User:Kilva/純粹理性批判

純粹理性批判(德語：Kritik der reinen Vernunft)首刷於1781年，再於1787年再版，是德國哲學家伊曼努爾·康德被最多人閱讀過的書籍，並被普遍地認為是哲學史上最具影響力的書籍之中的其中一本。本書常被稱之為康德的「第一批判」，並和「實踐理性批判」與「判斷力批判」合稱「三大批判」。

康德將第一批判看做是對理性主義和經驗主義之間的鴻溝試著架構起一座橋樑的企圖（且特別是為了反擊大衛·休謨的經驗主義），他提出了一個有名的主張：雖然所有的知識都「起源」於經驗，但這並不表示所有都會「形成」經驗。

此一批判是西方哲學主要的著作之一。在《作為意志和表象的世界》中，亞瑟·叔本華寫道：「康德的教誨讓每個了解了的人的心靈裡，都有了根本上的不同。」^[1]

康德對休謨的經驗主義的駁斥[编辑]

康德認為，休謨懷疑論的結論必須基於所有的觀念都是感官經驗的表現（稱之為心智的唯心論）之前提下。但是，如因果之類的基本原則是不能單純由感官經驗得出的。然後，康德的目的即是找出某些方法不靠經驗上的知識來導出因果。康德反對其分析方式，認為分析推理不能告訴我們其他任何一件已自證的事物。相對地，康德主張我們應當使用綜合推理。但這即產生出了一個新的問題：如何擁有不基於經驗觀察的綜合知識，亦即要如何擁有綜合的先驗真理？

伊曼努爾·康德，他正在對俄國官員們講課－由I. Soyockina / V. Gracov所繪，收於加里寧格勒的康德博物館

康德認為存在著綜合的「先驗」真理。他推想那些在幾何與牛頓物理中所找到的敘述即為綜合的「先驗」知識，並且希望能建立起這是如何為真的方法。這也導致他訊問是否有可能在形上學的領域中找尋綜合的「先驗」知識的立基，因為源於柏拉圖的形上學大多數的原則多為和這個世界、上帝或靈魂有關之不可自證但又不能由經驗觀察導出的斷言。這導致了他對形上學最有影響力的貢獻： 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 broach the limits of possible experience but must discuss only those limits, thus furthering the understanding of ourselves qua thinking beings.

This approach provided Kant with the basis to distinguish appearances, that is, objects as they appear to us, from the thing-in-itself, a thought-object considered as independent of sensibility and which, by definition, can never appear to us. In Kant's words, "Concepts without intuitions [are] empty, intuitions without concepts [are] blind". The appearance is only the representation, represented by us externally in space, of the thing-in-itself considered as the matter of intuition prior to its being received by us. "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 under consideration the limitations of our human capacity for knowledge.

Kant termed his critical philosophy "transcendental idealism", which for him is intimately linked with empirical realism. That is, our empirical knowledge is real, but it cannot know what transcends the operations of our cognitive faculties. Transcendental idealism describes Kant's method of seeking the conditions of the possibility of our knowledge of the world and recognizes that there are things that transcend the limits of our cognitive faculties. 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 known world.

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. For Berkeley, something is an object only if it can be perceived. For Kant, on the other hand, perception does not provide the criterion for the existence of objects. Rather, the conditions of sensibility (space and time) and the categories of the understanding provide the "epistemic conditions", to borrow a phrase from Henry Allison, required for us to know objects in the phenomenal world.

Kant's approach[编辑]

「純粹理性批判」企圖回答三個問題：

「我能知道什麼？」
「我應該做什麼？」
「我可能期望什麼？」

康德經由觀察基於理性上的知識（純粹邏輯、先於或無關經驗、或先驗上認知的事物）和基於經驗上的知識（基於感官或後驗上認知的事物）之間的關係來著手處理這些問題。

在康德的觀點中，「先驗」的直覺和概念提供我們一些「先驗」的知識，其中亦提供了我們的「後驗」知識的架構。例如，康德主張空間和時間並不是我們應該視為客觀現實的一部份，而是感知架構（apparatus of perception）的一部份，且因果關係是一種我們強加於自然上頭概念性的構造原則。

換句話說，空間和時間是感知的一種類型，而因果關係則是認知的一種類型。空間和時間與我們的概念性原則和過程先架構了我們的存在。

當我們看到一個盒子是三維的時，這個盒子的形狀可能不是其本質的一部份。康德主張我們對這個盒子的形狀在時空上的感知是來自於和盒子作用的我們，而不只是盒子本身。當我們體驗過事件導致了另一些事件時，這是因為我們在符合我們經驗的自然上有著因果關係的概念。

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 as the forms of our intuition or perception, and the unifying, structuring activity of our concepts. These aspects of mind turn things-in-themselves into the world of experience. We are never passive observers or knowers.

Kant's "I" — the "Transcendental Unity of Apperception" — is similarly unknowable. I am aware that there is an "I," a subject or self that accompanies my experience and consciousness. But since I only experience it in time, which is a "subjective" form of perception, I can know it only indirectly, as object, not as subject.

Transcendental Doctrine of Elements[编辑]

Transcendental Aesthetic[编辑]

Following 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 which 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'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 is an a priori intuition. 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.^[2] 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.

Space and time[编辑]

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.

The first metaphysical expositions unfold by describing what both space and time really are. The argument proceeds according to the following five main points:

Space and time are not in themselves general concepts; rather, they are intuitions. Space is not in itself a concept because one can imagine things external to his or her self, and this feat of the imagination supposes a prior understanding of space. Therefore the internal representation of space can't be drawn from experience by the acquaintance with external sensations and establishing relations between them; rather, experiences with the external are themselves impossible unless they presuppose the ability to understand space. Similarly, the perception of co-existence and succession could not occur without first having an understanding of time.
Space is a necessary representation that is the foundation of all external experiences. We can never imagine anything without space. Time is also a necessary representation, but in a sense that is more powerful, since it underlies every intuition whatsoever.
For space, this a priori necessity is the foundation of all geometrical principles and the possibility of their a priori construction. As for time, it is by the same a priori necessity that we may also find the possibility of philosophical principles concerning time and its axioms.
Neither space nor time are general concepts. In effect, we can't initially imagine anything but one, unitary space and, when we talk about many spaces, we mean that those sub-parts occupy part of the same, unique space. The same reasoning forces the same conclusion for time: different times are just part of the same time. Moreover, the fact that space and time are not concepts can be demonstrated in that space and time are necessary and universal conditions for appearance in general, and so must be intuitions.
Finally, space and time are both infinite (though this is not strictly true, as he explains later in the 'Antinomy of Pure Reason'.) The representation of space is infinite in the sense that "all the parts of space coexist ad infinitum" (A25/B40). Time is similarly unlimited, in that "every determinate magnitude of time is possible only through limitations of one single time that underlies it" (A32/B47-48).

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 concept of a straight line and the number two. He concludes that it is simply impossible (A47-48/B65). Thus, as we can't 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.

But in this case, it wasn't 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 which renders mathematics possible. Time is not a 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 representations. 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 representation. 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.

In the Transcendental Logic, one finds a section (entitled the Refutation of Idealism) from Kant which frees his doctrine from any vestiges of subjective idealism which would either doubt or deny the existence of external objects (B274-79). 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, 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).

Transcendental Logic[编辑]

The Transcendental Logic is that part of the CPR where Kant investigates the understanding and its role in constituting our knowledge. The understanding is defined as the faculty of the mind which 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 which 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.

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.

Transcendental Analytic[编辑]

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. 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 The Refutation of Idealism.

The Metaphysical Deduction[编辑]

In the Metaphysical Deduction 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.^[3]

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.^[3]

Kant begins from Aristotelian logic in defining four aspects in which one can classify any judgment: quantity, quality, relation, or modality.

	1.Quantity of Judgements Universal Particular Singular
2.Quality Affirmative Negative Infinite		3.Relation Categorical Hypothetical Disjunctive
	4.Modality Problematic Assertoric Apodeictic

In each of these ‘moments’ of judgment, there are three alternative classifications; quantity, a judgment may be universal, particular, or singular; relation, a judgment may be categorical, hypothetical, or disjunctive, etc. (A70/B95). These Aristotelian ways of classifying judgments are the basis for his discerning the twelve correlated concepts of the understanding. Kant ultimately distinguishes twelve pure concepts of the understanding divided into four classes of three (A80/B106):

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

The Transcendental Deduction[编辑]

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 by roughly 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.

The Schematism[编辑]

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 categories to sensed phenomenal appearances because the categories are, as Kant says, completely heterogeneous with sense intuition.

The Refutation of Idealism[编辑]

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) entitled "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 permanent 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.

Transcendental Dialectic[编辑]

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.

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 consitutive and regulative uses of reason)

In the introduction, Kant introduces a new faculty, human reason, positing that it is a unifying faculty which 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 which may bring the series of empirical conditions to a close, to obtain knowledge of an 'absolute totality' of conditions, thus becoming unconditioned.

The Paralogisms of Pure Reason[编辑]

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[编辑]

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.

The Soul is simple[编辑]

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.

The Soul is a person[编辑]

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.

the Soul is separated from the experienced world[编辑]

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.

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.

The Antinomy of Pure Reason[编辑]

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.

The Ideal of Pure Reason[编辑]

Pure reason mistakenly goes beyond its relation to possible experience when it concludes that there is a Being who is the most real thing conceivable. 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.

Ontological Proof of God's Existence[编辑]

The Ontological Proof considers the concept of the most real Being and concludes that it is absolutely 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.

Cosmological ("Prime Mover") Proof of God's Existence[编辑]

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.

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

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. That, in turn, is based on its converse, the Ontological 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.

Transcendental Doctrine of Method[编辑]

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[编辑]

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.

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.

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.

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 Canon of Pure Reason[编辑]

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.

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 can not know, through reason, anything that can't be a possible sense experience; (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. We serve God and fulfill our destiny by adapting ourselves to God's Divine will and its purposes.

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 commonest understanding.

The Architectonic of Pure Reason[编辑]

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.

The History of Pure Reason[编辑]

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.

Terms and phrases[编辑]

Intuition and concept[编辑]

Kant distinguishes between two different fundamental types of representation: intuitions and concepts. Intuitions are "immediate representations" (see B41). Concepts are "mediate representations" (see A68/B93).

Mediate representations represent things by representing general characteristics of things. Immediate representations represent things directly. 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. One's perception of the chair, however, is, according to Kant, an immediate representation. The perception represents the chair directly, and not by means of any general characteristics.

Kant divides intuitions into groups in several different ways. First, 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 other physical object. All such intuitions are immediate representations that have sensation as part of the content of the representation. The pure intuitions the human mind possesses are, according to Kant, those of space and time. Our representations of space and time are immediate representations, and do not include sensation within those representations. Thus both are pure intuitions.

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 building 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.

Notes[编辑]

^ http://www.kirjasto.sci.fi/ikant.htm
^ see Henry Allison, "Kant's Transcendental Idealism"
^ ^3.0 ^3.1 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).