendental Analytic Second Division: Transcendental Dialectic
First Division: Transcendental Analytic
Book I: Analytic of Concepts Book II: Analytic of Principles
Clue to the discovery of all pure concepts of the understanding Deductions of the pure concepts of the understanding Schematism System of all principles Phenomena and Noumena
Second Division: Transcendental Dialectic
Transcendental Illusion Pure Illusion as the Seat of Transcendental Illusion
Book I: Concept of Pure Reason Book II: Dialectical Inferences of Pure Reason
Book II: Dialectical Inferences of Pure Reason
Paralogisms (Psychology) Antinomies (Cosmology) The Ideal (Theology)


I. Transcendental Doctrine of Elements

Transcendental Aesthetic

Kant's Transcendental Aesthetic deals with sensibility and with objects as far as they can be perceived, the word aesthetic being derived from the Greek root "aesthesis" meaning capable of sense perception. However, Kant's discussion of space and time in the Transcendental Aesthetic is introduced by his analysis of cognition, which presents an unfamiliar philosophical terminology.[15]

Following Alexander Baumgarten, Kant held that there are two kinds of knowledge: sensible (sensual) and logical. Sensible knowledge is based on sensation; logical knowledge is based on reason. Kant's division of Transcendental Aesthetic and Transcendental Logic result from these two kinds of knowledge. The Transcendental Aesthetic is that part of the Critique of Pure Reason that considers the contribution of sensation to cognition.

Kant distinguished between the matter and the form of appearances. The matter is "that in the appearance that corresponds to sensation" (A20/B34). The form is "that which so determines the manifold of appearance that it allows of being ordered in certain relations" (A20/B34). Kant's revolutionary claim is that the form of appearances — which he later identifies as space and time — is a contribution made by the faculty of sensation to cognition, rather than something that exists independently of the mind. This is the thrust of Kant's doctrine of the transcendental ideality of space and time.

Kant is attempting to understand the nature of a "sensible intuitor." A sensible intuitor must be affected by objects other-than-themselves in order for experience to arise. This is contrasted with an intellectual intuitor, which is what God would be. God produces the object-to-be-known, where-as a sensible intuitor must be presented with the object from a source other-than-itself. The contrast between a sensible intuitor and an intellectual intuitor is frequently invoked by Kant in order to limit the scope of certain conclusions he draws. But a further contrast is made in considering the possibility of sensible intuitor that may, at least hypothetically, exist and who differs from us. But differs in what way?

Philosophy, for Kant, begins with reflection upon experience. There seems to be two aspects of our experience (as sensible intuitors) that are highly relevant at this point. 1) Our manifolds of intuition are not static—they are constantly changing. To use an ancient phrase, they are in flux. 2) The contents of our manifolds of intuition are not in mere logical relation to each other but stand in some type of real, external relation to each other and to us. As epistemic agents capable of cognizing our manifolds of intuition, sensible intuitors must be have certain representations at their disposal—they be must bring these to experience in order to have experience. 1) They are in need of a representation of processuality [selecting a term that is deliberately odd with the hope that it does not invoke temporal connotations]. And 2) they are need of a representation of external relatedness [a term that likely invokes some connotation of space, but which the reader must actively suppress.] Kant's position throughout the Transcendental Aesthetic contains two persistent themes: A) WE are in possession of both 1) a representation of proccessuality; we call it Time, and the science of that representation is called Arithmetic: the science of the successive addition of homogenous unit to homogenous unit; and 2) WE are in possession of a representation of external relatedness; we call it Space; and the science of that representation is called Geometry; and B) there may be other sensible intuitors who possess alternative representations of processuality and external relatedness. We can say nothing in the affirmative as to the nature of these alternative representations—we can only invoke the single negative assertions: their representation of proccesuality is not Time; and their representation of external relatedness is not Space.

Certain conclusions that Kant draws during the Transcendental Deduction apply to sensible intuitors in general. That is, they would apply to any epistemic agent that is affected by mind-independent objects that gives rise to manifolds of sensible intuition within them. And it would not matter if they have Time and Space as the representations that fulfill their epistemic needs or not. As Kant moves toward the schematism in the latter parts of the Transcendental Deduction, the arguments he makes, and the conclusions he draws, are limited to spatial-temporal intuitors.

A consequence of this view is that spatial and temporal predicates are determinations that pertain to objects as appearances only—that is, they pertain to experience as we structure it through our modes of intuition. Other sensible intuitors would have other sets of predicates that pertain to their experience. And thing-in-themselves would be as indifferent to our spatial and temporal predicates and they are to the sets of predicates that other sensible intuitors deploy. Furthermore, God, who is not a sensible intuitor at all, and has no need of any representation of processuality or external relatedness, since these are aspects of a sensible intuitor's epistemic apparatus, would not require spatial or temporal predicates to cognize objects-as-they-are-in-themselves. So things-in-themselves are not spatial or temporal—which does not entail that they are not undergoing process and standing in real external relation to each other. It simply means that the predicates that form parts our determinate judgments, or cognitions, do not belong to the things-considered-in-themselves and independent of our mode of sensibility. In other words, our spatial and temporal predicates have no privileged status. Apart from our cognitive apparatus, we are in no position to indicate how space and time can have sense and meaning.

Kant's arguments for this conclusion are widely debated among Kant scholars. Some see the argument as based on Kant's conclusions that our representation of space and time are a priori intuitions. From here Kant is thought to argue that our representation of space and time as a priori intuitions entails that space and time are transcendentally ideal. This conclusion follows when the a priority of Space and time are linked to the hypothetical "other sensible intuitions." For spatial and temporal predicates mean nothing to them, and their analogue predicates mean nothing to us. Each set of predicates only function as determinations within their own cognitive apparatus. It is undeniable from Kant's point of view that in Transcendental Philosophy, the difference of things as they appear and things as they are is a major philosophical discovery.[16] Others see the argument as based upon the question of whether synthetic a priori judgments are possible. Kant is taken to argue that the only way synthetic a priori judgments, such as those made in geometry, are possible is if space is transcendentally ideal. This is the argument he deployed in the Prolegomena to Any Future Metaphysics. In that work, which uses argument by analytic method, one need only show that there is a logical relation between a priori synthetic judgments in Geometry and space being an a priori representation. Thus, if you accept that Geometry contains a priori synthetic judgments, you are strapped with the conclusion that space is an a priori representation. Kant erroneously includes this argument in the B edition of the first Critique's transcendental exposition of space. The arguments there should be limited to definitive reasons to take space as being a non-discursive, singular concept of a priori origin. From which, it would follow, along with the hypothesis of other sensible intuitors, that the only condition under which space and time have meaning (i.e., function in determinate judgments) is when they are applied to experience by spatial/temporal intuitors; i.e., they have no meaning apart from the constitution of our senses..

In Section I (Of Space) of Transcendental Aesthetic in the Critique of Pure Reason Kant poses the following questions: What then are time and space? Are they real existences? Or, are they merely relations or determinations of things, such, however, as would equally belong to these things in themselves, though they should never become objects of intuition; or, are they such as belong only to the form of intuition, and consequently to the subjective constitution of the mind, without which these predicates of time and space could not be attached to any object?[17] The answer that space and time are real existences belongs to Newton. The answer that space and time are merely relations or determinations of things even when they are not being sensed belongs to Leibniz. Both answers maintain that space and time exist independently of the subject's awareness. This is exactly what Kant denies in his answer that space and time belong to the subjective constitution of the mind.[18]

Space and time

Kant gives two expositions of space and time: metaphysical and transcendental. The metaphysical expositions of space and time are concerned with clarifying how those intuitions are known independently of experience. The transcendental expositions attempt to show how the metaphysical conclusions might be applied to enrich our understanding.

In the transcendental exposition, Kant refers back to his metaphysical exposition in order to show that the sciences would be impossible if space and time were not kinds of pure a priori intuitions. He asks the reader to take the proposition, "two straight lines can neither contain any space nor, consequently, form a figure", and then to try to derive this proposition from the concepts of a straight line and the number two. He concludes that it is simply impossible (A47-48/B65). Thus, as we cannot obtain this information from analytic reasoning; so it must be by way of synthetic reasoning, i.e., a synthesis of concepts (in this case two and straightness) with the pure (a priori) intuition of space. In other words, the concept that two straight lines cannot enclose a space does not follow from the mere logical relations obtain between the concepts two, line, straight and space. Rather, it follows from the real relation that holds between the things that those concepts stand for. Thus a real relation between two straight lines must be constructed in order that it can become apparent that no thing that answers to the concept "enclosed space" can ever arise from the real relation of the two straight lines.

But in this case, it was not experience that furnished the third term; otherwise, we would lose the necessary and universal character of geometry. Only space, which is a pure a priori form of intuition, can make this synthetic judgment, thus it must then be a priori. If geometry doesn't serve this pure a priori intuition, it is empirical, and would be an experimental science. But geometry doesn't proceed by measurements—it proceeds by demonstrations.

Kant rests his demonstration of the a priority of space on the example of geometry. He reasons that therefore if something exists, it needs to be intelligible. If we attacked this argument, we would doubt the universality of geometry (which no honest person would do, in Kant's estimation).

The other part of the Transcendental Aesthetic argues that time is a pure a priori intuition that renders mathematics possible. Time is not a general, or discursive, concept, since otherwise it would merely conform to formal logical analysis (and therefore, to the principle of non-contradiction). However, time makes it possible to deviate from the principle of non-contradiction: indeed, it is possible to say that A and non-A are in the same spatial location if one considers them in different times, and a sufficient alteration between states were to occur (A32/B48). Time and space cannot thus be regarded as existing in themselves. They are a priori forms of sensible intuition.

The current interpretation of Kant states that the subject inherently possesses the underlying conditions to perceive spatial and temporal presentations. The Kantian thesis claims that in order for the subject to have any experience at all, then it must be bounded by these forms of presentations (Vorstellung). Some scholars have offered this position as an example of psychological nativism, as a rebuke to some aspects of classical empiricism.

Kant's thesis concerning the transcendental ideality of space and time limits appearances to the forms of sensibility—indeed, they form the limits within which these appearances can count as sensible; and it necessarily implies that the thing-in-itself is neither limited by them nor can it take the form of an appearance within us apart from the bounds of sensibility (A48-49/B66). Yet the thing-in-itself is held by Kant to be the cause of that which appears, and this is where the paradox of Kantian critique resides: while we are prohibited from absolute knowledge of the thing-in-itself, we can impute to it a cause beyond ourselves as a source of representations within us.

[We should not impute to it a "cause." A cause is a temporally determined real ground. We impute to it a "real ground," but not a temporally determined one. Another sensible intutitor would likewise impute to it a real ground. Neither we, nor they, can form a determinate judgment, or cognition, of it as a real ground. Thus, it is not a "cause' for us. And it does not correspond to the other sensible intuitor's analogue of a cause either. For each of us, it must be thought of as a real ground and nothing more. As Kant says, although it is uncognizable, it must allow of being thought.]

Kant's view of space and time reject both the space and time of Aristotelian physics and the space and time of Newtonian physics. In the twentieth century, about a century after the publication of the Critique of Pure Reason, Albert Einstein would introduce a new concept of space and time with the Theory of Relativity. Space and time are no longer space and time but space-time. According to Bertrand Russell, "... That is, from a philosophical and imaginative point of view, perhaps the most important of all the novelties that Einstein introduced." On the other hand, some people would readily assume that Einstein's findings in Physics support the Kantian view of space and time. However, Russell is explicitly clear in stating that it is misleading to believe that Einstein's space-time in any way resembles Kant's space and time.[19]

Transcendental Logic

In the Transcendental Logic, one finds a section (titled The Refutation of Idealism) from Kant that frees his doctrine from any vestiges of subjective idealism, which would either doubt or deny the existence of external objects (B274-79). However, Senderowics warns that "... If the Refutation of Idealism indeed addresses a question left unanswered by the previous parts of the Critique of Pure Reason, Kant's preceding comments contain a gap that needs to be bridged."[20] Kant's distinction between the appearance and the thing-in-itself is not intended to imply that nothing knowable exists apart from consciousness, as with subjective idealism. Rather, it declares that knowledge is limited to phenomena as objects of a sensible intuition. In the Fourth Paralogism ("... A Paralogism is a logical fallacy."),[21] Kant further certifies his philosophy as distinct from that of subjective idealism by defining his position as a transcendental idealism in accord with empirical realism (A366-80). "The Paralogisms of Pure Reason" is the only chapter of the Dialectic that Kant rewrote for the second edition of the Critique of Pure Reason. In the first edition, the Fourth Paralogism offers a defence of Transcendental Idealism, which Kant reconsidered and relocated in the second edition.[22]

The Transcendental Logic is that part of the Critique where Kant investigates the understanding and its role in constituting our knowledge. The understanding is defined as the faculty of the mind that deals with concepts (A51-52/B75-76). The Logic is divided into two parts: the Analytic and the Dialectic. In the Analytic, Kant investigates the contributions of the understanding to knowledge. In the Dialectic, Kant investigates the limits of the understanding.

The idea of a transcendental logic is that of a logic that gives an account of the origins of our knowledge as well as its relationship to objects. This is contrasted by Kant with the idea of a general logic, which abstracts from the conditions under which our knowledge is acquired, and from any relation that knowledge has to objects. According to Helge Svare "... It is important to keep in mind what Kant says here about logic in general, and transcendental logic in particular, being the product of abstraction, so that we are not misled when a few pages later he emphasizes the pure, non-empirical character of the transcendental concepts or the categories.[23]

Kant's investigation resulted in his claim that the real world of experience can only be an appearance or phenomenon. What things are in themselves, or, other than being appearances, are completely unknowable by any animal or human mind.

First Division: Transcendental Analytic

The Transcendental Analytic is divided into an Analytic of Concepts and an Analytic of Principles, as well as a third section concerned with the distinction between phenomena and noumena. In Chapter III (Of the ground of the division of all objects into phenomena and noumena) of the Transcendental Analytic, Kant generalizes the implications of the Analytic in regard to transcendent objects preparing the way for the explanation in the Dialectics about thoughts of transcendent objects, Kant's detailed theory of the content and origin of our thoughts about specific transcendent objects.[24] The main sections of the Analytic of Concepts are The Metaphysical Deduction and The Transcendental Deduction of the Categories. The main sections of the Analytic of Principles are the Schematism, Axioms of Intuition, Anticipations of Perception, Analogies of Experience, Postulates and follow the same recurring tabular form:


Followed by the Refutation of Idealism (added in the 2nd edition).

The Metaphysical Deduction

Here Kant aims to derive the twelve pure concepts of the understanding (which he also calls "categories") from the logical forms of judgment. Kant arranges the forms of judgment in a table of judgments, which he uses to guide the derivation of the table of categories.[25]

He creates a list of categories by first enumerating the forms of possible objective judgment, which are endowed with their objectivity by virtue of their inherent a priori concepts. Kant claims that if we can identify all of the possible forms of objective judgment, we can then hope to use them as the basis to discover all of the most general concepts or categories that are employed in making such judgments, and thus that are employed in any cognition of objects.[25]

Now, the logicians have concerned themselves to ascertain and classify the various possible logical forms of judgments. Kant, accepts and adopts, with one or two modifications, their work as correct and complete, and lays before his reader, accordingly, the following table of the different logical forms of judgment, reduced under four heads:

1.Quantity of Judgements

In each of these ‘moments’ of judgment, there are three alternative classifications;(A70/B95).

1.Quantity of Judgements
  • Universal
  • Particular
  • Singular
  • Affirmative
  • Negative
  • Infinite
  • Categorical
  • Hypothetical
  • Disjunctive
  • Problematic
  • Assertoric
  • Apodeictic

The three relational forms are, in an important sense, the most basic, with the categorical form being the most basic of these, where one thinks the relation of logical subject to logical predicate: A is X. The hypothetical judgment form is a combination of two categorical judgments thought in the relation of logical ground to logical consequent: If A is X, then B is Y. And the disjunctive judgment form is a combination of two or more categorical judgments thought in relation of logical mutual opposition, or mutual logical determination: Either A is X or B is Y or C is Z etc... The disjuncts must be regarded as "exclusive" in the modern usage; If A is X then B is not Y and C is not Z etc...; Only one of the disjuncts is true and therefore they logically determine each other.

The various moments under the other three heading pertain to categorical judgments only. For any logical relation "A is X" we can think either: All A's are X; Some A's are X; or This A is an X. Likewise, we can think A is X; A is not X; or A is non-X. And, finally, we can think A's are possibly X; A's are actually X; or A's are necessarily X.

Through these various "moments of thought" we can think quite complicated logical relations: Either all A's are necessarily X or Some B's are possibly Y or This C is actually Z, for one example.

Kant points out that the modality of the judgment form adds nothing to the content of the judgment. It merely expresses the relationship that the judgment has to reason in general: it stands in either possible, actual or necessary relation to reason. The content of the judgment is determined entirely by the moments of Relation, Quantity and Quality of the judgment.

Kant's deviations from the standard Aristotelian syllogistic are not insignificant. For example, he admits that within standard logic there is no real need to distinguish between the Affirmative, Negative and Infinite judgment forms. Either a predicate belongs to a subject or it does not. "A is X" and "A is not X" suffice to express these two possibilities. "A is non-X" is an alternative way to express the fact that the predicate that belongs to A is not X but some other predicate—a non-X predicate. Kant says that logically, "A is non-X" is an Affirmative judgment, since it affirms the predicate term (non-X) of the subject term A. On the hand, it denies that the concept X belongs to the concept A as its predicate, which suggests that it is actually a Negative judgment. So there is a tension involved between thinking of judgments as expressing relations between subject terms and predicate terms and thinking of judgments as expressing relations between two concepts. Kant does not adequately address this tension when he opts for reducing the Infinite judgment form to an Affirmative judgment within standard logic.

Kant claims the Affirmative, Negative and Infinite trichotomy only becomes significant in transcendental logic. But since the table of judgments is supposed to be the clue to the discovery of the table of categories he has opened himself to the charge that the table of judgments is doctored in order to produce a pre-conceived set of categories, making the categories the "clue to the discovery of the judgment forms!"

Any possible defense from this charge must rely heavily upon the exact relation that holds between the two tables. And the exact relationship is one of the least settled issues in Kant scholarship. What is generally agreed upon is that the following crucial passage of the Metaphysical Deduction is the key to any interpretation of the two tables and their relation to each other:

"The same function of which gives unity to the various representations in a judgment also gives unity to the mere synthesis of various representations in an intuition, and this unity, in its most general expression, we entitle the pure concept of the understanding. The same understanding, through the same operations by which in concepts, by means of analytic unity, it produced the logical form of a judgment, also introduces a transcendental content into its representations, by means of synthetic unity of the manifold of intuition in general. On this account we are entitled to call these representations pure concepts of the understanding, and to regard them as applying a priori to objects—a conclusion which general logic is not in a position to establish. In this manner there arise precisely the same number of pure concepts of the understanding which -apply a priori to objects of intuition in general, as, in the preceding table, there have been found to be logical functions in all possible judgments."

Two of the issues this passage raises is 1) Is there a single transcendental content that accounts for the differences in the two tables or does each judgment form/category pair have its own transcendental content?; and 2) Which table is truly more fundamental? If the categories provide transcendental content and that content is what provides unity in both the synthetic unity of intuition and the logical unity in concepts, then the Table of Categories has be the foundation of the system and not the Table of Judgment Forms.

Both questions are crucially important. If there is only one transcendental content that accounts for the transition from The Table of Judgments to the Table of Categories then a defense of the introduction of that transcendental content by the understanding would suffice to defend the entire Table of Categories as a whole. On the other hand, if each category has its own transcendental content, then it is not easy to see how the defence of The Table of Categories could not occur except by defending each category separately. Within the Transcendental Deduction proper, Kant only invokes the categories of Real Subject/ Real Predicate and Real Ground/Real Consequent occasionally. And it is clear that in each instance he is using either Locke or Hume as examples of particular issues that are currently under consideration and he is not attempting the Deduction of either category in these instances. Commentators note this fact and conclude that the "real defense" of the categories must then be found in The Principles, which follows the Deduction proper and the Schematism. And it is difficult to explain how Kant could be that much in error as to where the Deduction or defense of the categories occurs, because he clearly indicates in the B edition that the main defence is complete in section 20, and bolstered by a significant additional conclusion in section 26, both of which are long before the Schematism or the Principles.

No summary account of the Critique of Pure Reason can avoid making commitments on these issues at this point. Because all further interpretation depends on how one answers these questions. In the intrepation that follows a defense will made for the claim that there is only one transcendental content, and with respect to the priority of the two tables, when the actual order of experience is considered, the Table of Categories is more fundamental, but in the order of exposition, given Kant's philosophical milieu, presenting the Table of Judgments as the foundation of the Table of categories is reasonable and justifiable.transcendental aesthetics

Both issues depend heavily on the distinction between Analytic and Synthetic judgments, which is an issue Kant inadequately addresses in the introduction to the first Critique. He does a better job in his response to J. A. Eberhard's critique of his transcendental idealism, which is translated and commented upon by Henry Allison in his book The Kant-Eberhard Controversy. There, Allison notes that the distinction is not merely one between judgments where the predicate term is already thought within the subject term and those where it is not. This characterization fails to indicate what relation does obtain between the subject term and the predicate term in non-analytic (i.e., synthetic judgments). And, in any case, it would only apply to judgments of the categorical form. Instead, Kant makes it clear that analytic judgments concern the logical relations among the concepts within the judgment, whereas, synthetic judgments concern the real relations between the things that the concepts stand for.

"All bachelors are unmarried" is almost universally intended as an analytic judgment. It is true as a mere consequence of the logical relations that obtain between the concepts of "bachelor and "unmarried." "All dogs in my household weigh between 2 and 80 pounds," can only be reasonably regarded as a synthetic judgment. If it is true, it must be true as a consequence of the real relations that hold between things that answer to the concept "dogs in my household," "things that weigh more than 2 pounds," and "things that weigh less than 80 pounds." For some assertions it is not always clear whether the judgment is analytic or synthetic. Which type of judgment is intended may turn on the speaker's definitions of the terms used within the judgment and whether they have what others might regard as rather unusual or stipulated definitions for their terms. There is nothing in mere grammar that can't mark off analytic judgments from synthetic judgments. If the truth is expected to follow from the logical relation among the concepts that are involved, then it is analytic—even if it turns out to be false because the expected logical relation does not actually pertain. And if the truth is expected to follow from the real relations among the things the concepts stand for then the assertion is synthetic. A person who excitedly rushes into a building repeating claiming "Unicorns do have one horn," Unicorns do have one horn," is not attempting an analytic judgment. It may be a clumsy way to do it, but the person is attempting to inform others that there is a real relation between unicorns and things with one horn. Despite his assertion's ability to be reduced to "Unicorns have one Horn' in general logic, he is clearly not this excited over a logical relation among concepts- one that everyone is undoubtedly already familiar with. His utterances need to be taken as synthetic—there is a real relation between white horse-like creatures and one-horned beings.

Eberhard claimed, in general, that anything Kant had right was already to be found in the Leibnizian-Wollfian system, and anything that Kant had that was not in that system was simply wrong. In particular, Eberhard claimed that the Analytic/Synthetic distinction could be found within the Leibnizian-Wollfian system. Kant vehemently denies this, going so far as to as say that that system could not even articulate the problem that Kant poses in his introduction: How are Synthetic Judgments Possible A Priori? Understanding why Kant claims this will contribute to an understanding of the similarities and difference between the Table of Judgments and the Table of Categories.

In Kant's view, every judgment in the Leibnizian-Wollfian system is, in principle, an analytic judgment! A being that could obtain to a complete concept of any given monad would be able to spin out the entire history of that monad, and every judgment would be nothing more that a logical relation between the subject term (a very complicated complete concept of the monad) and a predicate term (which would be a partial list of the predicates in the complete concept).

Unfortunately for us, God is the only being with sufficient intellectual capacity to perform these feats. God always has clear and distinct concepts. We only occasionally have clear and distinct concepts. Thus, we only occasionally can utter clear and distinct analytic judgments. Most of our concepts remain confused. A judgments based on confused concepts would be confused analytic judgments. But for Kant, this means that within Leibniz's system there are two species of analytic judgments. Those that are clear and distinct and those that are confused. The system does not contemplate two radically different types of judgments: those that are analytic and those that are synthetic. The Leinizian-Wollfian cannot define a synthetic judgment in Kant's sense and therefore cannot raise the question of how some such judgments might be possible a priori.

The Table of Judgments in Kant's system, is all that a Leibnizian-Wollfian would ever need. It lays out the various modes in which concepts can stand in logical relation to each other. Monads are not in real relation to one another. They only stand in indirect relations to each other because all are contained within the mind of God. But Kant rejects this relation as a mere ideal relationship between monads. And thus the basic concepts of real relations have no home in the Leibnizian-Wollfian system. The basic issue what the categories are: the concepts of the real relations among things, gets brushed aside in Leibniz because all truth boils down, in principle, to logical relations among concepts.

Analytic judgments concern the logical relations among concepts. The Table of Judgments, therefore, is sufficient to sum up any system of analytic judgments. Synthetic judgments concern the real relations between the things that the concepts stand for. What characteristic difference, then, is there between an analytic judgment and a synthetic judgment? The answer is that a synthetic judgment requires the thought of thing-in-general or object-in-general. In the analytic judgment of the categorical judgment form, you have the relation between a logical subject and a logical predicate. If one thinks this relation with respect to an object-in-general one no longer has a mere logical subject with its logical predicate—one is thinking a real subject with its real predicate. Real/ subject/real predicate is a pure category of the understanding. It is a concept of an object in general, based upon the logical function of subject/predicate.

At this point one must pause in order to be far more careful than Kant actually was. Kant would likely say that we are thinking "substance and attribute," or at best he would say that we are thinking "the pure category of substance and attribute." But "substance" has temporal connotations for us that this first very abstract concept should not have. "Substance," to us, means something that endures through time Yet this first abstract concept of a real subject should be abstract enough that it applies to the hypothetical "other sensible intuitor" whose mode of inner intuition is not time but some other representation of processuality, (of which we can say nothing except that it is not the representation we call time). This calls for the term real subject/real predicate. Only when Kant is talking of the schematized category that has relation to our specific mode of inner intuition will this article use the phrase substance/attribute. Several confusions in Kant interpretation can avoided or minimialized by this distinction.

In the crucial passage in the Metaphysical Deduction Kant mentioned a transcendental content. We must now tackle that notion. Locke attempted to found an empiricist epistemology on the concept of substance (i.e., the schematized category of real subject/real predicate.) He himself admits over and over again that no matter how much we investigate, no matter how keen our sense become, and no matter how much we learn to augment our senses with instruments we might never come to a correct conception of any substance. The good Bishop Berkeley interprets this as Locke's admission that we have no empirical contact with any substance. Thus, as a good empiricists, we must jettison the concept of substance altogether and become idealists: there is nothing but minds and the sensations they have.

Kant's diagnosis, which he repeats numerous times and in a variety of ways, is that the concept of substance has a transcendental origin, and an empirical deduction of it simply cannot justify its employment in any philosophical system. If we abstract from the temporal connotations of substance (which are valid only for us as temporal intuitors) we have the pure category of real subject/real predicate. This concept differs from the concept of logical subject/logical predicate in only one respect: it includes the concept of an object-in-general or, thing-in-general; it is thought about things and their real relations and not mere thought about concepts and their logical relations. The conclusion must be that the thought of an object-in-general is the transcendental content that the understanding introduces in order to bring unity to a manifold of intuition in synthetic judgments.

The same case can be made with respect to "logical ground/logical consequence;" 'real ground/real consequent;" "cause/effect;" and Hume. In the Table of judgments we have the hypothetical judgment form, which is the relation of logical ground to logical consequent:e.g., If X is a bachelor X is unmarried. In the table of categories we think the logical function in relation to objects-in-general and we thereby "produce" the category of real ground/real consequent. (Kant,again, would say, at best, "the pure category of cause and effect." But once again, the word "cause" invokes temporal connotations that do not belong with the pure category. And Kant is very sloppy in distinguishing considerations of the pure category from the schematized category, which alone should allow any temporal connotations.) Hume was concerned to find a justification for the use of the schematized category cause/effect. Recognizing that the concept carried with it a sense of necessity that could not arise from empirical data, no matter how often the data re-occurred, and realizing that it wasn't merely true by definition that things that occur have causes, he concluded that no adequate justification for it use was available.

He then sought to explain why it is illegitimately used anyway. We observe that event A precedes event B; We observe this again and again and again on many occasions. He claimed that eventually when we merely think of event A we are naturally led to think of event B. And noting that event B now seems to necessarily follow event A we mistakenly take what at best has become a psychological necessity for an objective necessity—A causes B.

Kant's diagnosis for Hume is identical to his diagnosis for Locke. Abstracting from the temporal connotations of "cause' we have the pure concept of real ground/real effect, which differs from the concept of logical ground/logical effect only in regard to the thought of an object-in-general. The thought of an object-in-general is a transcendental content that the understanding introduces to give unity to the manifold of intuition. It is not abstracted from the empirical content of experience. Hume, then, was seeking an empirical deduction of a concept that needs a transcendental deduction because it includes a transcendental content.

The concept of a logical mutual determination, when thought of in relation to things or objects, becomes the concept of real mutual determination. Although the term "community" does not seem to carry the temporal connotations that "substance" and "cause" do, it would be good practice to drop the phrase "pure category of community" in favor of "real mutual determination." The schematized category should alone carry any name with possible temporal connotations; "influence" definitely suggests an affect over time, and should, thus, not be used in reference to the pure category, although that is the translation of the word Kant chose in German.

The other nine judgment forms and their corresponding categories can be dealt with more briefly now. There is, according to Kant, important distinctions between: logical universality and real universality; between logical particulars and real particulars; logical negation and real negation; logical possibility and real possibility; logical necessity and real necessity; and so on. He makes no attempt to provide separate nomenclature for the pure categories and their schematized counterparts here. Perhaps their failure to arise as specific philosophical problems as with "substance" and "cause" might explain the lack of a felt need for separate terms. The problems they give rise to are in Metaphysics and concerns their transcendental employment. "Substance" and "cause" struggled with their justifications in empirical employment, as witnessed by Locke and Hume.

Since we are in fact spatial/temporal intuitors most of our vocabulary is likely saturated with spatial and temporal connotations. Finding words that capture the distinction between the mere logical relations (judgment forms) and the real relations (categories) but which do not pre-suppose temporal connotations (as in the schematized categories) may be next to impossible in either German or in translation. The terms Kant chose, translated into English, for the pure categories are listed below:

1.Categories of Quantity
  • Unity
  • Plurality
  • Totality
2.Categories of Quality
  • Reality
  • Negation
  • Limitation
3.Categories of Relation
  • Inherence and Subsistence (substance and accident)
  • Causality and Dependence (cause and effect)
  • Community (reciprocity between agent and patient)
4.Categories of Modality
  • Possibility—Impossibility
  • Existence—Non-existence
  • Necessity—Contingency

These categories, then, are the fundamental, primary, or native conceptions of the understanding, which flow from, or constitute the mechanism of, its nature, are inseparable from its activity, and are therefore, for human thought, universal and necessary, or a priori. They are not contingent states or images of sensuous consciousness, and hence not to be thence derived. But they are not known to us independently of such consciousness or of sensible experience. On the one hand, they are exclusively involved in, and hence come to our knowledge exclusively through, the spontaneous activity of the understanding. But, on the other hand, the understanding is never active, until sensible data are furnished as material for it to act upon, and so it may truly be said that they become known to us "only on the occasion of sensible experience." For Kant, in opposition to Wolff and Hobbes, the categories exist only in the mind.[26]

These categories are "pure" conceptions of the understanding, in as much as they are independent of all that is contingent in sense. They are not derived from what is called the matter of sense, or from particular, variable sensations. But they are not independent of the universal and necessary form of sense. Again, Kant, in the "Transcendental Logic," is professedly engaged with the search for an answer to the second main question of the Critique, How is pure physical science, or sensible knowledge, possible? Kant, now, has said, and, with reference to the kind of knowledge mentioned in the foregoing question, has said truly, that thoughts, without the content which perception supplies, are empty. This is not less true of pure thoughts, than of any others. The content that the pure conceptions, as categories of pure physical science or sensible knowledge, cannot derive from the matter of sense, they must and do derive from its pure form. And in this relation between the pure conceptions of the understanding and their pure content there is involved, as we shall see, the most intimate community of nature and origin between sense, on its formal side (space and time), and the understanding itself. For Kant, space and time are a priori intuitions. Out of a total of six arguments in favor of space as a priori intuition, Kant presents four of them in the Metaphysical Exposition of space: two argue for space a priori and two for space as intuition.[27]

Philosophy begins with reflection on experience. The task of the philosopher is to carefully tease apart the various components of experience and assign each to its correct origin. Experience for us is experience of spatially and temporally ordered objects with a multitude of empirical predicates that belong to each. Thoughts of objects-in-general are what Kant means by "categories." Since experience precedes philosophy and the categories make experience possible the categories are primary. Even in the order of reflection the categories are primary. We do not reach the logical functions of judgment without abstracting away the reference to any object. Reference to objects is, necessarily, reference to categorical thought. The logical functions of judgment would not have become enumerated in general logic if transcendental logic were not already carrying out its function by rendering empirical experience coherent. And, only afterward do we discover the logical forms of judgment by abstracting all other elements that come together in experience, including the categories, qua concepts of objects-in-general.

But the Table of Judgments is the natural starting point for an exposition of the system. Aristotelian syllogistic had been accepted for 2000 years by the time Kant was writing. The stumbling block for Hume and Locke is the transcendental content, which is the last bit abstracted away before reaching the logical functions of judgment. And the problem with the entire Leibnizian-Wollfian system, in Kant's view, is that one crucial component of a system of epistemology (general logic), which needs to be re-synthesized with the other crucial components in a model of reason becomes the entire organon of the science of epistemology, rather than, as Kant says, a propaedeutic to the science. So the Table of Judgments is a relatively non-controversial starting point (aside from the amendations Kant introduces). Correctly amended by Kant, there are 12 judgment forms. Since a category is a judgment form from which the thought of an object-in-general has not been abstracted, there must be 12 categories.

Kant indicates that one principal purpose of a metaphysical deduction is to show that we are in possession of pure concepts. Since pure concepts cannot be derived from empirical experience and pure concepts involve concepts of strict necessity, there is really no issue at all that we are in possession of some pure concepts. The concept of a substance as an enduring ground of changing attributes and the concept of a cause as something through which something else (an effect) must necessarily arise are clearly pure concepts on this criteria. Kant's real achievement in the Metaphysical Deduction chapter is that he has provided what he takes to be a reason to believe that we possess 12 of these and not merely the two that Locke and Hume brought to keen focus.

In the preface to The Metaphysical Foundations of Natural Science Kant says:

"The table of categories completely contains all the pure concepts of the understanding as well as all the formal operations of the understanding in judgments, from which such pure concepts are derived and from which they also differ in nothing except that in the concept of the understanding, an object is thought as determined in regard to one or another of the functions of judgment."

A logical function of judgment can provide a "determination" of the thought of an object. Albeit, at this level, these "determinations" are actually quite indeterminate or abstract. The bare notion of something as being a real subject barely has a meaning. It is merely the form of a concept of an object as a real subject, and it does not actually contain any content yet. The content must wait upon the occasion of empirical experience.

A more determinate concept of an object-in-general would be the schematized category of real subject: substance. From the schematized category there arises a principle: Substances endure. This principle Kant calls a "pure cognition." It is, in one sense, a fully determinate judgment, so it can be called a cognition. But since it is a principle that does not rely on empirical data, it is pure. But Kant warns us that we are only entitled to call it a pure cognition because we are aware that it has necessary application to empirical experience. In the absence of this necessary application we would not know under what circumstance the pure principle could ever be given sense or meaning (sinn und bedeutung). And thus, it would fail have a determinate meaning, and thereby fail to be a fully determinate judgment, or cognition. So only in virtue of making empirical cognition possible is it entitled to be called a pure cognition.

There is a transition from the less determinate to the fully determinate (i.e., from mere thought to cognition (erkenntnis)), as we proceed from the bare thought "object;" to object as real subject; to object as substance; to this empirical substance; or from the bare thought "object;" to object as real ground; to object as cause; to this empirical cause.

Only the last, strictly speaking, is a cognition. Only empirical intuition can provide a fully determinate judgment ("erkenntnis" or "cognition"). The schematized category arises from the pure category by application of the pure intuition of time to the pure category. Because this procedure applies intuition to the mere thought of an object it exhibits the pure form' of cognition (or, more correctly, the principle that arises from the schematized category exhibits the pure form of cognition). Consequently, it is reasonable to call the principles of the understanding "pure cognitions" even though they are not, strictly speaking, fully determinate judgments as long as they lack empirical content.

The reason that traditional metaphysics must collapse in the face of this critique is that traditional metaphysics wished to employ the categories without reference to any even merely possible empirical intuition. In the absence of any reference to possible experience the mere thoughts being referred to lack what is needed in order for them to be fully determinate thoughts or fully determinate judgments; i.e., there is no hope of them being cognitions. And that is tantamount to saying that they lack the condition under which these mere thoughts can have actual meaning. This does not entail, however, that everything thought in traditional metaphysics is pointless or useless. Some thoughts may have legitimate use as regulative principles for theoretic reason. And others may find a home in practical cognition. The acts whereby a rational agent determines the intention of its own will requires concepts for guidance. God, freedom and immortality each play a role in this.

So, in summary, the Metaphysical Deduction's limited aim was demonstrate our possession of pure concepts of objects, (while indicating that there are twelve such concepts, based upon Kant's amendations to generally accepted logic. Beyond the two that could easily be identified (cause and substance) we learn that each pure concept is based upon a logical function. There being twelve logical functions, there must be twelve pure concepts or categories. The issue for philosophy is not our mere possession of these categories, but rather, our employment of them: by what right do we use these concepts. The right to use the concepts "cause" and "substance" (which are derived from the pure categories) has been seriously challenged by Hume and the philosophical criticisms of Locke's epistemology. The task of the Transcendental Deduction is to defend our use or employment of these concepts. Since the concepts arise as a group from the logical functions of judgments they can, in fact, be defended as a group. The categories arise by thinking the logical functions of judgment in relation to the thought of an object-in-general. This transcendental act of the understanding whereby it spontaneously thinks objects for possible intuition must be defended.

The "object" is not presented in the empirical contents of experience; it is spontaneously thought by the understanding as a means of giving unity to the empirical manifold of intuition that is given to a sensible intuitor. The epistemic need for a "vehicle" for the represented unity of the manifold of intuition will result from Kant's analysis of the possibility of the unity of consciousness in experience. Transcendental Apperception requires consciousness of the act unifying the manifold of intuition. And that, in turn, will require the thought of an object in general.

The Transcendental Deduction

In the Transcendental Deduction, Kant aims to show that the categories derived in the Metaphysical Deduction are conditions of all possible experience. He achieves this proof roughly by the following line of thought: all representations must have some common ground if they are to be the source of possible knowledge (because extracting knowledge from experience requires the ability to compare and contrast representations that may occur at different times or in different places), this ground of all experience is the self-consciousness of the experiencing subject, and the constitution of the subject is such that all thought is rule-governed in accordance with the categories. It follows that the categories feature as necessary components in any possible experience.[28]

1.Axioms of intuition
2.Anticipations of perception
3.Analogies of experience
4.Postulates of empirical thought in general
The Schematism

In order for any concept to have meaning, it must be related to sense perception. The 12 categories, or a priori concepts, are related to phenomenal appearances through schemata. Each category has a schema. It is a connection through time between the category, which is an a priori concept of the understanding, and a phenomenal a posteriori appearance. These schemata are needed to link the pure category to sensed phenomenal appearances because the categories are, as Kant says, heterogeneous with sense intuition. Categories and sensed phenomena, however, do share one characteristic: time. Succession is the form of sense impressions and also of the Category of causality. Therefore, time can be said to be the schema of Categories or pure concepts of the understanding. According to Heidegger, for Kant "... The schemata of pure concepts of understanding, the categories, are a priori time-determinations and as such they are a transcendental product of the pure power of imagination."[29]

The Refutation of Idealism

In order to answer criticisms of the Critique of Pure Reason that Transcendental Idealism denied the reality of external objects, Kant added a section to the second edition (1787) titled "The Refutation of Idealism" that turns the "game" of idealism against itself by arguing that self-consciousness presupposes external objects in space. Defining self-consciousness as a determination of the self in time, Kant argues that all determinations of time presuppose something permanent in perception and that this permanence cannot be in the self, since it is only through the permanence that one's existence in time can itself be determined. This argument inverted the supposed priority of inner over outer experience that had dominated philosophies of mind and knowledge since Descartes. In Book II, chapter II, section III of the Transcendental Analytic, right under "The Postulates of Empirical Thought", Kant adds his well known "Widerlegung des Idealismus" (Refutation of Idealism) where he refutes both Descartes' problematic idealism and Berkeley's dogmatic idealism. According to Kant, in problematic idealism the existence of objects is doubtful or impossible to prove while in dogmatic idealism, the existence of space and therefore of spatial objects is impossible. Kant holds that external objects may be directly perceived and that such experience is a necessary presupposition of self-consciousness.[30]

Appendix: Amphiboly of Concepts of Reflection
"Through observation and analysis of appearances we penetrate to nature's inner recesses, and no one can say how far this knowledge may in time extend. But with all this knowledge, and even if the whole of nature were revealed to us, we should still never be able to answer those transcendental questions which go beyond nature. The reason of this is that it is not given to us to observe our own mind with any other intuition than that of inner sense; and that it is yet precisely in the mind that the secret of the source of our sensibility is located. The relation of sensibility to an object and what the transcendental ground of this [objective] unity may be, are matters undoubtedly so deeply concealed that we, who after all know even ourselves only through inner sense and therefore as appearance, can never be justified in treating sensibility as being a suitable instrument of investigation for discovering anything save always still other appearances – eager as we yet are to explore their non-sensible cause." (A278/B334) As an Appendix to the First Division of Transcendental Logic, Kant intends the "Amphiboly of the Conceptions of Reflection" to be a critique of Leibniz's metaphysics and a prelude to Transcendental Dialectic, the Second Division of Transcendental Logic. Kant introduces a whole set of new ideas called "concepts of reflection": identity/difference, agreement/opposition, inner/outer and matter/form. According to Kant, the categories do have but these concepts have no synthetic function in experience. These special concepts just help to make comparisons between concepts judging them either different or the same, compatible or incompatible. It is this particular action of making a judgement that Kant calls "logical reflection."[31]

Second Division: Transcendental Dialectic

Following the systematic treatment of a priori knowledge given in the transcendental analytic, the transcendental dialectic seeks to dissect dialectical illusions. Its task is effectively to expose the fraudulence of non-empirical employment of the understanding. The Transcendental Dialectic shows how pure reason should not be used. According to Kant, the rational faculty is plagued with dialectic illusions as man attempts to know what can never be known.[32]

This longer but less dense section of the Critique is composed of five essential elements, as follows:

Introduction (to Reason and the Transcendental Ideas) Rational Psychology (the nature of the soul) Rational Cosmology (the nature of the world) Rational Theology (God) Appendix (on the constitutive and regulative uses of reason)

In the introduction, Kant introduces a new faculty, human reason, positing that it is a unifying faculty that unifies the manifold of knowledge gained by the understanding. Another way of thinking of reason is to say that it searches for the 'unconditioned'; Kant had shown in the Second Analogy that every empirical event has a cause, and thus each event is conditioned by something antecedent to it, which itself has its own condition, and so forth. Reason seeks to find an intellectual resting place that may bring the series of empirical conditions to a close, to obtain knowledge of an 'absolute totality' of conditions, thus becoming unconditioned. All in all, Kant ascribes to reason the faculty to understand and at the same time criticize the illusions it is subject to.[33]

The Paralogisms of Pure Reason

One of the ways that pure reason erroneously tries to operate beyond the limits of possible experience is when it thinks that there is an immortal Soul in every person. Its proofs, however, are paralogisms, or the results of false reasoning.

The Soul is substance

Every one of my thoughts and judgments is based on the presupposition "I think." "I" is the subject and the thoughts are the predicates. But I should not confuse the ever-present logical subject of my every thought with a permanent, immortal, real substance (soul). The logical subject is a mere idea, not a real substance. Unlike Descartes who believes that the soul may be known directly through reason, Kant asserts that no such thing is possible. Descartes declares cogito ergo sum but Kant denies that any knowledge of "I" may be possible. "I" is only the background of the field of apperception and as such lacks the experience of direct intuition that would make self-knowledge possible. This implies that the self in itself could never be known. Like Hume, Kant rejects knowledge of the "I" as substance. For Kant, the "I" that is taken to be the soul is purely logical and involves no intuitions. The "I" is the result of the a priori consciousness continuum not of direct intuition a posteriori. It is apperception as the principle of unity in the consciousness continuum that dictates the presence of "I" as a singular logical subject of all the representations of a single consciousness. Although "I" seems to refer to the same "I" all the time, it is not really a permanent feature but only the logical characteristic of a unified consciousness.[34]

The Soul is simple

The only use or advantage of asserting that the soul is simple is to differentiate it from matter and therefore prove that it is immortal. But the substratum of matter may also be simple. Since we know nothing of this substratum, both matter and soul may be fundamentally simple and therefore not different from each other. Then the soul may decay, as does matter. It makes no difference to say that the soul is simple and therefore immortal. Such a simple nature can never be known through experience. It has no objective validity. According to Descartes, the soul is indivisible. This paralogism mistakes the unity of apperception for the unity of an indivisible substance called the soul. It is a mistake that is the result of the first paralogism. It is impossible that thinking could be composite for if the thought by a single consciousness were to be distributed piecemeal among different consciousnesses, the thought would be lost. According to Kant, the most important part of this proposition is that a multi-faceted presentation requires a single subject. This paralogism misinterprets the metaphysical oneness of the subject by interpreting the unity of apperception as being indivisible and the soul simple as a result. According to Kant, the simplicity of the soul as Descartes believed cannot be inferred from the "I think" as it is assumed to be there in the first place. Therefore, it is a tautology.[35]

The Soul is a person

In order to have coherent thoughts, I must have an "I" that is not changing and that thinks the changing thoughts. But we can't prove that there is a permanent soul or an undying "I" that constitutes my person. I only know that I am one person during the time that I am conscious. As a subject who observes my own experiences, I attribute a certain identity to myself. But, to another observing subject, I am an object of his experience. He may attribute a different persisting identity to me. In the third paralogism, the "I" is a self-conscious person in a time continuum, which is the same as saying that personal identity is the result of an immaterial soul. The third paralogism mistakes the "I", as unit of apperception being the same all the time, with the everlasting soul. According to Kant, the thought of "I" accompanies every personal thought and it is this that gives the illusion of a permanent I. However, the permanence of "I" in the unity of apperception is not the permanence of substance. For Kant, permanence is a schema, the conceptual means of bringing intuitions under a category. The paralogism confuses the permanence of an object seen from without with the permanence of the "I" in a unity of apperception seen from within. From the oneness of the apperceptive "I" nothing may be deduced. The "I" itself shall always remain unknown. The only ground for knowledge is the intuition, the basis of sense experience.[36]

The Soul is separated from the experienced world

The soul is not separate from the world. They exist for us only in relation to each other. Whatever we know about the external world is only a direct, immediate, internal experience. The world appears, in the way that it appears, as a mental phenomenon. We cannot know the world as a thing-in-itself, that is, other than as an appearance within us. To think about the world as being totally separate from the soul is to think that a mere phenomenal appearance has independent existence outside of us. If we try to know an object as being other than an appearance, it can only be known as a phenomenal appearance, never otherwise. We cannot know a separate, thinking, non-material soul or a separate, non-thinking, material world because we cannot know things, as to what they may be by themselves, beyond being objects of our senses. The fourth paralogism is passed over lightly or not treated at all by commentators. In the first edition of the Critique of Pure Reason, the fourth paralogism is addressed to refuting the thesis that there is no certainty of the existence of the external world. In the second edition of the Critique of Pure Reason, the task at hand becomes the Refutation of Idealism. Sometimes, the fourth paralogism is taken as one of the most awkward of Kant's invented tetrads. Nevertheless, in the fourth paralogism, there is a great deal of philosophizing about the self that goes beyond the mere refutation of idealism. In both editions, Kant is trying to refute the same argument for the non-identity of mind and body.[37] In the first edition, Kant refutes the Cartesian doctrine that there is direct knowledge of inner states only and that knowledge of the external world is exclusively by inference. Kant claims mysticism is one of the characteristics of Platonism, the main source of dogmatic idealism. Kant explains skeptical idealism by developing a syllogism called "The Fourth Paralogism of the Ideality of Outer Relation:"

1) If that whose existence can be inferred only as a cause of given perceptions has only a doubtful existence.

2) And the existence of outer appearances cannot be immediately perceived but can be inferred only as the cause of given perceptions.

3) Then, the existence of all objects of outer sense is doubtful.[38]

Kant may have had in mind an argument by Descartes:

a) My own existence is not doubtful

b) But the existence of physical things is doubtful

c) Therefore, I am not a physical thing.

It is questionable that the fourth paralogism should appear in a chapter on the soul. What Kant implies about Descartes' argument in favor of the immaterial soul is that the argument rests upon a mistake on the nature of objective judgement not on any misconceptions about the soul. The attack is mislocated.[39]

These Paralogisms cannot be proven for speculative reason and therefore can give no certain knowledge about the Soul. However, they can be retained as a guide to human behavior. In this way, they are necessary and sufficient for practical purposes. In order for humans to behave properly, they can suppose that the soul is an imperishable substance, it is indestructibly simple, it stays the same forever, and it is separate from the decaying material world. On the other hand, anti-rationalist critics of Kant's ethics consider it too abstract, alienating, altruistic or detached from human concern to actually be able to guide human behavior. It is then that the Critique of Pure Reason offers the best defense, demonstrating that in human concern and behavior, the influence of rationality is preponderant.[40]

The Antinomy of Pure Reason

Kant presents the four antinomies of reason in the Critique of Pure Reason as going beyond the rational intention of reaching a conclusion. For Kant, an antinomy is a pair of faultless arguments in favor of opposite conclusions. Historically, Gottfried Leibniz and Samuel Clarke (Newton's spokesman) had just recently engaged in a titanic debate of unprecedented repercussions. Kant's formulation of the arguments was affected accordingly.[41]

The Ideas of Rational Cosmology are dialectical. They result in four kinds of opposing assertions, each of which is logically valid. The antinomy, with its resolution, is as follows:

Thesis: The world has, as to time and space, a beginning (limit). Antithesis: The world is, as to time and space, infinite. Both are false. The world is an object of experience. Neither statement is based on experience.

Thesis: Everything in the world consists of elements that are simple. Antithesis: There is no simple thing, but everything is composite. Both are false. Things are objects of experience. Neither statement is based on experience.

Thesis: There are in the world causes through freedom. Antithesis: There is no freedom, but all is nature. Both may be true. The thesis may be true of things-in-themselves (other than as they appear). The antithesis may be true of things as they appear.

Thesis: In the series of the world-causes there is some necessary being. Antithesis: There is nothing necessary in the world, but in this series all is contingent. Both may be true. The thesis may be true of things-in-themselves (other than as they appear). The antithesis may be true of things as they appear.

According to Kant, rationalism came to fruition by defending the thesis of each antinomy while empiricism evolved into new developments by working to better the arguments in favor of each antithesis.[42]

Pure Reason

Pure reason mistakenly goes beyond its relation to possible experience when it concludes that there is a Being who is the most real thing ("ens realissimum") conceivable. This "ens realissimum" is the philosophical origin of the idea of God. This personified object is postulated by Reason as the subject of all predicates, the sum total of all reality. Kant called this Supreme Being, or God, the Ideal of Pure Reason because it exists as the highest and most complete condition of the possibility of all objects, their original cause and their continual support. However, Kant's explication of the theological idea is notoriously unfathomable.[43]

Refutation of the Ontological Proof of God's Existence

The ontological proof can be traced back to Anselm of Canterbury (1033–1109). Anselm presented the proof in chapter 3 of a short treatise titled "Discourse on the existence of God." It was not Kant but the Scholastic Thomas Aquinas who first challenged the logical consistency of the proof. However, arguably, none have refuted the ontological proof more radically and thoroughly than Kant.[44]

The Ontological Proof considers the concept of the most real Being ("ens realissimum") and concludes that it is necessary. The Ontological Argument states that God exists because he is perfect. If he didn't exist, he would be less than perfect. Existence is assumed to be a predicate or attribute of the subject, God. But, Kant asserted that existence is not a predicate. Existence or Being is merely the infinitive of the copula or linking, connecting verb "is" in a declarative sentence. It connects the subject to a predicate. "Existence is evidently not a real predicate ... The small word is, is not an additional predicate, but only serves to put the predicate in relation to the subject." (A599) Also, we cannot accept a mere concept or mental idea as being a real, external thing or object. The Ontological Argument starts with a mere mental concept of a perfect God and tries to end with a real, existing God.

Summarized further, we may say that this argument is essentially deductive in nature. Given a certain fact, it proceeds to infer another from it. The method pursued, then, is that of deducing the fact of God's being from the a priori idea of him. If man finds that the idea of God is necessarily involved in his self-consciousness, it is legitimate for him to proceed from this notion to the actual existence of the divine being. In other words, the idea of God necessarily includes existence. It may include it in several ways. One may argue, for instance, according to the method of Descartes, and say that the conception of God could have originated only with the divine being himself, therefore the idea possessed by us is based on the prior existence of God himself. Or we may allege that we have the idea that God is the most necessary of all beings — that is to say, he belongs to the class of realities; consequently it cannot but be a fact that he exists. This is held to be proof per saltum. A leap takes place from the premise to the conclusion, and all intermediate steps are omitted. The implication is that premise and conclusion stand over against one another without any obvious, much less necessary, connection. A jump is made from thought to reality. Kant here objects that being or existence is not a mere attribute that may be added on to a subject, thereby increasing its qualitative content. The predicate, being, adds something to the subject that no mere quality can give. It informs us that the idea is not a mere conception, but is also an actually existing reality. Being, as Kant thinks, actually increases the concept itself in such a way as to transform it. You may attach as many attributes as you please to a concept; you do not thereby lift it out of the subjective sphere and render it actual. So you may pile attribute upon attribute on the conception of God, but at the end of the day you are not necessarily one step nearer his actual existence. So that when we say God exists, we do not simply attach a new attribute to our conception; we do far more than this implies. We pass our bare concept from the sphere of inner subjectivity to that of actuality. This is the great vice of the Ontological argument. The idea of ten dollars is different from the fact only in reality. In the same way the conception of God is different from the fact of his existence only in reality. When, accordingly, the Ontological proof declares that the latter is involved in the former, it puts forward nothing more than a mere statement. No proof is forthcoming precisely where proof is most required. We are not in a position to say that the idea of God includes existence, because it is of the very nature of ideas not to include existence.

Kant explains that being not being a predicate could not characterize a thing. Logically, it is the copula of a judgment. In the proposition, "God is almighty", the copula "is" does not add a new predicate; it only unites a predicate to a subject. To take God with all its predicates and say that "God is" is equivalent to "God exists" or that "There is a God" is to jump to a conclusion as no new predicate is being attached to God. The content of both subject and predicate is one and the same. According to Kant then, existence is not really a predicate. Therefore, there is really no connection between the idea of God and God's appearance or disappearance. No statement about God whatsoever may establish God's existence. Kant makes a distinction between "in intellectus" (in mind) and "in re" (in reality or in fact) so that questions of being are a priori and questions of existence are resolved a posteriori.[45]

Refutation of the Cosmological ("Prime Mover") Proof of God's Existence

The Cosmological Proof considers the concept of an absolutely necessary Being and concludes that it has the most reality. In this way, the Cosmological Proof is merely the converse of the Ontological Proof. But the Cosmological Proof purports to start from sense experience. It says, "If anything exists in the cosmos, then there must be an absolutely necessary Being. " It then claims that there is only one concept of an absolutely necessary object. That is the concept of a Supreme Being who has maximum reality. Only such a supremely real being would be necessary and independently sufficient without compare. But this is the Ontological Proof again, which was asserted a priori without sense experience.

Summarizing The Cosmological Argument further, it may be stated as follows: Contingent things exist — at least I exist; and as they are not self-caused, nor capable of explanation as an infinite series, it is requisite to infer that a necessary being, on whom they depend, exists. Seeing that this being exists, he belongs to the realm of reality. Seeing that all things issue from him, he is the most necessary of beings, for only a being who is self-dependent, who possesses all the conditions of reality within himself, could be the origin of contingent things. And such a being is God. This proof is invalid for three chief reasons. First, it makes use of a category, namely, Cause. And, as has been already pointed out, it is not possible to apply this, or any other, category except to the matter given by sense under the general conditions of space and time. If, then, we employ it in relation to Deity, we try to force its application in a sphere where it is useless, and incapable of affording any information. Once more, we are in the now familiar difficulty of the paralogism of Rational Psychology or of the Antinomies. The category has meaning only when applied to phenomena. But God is a noumenon. Second, it mistakes an idea of absolute necessity — an idea that is nothing more than an ideal — for a synthesis of elements in the phenomenal world or world of experience. This necessity is not an object of knowledge, derived from sensation and set in shape by the operation of categories. It cannot be regarded as more than an inference. Yet the cosmological argument treats it as if it were an object of knowledge exactly on the same level as perception of any thing or object in the course of experience. Thirdly, it presupposes the Ontological argument, already proved false. It does this, because it proceeds from the conception of the necessity of a certain being to the fact of his existence. And it is possible to take this course only if idea and fact are convertible with one another. It has just been proved that they are not so convertible.[46]

Physico-theological ("Watch Maker") Proof of God's Existence

The Physico-theological Proof of God's existence is supposed to be based on a posteriori sensed experience of nature and not on mere a priori abstract concepts. It observes that the objects in the world have been intentionally arranged with great wisdom. The fitness of this arrangement could never have occurred randomly, without purpose. The world must have been caused by an intelligent power. The unity of the relation between all of the parts of the world leads us to infer that there is only one cause of everything. That one cause is a perfect, mighty, wise, and self-sufficient Being. This physico-theology does not, however, prove with certainty the existence of God. For this, we need something absolutely necessary that consequently has all-embracing reality. But this is the Cosmological Proof, which concludes that an all-encompassing real Being has absolutely necessary existence. All three proofs can be reduced to the Ontological Proof, which tried to make an objective reality out of a subjective concept.

In the Critique of Pure Reason, Kant abandons the attempt to prove the existence of God although Kant's real intention is to attempt to disprove the non-existence of God. Rather than proving the existence of God, Kant is really trying to disprove the non-existence of God since no one can prove the non-existence of God. In abandoning any attempt to prove the existence of God, Kant declares the three proofs of rational theology known as the ontological, the cosmological and the physico-theological as quite untenable.[47]

II. Transcendental Doctrine of Method

The second book in the Critique, and by far the shorter of the two, attempts to lay out the formal conditions of the complete system of pure reason.

In the Transcendental Dialectic, Kant showed how pure reason is improperly used when it is not related to experience. In the Method of Transcendentalism, he explained the proper use of pure reason.

The Discipline of Pure Reason

In section I, the discipline of pure reason in the sphere of dogmatism, of chapter I, the discipline of pure reason, of Part II, transcendental discipline of method, of the Critique of Pure Reason, Kant enters into the most extensive discussion of the relationship between mathematical theory and philosophy.[48]

Discipline is the restraint, through caution and self-examination, that prevents philosophical pure reason from applying itself beyond the limits of possible sensual experience. Philosophy cannot possess dogmatic certainty. Philosophy, unlike mathematics, cannot have definitions, axioms or demonstrations. All philosophical concepts must be ultimately based on a posteriori, experienced intuition. This is different from algebra and geometry, which use concepts that are derived from a priori intuitions, such as symbolic equations and spatial figures. Kant's basic intention in this section of the text is to describe why reason should not go beyond its already well-established limits. In section I, the discipline of pure reason in the sphere of dogmatism, Kant clearly explains why philosophy cannot do what mathematics can do in spite of their similarities. Kant also explains that when reason goes beyond its own limits, it becomes dogmatic. For Kant, the limits of reason lie in the field of experience as, after all, all knowledge depends on experience. According to Kant, a dogmatic statement would be a statement that reason accepts as true even though it goes beyond the bounds of experience.[49]

Restraint should be exercised in the polemical use of pure reason. Kant defined this polemical use as the defense against dogmatic negations. For example, if it is dogmatically affirmed that God exists or that the soul is immortal, a dogmatic negation could be made that God doesn't exist or that the soul is not immortal. Such dogmatic assertions can't be proved. The statements are not based on possible experience. In section II, the discipline of pure reason in polemics, Kant argues strongly against the polemical use of pure reason. The dogmatic use of reason would be the acceptance as true of a statement that goes beyond the bounds of reason while the polemic use of reason would be the defense of such statement against any attack that could be raised against it. For Kant, then, there cannot possibly be any polemic use of pure reason. Kant argues against the polemic use of pure reason and considers it improper on the grounds that opponents cannot engage in a rational dispute based on a question that goes beyond the bounds of experience.[49]

Kant claimed that adversaries should be freely allowed to speak reason. In return, they should be opposed through reason. Dialectical strife leads to an increase of reason's knowledge. But there ought to be no dogmatic polemical use of reason. The critique of pure reason is the tribunal for all of reason's disputes. It determines the rights of reason in general. We should be able to openly express our thoughts and doubts. This leads to improved insight. We should eliminate polemic in the form of opposed dogmatic assertions that cannot be related to possible experience.

According to Kant, the censorship of reason is the examination and possible rebuke of reason. Such censorship leads to doubt and skepticism. After dogmatism produces opposing assertions, skepticism usually occurs. The doubts of skepticism awaken reason from its dogmatism and bring about an examination of reason's rights and limits. It is necessary to take the next step after dogmatism and skepticism. This is the step to criticism. By criticism, the limits of our knowledge are proved from principles, not from mere personal experience.

If criticism of reason teaches us that we can't know anything unrelated to experience, can we have hypotheses, guesses, or opinions about such matters? We can only imagine a thing that would be a possible object of experience. The hypotheses of God or a soul cannot be dogmatically affirmed or denied. But we have a practical interest in their existence. It is therefore up to an opponent to prove that they don't exist. Such hypotheses can be used to expose the pretensions of dogmatism. Kant explicitly praises Hume on his critique of religion for being beyond the field of natural science. However, Kant goes so far and not further in praising Hume basically because of Hume's skepticism. If only Hume would be critical rather than skeptical, Kant would be all-praises. In concluding that there is no polemical use of pure reason, Kant also concludes there is no skeptical use of pure reason. In section II, the discipline of pure reason in polemics, in a special section, scepticism not a permanent state for human reason, Kant mentions Hume but denies the possibility that skepticism could possibly be the final end of reson or could possibly serve its best interests.[50]

Proofs of transcendental propositions about pure reason (God, soul, free will, causality, simplicity) must first prove whether the concept is valid. Reason should be moderated and not asked to perform beyond its power. The three rules of the proofs of pure reason are: (1) consider the legitimacy of your principles, (2) each proposition can have only one proof because it is based on one concept and its general object, and (3) only direct proofs can be used, never indirect proofs (e.g., a proposition is true because its opposite is false). By attempting to directly prove transcendental assertions, it will become clear that pure reason can gain no speculative knowledge and must restrict itself to practical, moral principles. The dogmatic use of reason is called into question by the skeptical use of reason but skepticism does not present a permanent state for human reason. Kant proposes instead a critique of pure reason by means of which the limitations of reason are clearly established and the field of knowledge is circusmcribed by experience. According to the rationalists and skeptics, there are analytic judgments a priori and synthetic judgments a posteriori. Analytic judgments a posteriori do not really exist. Added to all these rational judgments is Kant's great discovery of the synthetic judgment a priori.[51]

The Canon of Pure Reason

The canon of pure reason is a discipline for the limitation of pure reason. The analytic part of logic in general is a canon for the understanding and reason in general. However, the Transcendental Analytic is a canon of the pure understanding for only the pure understanding is able to judge synthetically a priori.[52]

The speculative propositions of God, immortal soul, and free will have no cognitive use but are valuable to our moral interest. In pure philosophy, reason is morally (practically) concerned with what ought to be done if the will is free, if there is a God, and if there is a future world. But, in its actual practical employment and use, reason is only concerned with the existence of God and a future life. Basically, the canon of pure reason deals with two questions: Is there a God? Is there a future life? These questions are translated by the canon of pure reason into two criteria: What ought I to do? and What may I hope for? yielding the postulates of God's own existence and a future life, or life in the future.[53]

The greatest advantage of the philosophy of pure reason is negative, the prevention of error. But moral reason can provide positive knowledge. There can't be a canon, or system of a priori principles, for the correct use of speculative reason. However, there can be a canon for the practical (moral) use of reason.
Reason has three main questions and answers:

  1. What can I know? We cannot know, through reason, anything that can't be a possible sense experience; ("that all our knowledge begins with experience there can be no doubt")
  2. What should I do? Do that which will make you deserve happiness;
  3. What may I hope? We can hope to be happy as far as we have made ourselves deserving of it through our conduct.

Reason tells us that there is a God, the supreme good, who arranges a future life in a moral world. If not, moral laws would be idle fantasies. Our happiness in that intelligible world will exactly depend on how we have made ourselves worthy of being happy. The union of speculative and practical reason occurs when we see God's reason and purpose in nature's unity of design or general system of ends. Lo and behold! The speculative extension of reason is severely limited in the transcendental dialectics of the Critique of Pure Reason, which Kant would later fully explore in the Critique of Practical Reason.[54]

In the transcendental use of reason, there can be neither opinion nor knowledge. Reason results in a strong belief in the unity of design and purpose in nature. This unity requires a wise God who provides a future life for the human soul. Such a strong belief rests on moral certainty, not logical certainty. Even if a person has no moral beliefs, the fear of God and a future life acts as a deterrent to evil acts, because no one can prove the non-existence of God and an afterlife. Does all of this philosophy merely lead to two articles of faith, namely, God and the immortal soul? With regard to these essential interests of human nature, the highest philosophy can achieve no more than the guidance, which belongs to the pure understanding. Some would even go so far as to interpret the Transcendental Analytic of the Critique of Pure Reason as a return to the Cartesian epistemological tradition and a search for truth through certainty.[55]

The Architectonic of Pure Reason

All knowledge from pure reason is architectonic in that it is a systematic unity. The entire system of metaphysic consists of: (1.) Ontology—objects in general; (2.) Rational Physiology—given objects; (3.) Rational cosmology—the whole world; (4.) Rational Theology—God. Metaphysic supports religion and curbs the extravagant use of reason beyond possible experience. The components of metaphysic are criticism, metaphysic of nature, and metaphysic of morals. These constitute philosophy in the genuine sense of the word. It uses science to gain wisdom. Metaphysic investigates reason, which is the foundation of science. Its censorship of reason promotes order and harmony in science and maintains metaphysic's main purpose, which is general happiness. In chapter III, the architectonic of pure reason, Kant defines Metaphysics as the critique of pure reason in relation to pure a priori knowledge. Morals, analytics and dialectics for Kant constitute Metaphysics, which is Philosophy and the highest achievement of human reason.[56]

The History of Pure Reason

Metaphysics began with the study of the knowledge of God and the nature of a future world. It was concluded early that good conduct would result in happiness in another world as arranged by God. The object of rational knowledge was investigated by sensualists (Epicurus), and intellectualists (Plato). Sensualists claimed that only the objects of the senses are real. Intellectualists asserted that true objects are known only by the understanding mind. Aristotle and Locke thought that the pure concepts of reason are derived only from experience. Plato and Leibniz contended that they come from reason, not sense experience, which is illusory. Epicurus never speculated beyond the limits of experience. Locke, however, said that the existence of God and the immortality of the soul could be proven. Those who follow the naturalistic method of studying the problems of pure reason use their common, sound, or healthy reason, not scientific speculation. Others, who use the scientific method, are either dogmatists (Wolff) or skeptics (Hume). All of the above methods are faulty. The method of criticism remains as the path toward the completely satisfying answers to the metaphysical questions about God and the future life in another world.

Historically speaking from the point Kant left off, the Critique of Pure Reason led to the great systematic syntheses of German idealism. Hegelians like Bauer, Feuerbach, Marx and even Nietzsche rejected the creative and opted for the destructive potential of the Critique.[clarification needed] Neo-Kantians Cohen and Rickert stressed the philosophical justification of science in the Critique. Heidegger and Heimsoeth stressed the ontology and Strawson the limits of reason within the boundaries of sensory experience. In recent times, Arendt and Lyotard stressed the work of orientation of a limited understanding in the field of world history.[57]

Terms and phrases

Intuition and concept

Kant distinguishes between two different fundamental types of representation: intuitions and concepts.

  1. Concepts are "mediate representations" (see A68/B93). Mediate representations represent things by representing general characteristics of things. For example, consider a particular chair. The concepts "brown," "wooden," "chair," and so forth are, according to Kant, mediate representations of the chair. They can represent the chair by representing general characteristics of the chair: being brown, being wooden, being a chair, and so forth.
  2. Intuitions are "immediate representations" (see B41), that is, representations that represent things directly. One's perception of the chair is, according to Kant, an immediate representation. The perception represents the chair directly, and not by means of any general characteristics.

Kant divides intuitions in the following ways:

  1. Kant distinguishes intuitions into pure intuitions and empirical intuitions. Empirical intuitions are intuitions that contain sensation. Pure intuitions are intuitions that do not contain any sensation (A50/B74). An example of an empirical intuition would be one's perception of a chair or another physical object. All such intuitions are immediate representations that have sensation as part of the content of the representation. The pure intuitions are, according to Kant, those of space and time, which are our mind's subjective condition of coordinating sensibilia. Our representations of space and time are not objective and real, but immediate representations that do not include sensation within those representations. Thus both are pure intuitions.
  2. Kant also divides intuitions into two groups in another way. Some intuitions require the presence of their object, i.e. of the thing represented by the intuition. Other intuitions do not. (The best source for these distinctions is Kant's Lectures on Metaphysics.) We might think of these in non-Kantian terms as first, perceptions, and second, imaginations (see B151). An example of the former: one's perception of a chair. An example of the latter: one's memory of a chair that has subsequently been destroyed. Throughout the Transcendental Aesthetic, Kant seems to restrict his discussion to intuitions of the former type: intuitions that require the presence of their object.

Kant also distinguised between a priori (pure) and a posteriori (empirical) concepts.

English translations

  • Francis Haywood (1838) (First English translation)
  • J.M.D. Meiklejohn (1855)
  • Friedrich Max Müller (1881)
  • Norman Kemp Smith (1929)
  • Wolfgang Schwartz (Concise Text, 1982)
  • Werner S. Pluhar (1996)
  • Paul Guyer and Allen Wood (Cambridge University Press, February, 1999)
  • Marcus Weigelt (Penguin Books, 2007)

See also


  1. ^ Russell, Bertrand (2008). The Problems of Philosophy. Arc Manor LLC. pp. 56–57. ISBN 1604500851. 
  2. ^ Charles George Herbermann, ed (1913). The Catholic Encyclopedia. 8. Encyclopedia Press. p. 604. 
  3. ^ Adler, Mortimer J. (1996). Ten Philosophical Mistakes. Simon & Schuster. p. 94. ISBN 068481868X. 
  4. ^ a b Bertrand Russell. The Problems of Philosophy. p. 57. ISBN 087220099X. 
  5. ^ Joad, C.E.M. (1957). Guide to Philosophy. Dover Publications Inc.. p. 361. ISBN 486202976. 
  6. ^ Charles George Herbermann et al., ed. The Catholic encyclopedia. 10. p. 232. 
  7. ^ Watson, John (1908). The philosophy of Kant explained. J. Maclehose. pp. 62–72. ISBN 0824023358. 
  8. ^ Makkreel, Rudolf A. (1995). Imagination and Interpretation in Kant. University of Chicago Press. p. 21. ISBN 0226502779. 
  9. ^ Chadwick, Ruth F.; Cazeaux, Clive (1992). Immanuel Kant, Critical Assessments: Kant's Critique of Pure Reason. Routledge. p. 43. ISBN 0415074117. 
  10. ^ Mortimer J. Adler. Ten Philosophical Mistakes. pp. 99–100. ISBN 0025003305. 
  11. ^ See Section 25 of the B Edition of The Critique of Pure Reason for Kant's distinction between thinking objects and cognizing objects.
  12. ^ Angeles, Peter A. (1992). Eugene Ehrlich. ed. The Harper Collins Dictionary of Philosophy. Harper Collins. p. 149. ISBN 0064610268. 
  13. ^ Solomon, Robert C. (2001). From Rationalism to Existentialism. Rowman & Littlefield. p. 21. ISBN 0742512412. "In the Transcendental Deduction, Kant distinguishes the transcendental ego from the empirical ego and maintains that only the transcendental ego has these a priori relations with experience." 
  14. ^ Caygill 1995, p. 146
  15. ^ Gardner, Sebastian (1999). Routledge Philosophy Guidebook to Kant and the Critique of Pure Reason. Routledge. pp. 65–66. ISBN 0415119085. 
  16. ^ Henry E. Allison. Kant's Transcendental Idealism. p. 19. ISBN 0300030029. 
  17. ^ Robert Maynard Hutchins, ed (1952). Great Books of the Western World. 42. William Benton/Encyclopedia Britannica Inc.. p. 24. LCCN 55-10348. 
  18. ^ Sebastian Garder. Routledge Guidebook to Kant and the Critique of Pure Reason. pp. 87–88. 
  19. ^ Russell, Bertrand (2009). The ABC of Relativity. Taylor & Francis. pp. 37, 138. ISBN 0415473828. 
  20. ^ Senderowics, Yaron M. (2005). The Coherence of Kant's Transcendental Idealism. Springer. p. 270. ISBN 1402025808. "The problem addressed by Kant presupposes the results of the Transcendental Aesthetics." 
  21. ^ Laird, John (1917). Problems of the Self. Read Books. p. 331. ISBN 1406747027. "... Kant hunts the paralogism which attempts to prove the existence of spiritual substance..." 
  22. ^ Ruth F. Chadwick/Clive Cazeaux. Immanuel Kant, Critical Assessments. p. 104. "... the self is an intrinsically important topic and absolutely central to Kant's philosophy,,," 
  23. ^ Svare, Helge (2006). Body and Practice in Kant. Springer. p. 263. ISBN 1402041181. "Thus, like logic in general, transcendental logic is the result of a process of abstraction in which something originally part of a more comprehensive context is isolated and then examined in this isolated state." 
  24. ^ Sebastian Gardner. Routledge Philosophy Guidebook to Kant and the Critique of Pure Reason. pp. 198–199. ISBN 041511909X. 
  25. ^ a b Immanuel Kant, Critique of Pure Reason, trans. and ed. by Paul Guyer and Allen W. Wood, Cambridge Univ. Press, 1998, pp. 8-9 (translators' introduction).
  26. ^ Roy Wood Sellars (1917). The essentials of philosophy. The Macmillan Co.. p. 83. 
  27. ^ Sebastian Gardner. Routledge Philosophy Guidebook to Kant and the Critique of Pure Reason. p. 75. ISBN 041511909X. 
  28. ^ Howell, Robert (1992). Kant's Transcendental Deduction. Springer. p. 25. ISBN 0792315711. "The basic strand of his argument runs as follows." 
  29. ^ Heidegger, Martin (1997). Phenomenological Interpretation of Kant's Critique of Pure Reason. Indiana University Press. p. 292. ISBN 0253332585. "In the schematism Kant attempts to grasp the synthesis a priori of the productive power of imagination in a unified and original manner." 
  30. ^ Hartnack, Justus (2001). Kant's Theory of Knowledge: An Introduction to the Critique of Pure Reason. Hackett Publishing. p. 87. ISBN 0872205062. 
  31. ^ Sebastian Gardner. Routledge Philosophy Guidebook to Kant and the Critique of Pure Reason. p. 206. ISBN 041511909X. 
  32. ^ Wood, Allen W. (2005). Kant. Wiley-Blackwell. p. 84. ISBN 0631232827. "... Ideas are such that no sensible intuition corresponding to them could ever be given in our experience." 
  33. ^ Allen W. Wood. Kant. p. 84. ISBN 0375757333. "... Our faculty of reason, when it functions properly, makes us subject to certain conceptual illusions or sophistical lines of reasoning..." 
  34. ^ Atkins, Kim (2005). Self and Subjectivity. Wiley-Blackwell. p. 48. ISBN 1405112048. "Our understanding and experiences are limited a priori to the modes of representation enabled by the categories. Importantly the categories only produce knowledge (or experience, that is, empirical concepts) when they are applied to intuitions. It is this principle that runs through all of Kant's arguments in the Paralogisms of Pure Reason." 
  35. ^ Kim Atkins. Self and Subjectivity. p. 49. ISBN 1405112050. 
  36. ^ Kim Atkins. Self and Subjectivity. pp. 49–50. ISBN 1405112050. 
  37. ^ Powell, C. Thomas (1990). Kant's Theory of Self-Consciousness. Oxford University Press. pp. 174, 185, 188. ISBN 0198244486. "The Fourth Paralogism is, in a sense, something of a stepchild, either passed in silence or given minimal treatment in any discussion of the Paralogisms proper." 
  38. ^ Beiser, Frederick C. (2002). German Idealism: the struggle against subjectivism, 1781-1801. Harvard University Press. p. 63. ISBN 0674007697. "For Kant, the great value of skeptical idealism is that it demands some proof or reason for our ordinary beliefs." 
  39. ^ Bennet, Jonathan Francis (1974). Kant's Dialetics. CUP Archive. p. 72. ISBN 0521098496. "Since the fourth paralogism is misplaced, I shall say no more about it." 
  40. ^ Pittman, John (1997). African-American Perspectives and Philosophical Traditions. Routledge. ISBN 0415916394. "The neglect of contemporary ethicists of Kant's first Critique has been particularly unfortunate." 
  41. ^ Sorensen, Roy A. (2003). A Brief History of the Paradox: philosophy and the labyrinths of the mind. Oxford University Press US. p. 287. ISBN 0195159035. 
  42. ^ Roy A. Sorensen. A Brief History of the Paradox. p. 294. ISBN 0195159039. 
  43. ^ Allison, Henry E. (2004). Kant's Transcendental Idealism. Yale University Press. p. 397. ISBN 0300102666. 
  44. ^ Heidegger, Martin (1988). The Basic Problems of Phenomenology. Indiana University Press. p. 30. ISBN 0253204783. "A peculiar feature of this proof is that it tries to infer God's existence from his concept. The philosophical science which in Kant's opinion starts purely from concepts... is ontology... That is why Kant calls this proof... the ontological proof." 
  45. ^ McGrath, Alister E. (2006). The Christian Theology Reader. Wiley-Blackwell. p. 35. ISBN 1405153584. "Now "Being" is clearly not a genuine predicate: that is, it is not a concept of something which could be added to the concept of a thing. It is merely the positing of a thing, or of certain determinations, as existing in themselves." 
  46. ^ Byrne, Peter (2007). Kant on God. Ashgate Publishing Ltd.. pp. 32–36. ISBN 0754640233. 
  47. ^ Caygill 1995, p. 391
  48. ^ Ewald, William Bragg (2008). From Kant to Hilbert: a source book in the foundations of mathematics. Oxford University Press US. p. 136. ISBN 0198505358. 
  49. ^ a b Watkins 2005, p. 375
  50. ^ Watkins 2005, p. 376
  51. ^ Watkins 2005, p. 378
  52. ^ Caygill 1995, p. 98
  53. ^ Caygill 1995, pp. 98–99
  54. ^ Caygill 1995, p. 144
  55. ^ Caygill 1995, p. 110
  56. ^ Caygill 1995, p. 292
  57. ^ Caygill 1995, p. 149


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