Chapter 69 Chapter 20 Kant

Section 1 German idealism in general Eighteenth-century philosophy was dominated by the English empiricist school, of which Locke, Berkeley, and Hume may be regarded as representatives.There is in these men a contradiction which they themselves seem never to have known, a contradiction between their ethos and their theoretical tendencies.In terms of spiritual temperament, they are citizens with a social heart, they will never go their own way, they are not overly eager for power, and they agree with a tolerant society where everyone can do whatever they want within the scope of the criminal law.They were all amiable, worldly people, gentle and kind.

But while their temperament was social, their theoretical philosophy tended toward subjectivism.Subjectivism is not a new tendency; it existed in late antiquity and was most assertive in St. Augustine; The story has reached a temporary peak.Leibniz believed that nothing in his own experience would change even if the rest of the world perished; nonetheless he was committed to the reunification of the Old and Protestant Churches.Similar paradoxes appear in Locke, Berkeley, and Hume. In Locke, the paradox is still theoretical.As we know from the previous chapter, Locke said on the one hand: "Since the mind has no immediate objects in all its thinking and reasoning but ideas which it can or can meditate on itself, it is clear that our cognition Concerned only with these ideas." He added: "Knowledge is the perception of agreement or disagreement between two ideas." Still, he maintains that we have three kinds of knowledge about the existence of reality: intuitive knowledge about our own existence; Existence, demonstrative knowledge; perceptual knowledge of things presented to the senses.

He maintains that simple ideas are "products of things acting on the mind in the natural way".How he knows this, he does not explain; this claim is indeed beyond "the two concepts agree or disagree". Berkeley took an important step toward ending this paradox.For him there exists only mind and its appearances; the outer world of matter is abolished.But he still failed to understand the full consequences of the epistemological principles he had inherited from Locke.Had he been perfectly consistent, he would have denied the knowledge of God and of all hearts but his own.His feelings as a priest and a man of society prevented him from making such a denial.

Hume was unafraid in his pursuit of theoretical consistency, but he felt no compulsion to make his practice conform to his theory.Hume denies the self and casts doubt on induction and causation.He approves of Berkeley's abolition of matter, but not of Berkeley's proposed substitute in the name of the appearance of God.It is true that, like Locke, he does not recognize any mere idea that does not have antecedent impressions, and no doubt he imagines "impressions" as a state of mind that results directly in the mind because of something outside the mind.However, he cannot admit that this is the definition of "impression", because he has objections to the concept of "because..., as a result...".I doubt very much whether he or his disciples were ever clearly aware of this problem of impressions.Obviously, in his view, since "impression" cannot be defined in terms of causality, it may have to be defined by some internal characteristic that distinguishes it from "idea".He could therefore not claim that impressions produce knowledge of things outside of us, as Locke had, and Berkeley did in a modified form.So he should have thought himself shut in a solipsistic world, ignorant of nothing but his own states of mind and their relations.

Hume, by his consistency, shows that empiricism, when carried to its logical end, produces results that few can admit, and abolishes throughout the sciences the distinction between rational belief and credulity.Locke foresaw this danger.Using the mouth of a hypothetical critic, he issued the following argument: "If knowledge consists in the agreement between ideas, then the fanatic and the rational person are on the same level." In an age weary of "enthusiasm," it is not difficult to convince one that his answer to this criticism is sound.Rousseau came on the stage when everyone turned to reason and gradually became tired of reason, revived "enthusiasm", and admitted the bankruptcy of reason, allowing emotion to decide issues that reason had doubts about.From 1750 to 1794, the utterance of emotion grew louder; at last, so far as France was concerned at least, the Thermidor put a temporary halt to the ferocious proclamation of emotion.Emotion and reason were equally silenced under Napoleon.

In Germany the reaction to Hume's agnosticism took a form much deeper and more subtle than that which Rousseau had originally imposed upon it.Kant, Fichte, and Hegel developed a new philosophy which they wanted to defend knowledge and virtue against the destructive doctrines of the late eighteenth century.In Kant, and still more in Fichte, the subjectivist tendencies begun with Descartes were carried to a new extreme; in this respect there was initially no reaction against Hume.With regard to subjectivism, the backlash begins with Hegel, who, through his logic, strives to establish a new way out of the individual and into the world.

All German idealism is related to the Romantic movement.This relation is evident in Fichte, still more in Schelling; least in Hegel. Kant, the founder of German idealism, was not politically important himself, although he also wrote several interesting treatises on political questions.On the contrary, both Fichte and Hegel advanced political theories that had and still have a profound influence on the course of history.It is impossible to understand both of them without studying Kant first, so I will talk about Kant in this chapter. German spiritualists have certain common features which may be mentioned before proceeding to a detailed discussion.

The critique of knowing as a means to philosophical conclusions was emphasized by Kant and embraced by his successors.Emphasizes the spirit as opposed to matter, and finally draws the claim that only spirit exists.Violently rejected utilitarian ethics in favor of systems supposedly justified by abstract philosophical arguments.There is an air of pedantry not found in the French and English philosophers of the past; Kant, Fichte, and Hegel were university professors lecturing to academic audiences, not gentlemen of leisure lecturing to amateurs.Although their role was partly revolutionary, they themselves were not deliberately subversive; Fichte and Hegel were very clearly committed to the defense of the state.The lives of all these men were exemplary academic ones; their views on moral questions were strictly orthodox.They innovated in theology, but for religion.

With these few quotes, let's go back to study Kant.Section 2 Kant's Philosophy Immanuel Kant (1724-1804) is generally considered to be the greatest of modern philosophers.I personally can't agree with this assessment, but it would be foolish not to acknowledge his importance. Kant lived all his life at or near Königsberg in East Prussia.Although he lived through the Seven Years' War (for a period the Russians occupied East Prussia), the French Revolution, and the early years of Napoleon's career, his external life was academic and perfectly uneventful.He was educated in the philosophy of Leibniz transmitted by the Wulffites, but two influential forces, Rousseau and Hume, made him abandon this philosophy.Hume, by his critique of the notion of causality, awakened him from his dogmatic sleep—or so he said; but the awakening was only temporary, and he soon invented a hypnotic agent which enabled him to fall asleep again.According to Kant, Hume is an opponent who must be refuted, but Rousseau has a deeper influence on him.Kant is a person with very regular living habits. Everyone used to check the watch according to the time when he passed the door of each person on a health walk, but once his timetable was disrupted for a few days; it was when he was reading "Emile" "when.He said that he had to read Rousseau several times, because the beauty of the writing prevented him from paying attention to the content on the first reading.Although Kant's upbringing was that of a pious man, he was a liberal both politically and theologically; he was sympathetic to the French Revolution up to the time of the Terror, and he was a believer in democracy.It can be seen from the following that his philosophy allows appealing to emotion and resists the cold instructions of theoretical reason; a little exaggeration, this may be regarded as a pedantic copy of "Savoy Priest".His principle that everyone should be regarded as an end in himself is a kind of human rights theory; his love of freedom is revealed in the following sentence (about adults as well as children): "No more Nothing is more terrible than the submission of one's actions to the will of another."

Kant's early writings were more about science than philosophy.After the Lisbon earthquake, he wrote a discussion on the theory of earthquakes; he wrote a treatise on winds, and a short essay on whether the westerly winds in Europe were more watery because they crossed the Atlantic Ocean.Physical geography was a subject of great interest to him. The most important of Kant's scientific works is his "General Natural History and Theory of the Heavens" (General Natural History and Theory of the Heavens) (1755), which advocated the nebula hypothesis before the Laplace nebula hypothesis, discusses a possible origin of the solar system.Parts of this work have a marked Miltonian majesty.The book has the credit for being the first to develop a working hypothesis, but it does not present the serious reasons in support of it, as Laplace did.

Some of his hypotheses are purely fanciful, such as the idea that all planets are inhabited and the most distant ones have the best inhabitants; a view that is admirable for the modesty of the earth, but which has no scientific basis. Kant had one of the most skeptical periods of his life when he wrote a marvelous book called Dreams of a Ghost-seer, Illustrated by the Dreams of Met-aphysics) (1766). The "spirit seer" is Pauli of Sweden. His mysticism system was published to the world in a mammoth book. Four copies of this book were sold, three of which were sold to unknown buyers, and one sold to Kant.Kant called Swedenborg's system "fantastic"; he suggested, half-seriously, half-jokingly, that Swedenborg's system was perhaps no more whimsical than orthodox metaphysics.Still, he doesn't entirely despise Sweden's Boli.His mystical side is present, though not so much in the writings; it praises Swede Pauli, who he says is "very sublime." He, like all others of his time, wrote a treatise on the sublime and the beautiful.The night is sublime, the day is beautiful; the sea is sublime, the land is beautiful; man is sublime, woman beautiful; and so on. The Encyclopedia Britannica says: "Because he was never married, he kept into old age the habits of his eager and studious youth." I really wonder if the author of this entry is a bachelor or a married man people. Kant's most important book is (The Critique of Pure Reason) (first edition, 1781; second edition, 1787).The object of this work is to show that, although there is nothing in our knowledge which goes beyond experience, there are nevertheless parts which are a priori and are not inductively inferred from experience.The a priori part of our knowledge contains, according to him, not only logic, but many things that cannot be classified into logic or deduced from logic.He draws apart two distinctions that Leibniz confuses.On the one hand, there is a distinction between "analytical" and "synthetic" propositions; on the other, there is a distinction between "a priori" and "empirical" propositions.There is something to be said about these two distinctions. An "analytical" proposition is one in which the predicate is part of the subject; for example "a tall man is a man" or "an equilateral triangle is a triangle".This kind of proposition is the conclusion of the law of contradiction; if it is claimed that tall people are not human beings, it will be self-contradictory. A "synthetic" proposition is one that is not an analytic proposition.All propositions which we know through experience are synthetic propositions.For example, we cannot discover truths like "Tuesday is rainy" or "Napoleon was a great general" by analyzing concepts alone. But Kant, unlike Leibniz and all other philosophers before him, did not admit the opposite, that all synthetic propositions are known through experience.This brings us to the second of the two distinctions above. An "empirical" proposition is one which we cannot know except by means of sense perceptions, either our own or of someone else whose proof we admit.Facts of history and geography belong to this class; so do scientific laws whenever our knowledge of the truth of scientific laws depends on observational data.Conversely, an "a priori" proposition is a proposition that can be extracted from experience, but once it is known, it is seen to have a basis other than experience.When a child learns arithmetic, he experiences two pebbles and two other pebbles, and observes that he is experiencing a total of four pebbles, which can help him to learn in this way.But when he understands the general proposition, "Two plus two is four," he no longer needs verification by examples; this proposition has a certainty which induction can never ascribe to general laws.All propositions in pure mathematics are a priori propositions in this sense. Hume had shown that causality is not analytic, and he reasoned that we cannot be sure of its truth.Kant admits that the law of causality is synthetic, but still maintains that the law of causality is known a priori.He argued that arithmetic and geometry are synthetic, yet equally a priori.Kant then formulates his problem in these terms: How is it possible to have a priori synthetic judgments? The answer to this question and its various conclusions form the theme. Kant's solution to this problem was one he was very confident in.It took him twelve years to find this solution, but, now that his theory had taken shape, it took him only a few months to write his entire tome.In the preface to the first edition, he said: "I dare to assert that there is not a single metaphysical problem that has not been solved, or at least has not yet been proposed for its solution." In the preface to the second edition, he compares himself to Copernicus, saying that he A Copernican revolution has been accomplished in philosophy. According to Kant, the external world creates only the stuff of sensation, but our own mental apparatus organizes this stuff in space and time, and supplies us with the concepts by which we understand experience.The thing-in-itself, the cause of our sensations, is not cognizable; the thing-in-itself is not in space or time, it is not a substance, nor can it be described by any of those other general concepts that Kant called "categories."Space and time are subjective and part of our organ of perception.But because of this, we can be sure that everything we experience exhibits the properties taught by the sciences of geometry and time.If you always wear blue glasses, you can be sure to see everything blue (this is not Kant's example).Also, since you mentally always wear a pair of space glasses, you must always see everything in space.Geometry is therefore a priori in the sense that it must apply to everything experienced; but we have no reason to suppose that anything analogous to geometry applies to things in themselves which we do not experience. Kant said that space and time are not concepts, but two forms of "intuition". (The original German word for "intuition" is "Anschauung", which literally means "watching" or "observation". Although the word "intuition" in English has become a definite translation, it is not completely a perfect translation. .) However, there are also a priori concepts, that is, the twelve "categories" derived by Kant from the various forms of the syllogism.The twelve categories are divided into four groups in three groups: (1) Quantitative: unity, plurality, and totality; (2) Quantitative: reality, negativity, and limitation; (3) Of relation: entity and accident, cause and effect, interaction; (4) of mode: possibility, existence, necessity.Space and time are subjective in the sense that these categories are subjective in the same sense—in other words, our mental makeup is such that these categories apply to everything we experience , but there is no reason to suppose that they apply to things in themselves.There is, however, a paradox about "cause"; for Kant sees things in themselves as the cause of sensations, whereas free will he sees as the cause of events in space and time.This paradox is not an accidental oversight, it is an essential part of his system. A large part of the book is devoted to explaining the fallacies that arise from the application of space and time, or categories, to the unexperienced. In doing so, Kant argues, we find ourselves trapped in an "antinomy"— That is, trapped in two contradictory propositions, each of which is clearly provable.Kant cites four such antinomies, each consisting of a thesis and an antithesis. In the first antinomy, the thesis is: "The world has a beginning in time, and is limited in space." The antithesis is: "The world has no beginning in time, and no limit in space; in terms of time and Space is infinite on both sides.” The second antinomy proves that every composite substance is both made and not made of simple parts. The thesis of the third antinomy asserts that there are two kinds of causality, one is causality according to the law of nature, and the other is causality according to the law of freedom; the antithesis asserts that there is only causality according to the law of nature. The fourth antinomy proves that there is and is not an absolutely necessary being. This part of the Critique had a great influence on Hegel, so that Hegel's dialectics proceeded entirely through antinomies. In a famous section, Kant sets out to destroy all purely intellectual proofs of the existence of God.He shows some other reasons for his belief in the gods; these reasons he will later describe in The Critique of Practical Reason.But for the time being his purpose is purely negative. He said that there are only three proofs of the existence of God relying on pure reason; the three proofs are ontological proofs, cosmological proofs, and physical theological proofs. According to his account, the ontological proof defines God as ensrealissimum (the most real being); that is, the subject of all predicates absolutely belonging to Being. Those who believe in the soundness of this proof maintain that since "being" is such a predicate, this subject must have "being" as a predicate, in other words, must exist.Kant proposes that being is not a predicate as an objection.He said that the hundred tala of my pure imagination and the hundred real tala could have all the same predicates. The cosmological proof says: If there is something, then an absolutely necessary being must exist; since I know that I exist; therefore an absolutely necessary being exists, and that must be the ensrealissimum (the most real being).Kant maintains that the last step in this proof is a duplicate of the ontological proof, so this proof is also refuted by what has been said above. The physical-theological proof is the well-known ideology argument, but with a metaphysical cloak.This justifies the claim that the universe exhibits an order, which is evidence that there is a purpose.Kant discusses this proof with respect, but points out that at best it proves that there is a "Designer" and not a "Creator" and thus fails to give a proper conception of God.He asserted that "the only possible rational theology is that which is based on, or seeks to be guided by, the moral law." God, liberty, and immortality are three "rational ideas," he said.But pure reason, though it enables us to form these ideas, cannot itself prove their reality.The significance of these ideas is practical, that is, related to morality.The purely intellectual use of reason produces fallacies; the only legitimate use of reason is for moral purposes. The exercise of reason in practice is briefly discussed near the end, and it is developed in more detail in "Critique of Practical Reason" (1786).The argument is that the moral law requires justice, that is, happiness in proportion to virtue.Only God's will can guarantee this, but it is obviously not guaranteed in this world.So there are gods and an afterlife; and there must be liberty, for otherwise there would be no such thing as virtue. Kant in his Metaphysic of Morals The ethical system revealed in (1785) has considerable historical significance.The book speaks of "categorical imperatives," a term that, at least as a phrase, is well known outside professional philosopher circles.As might be expected, Kant has nothing to do with utilitarianism, or with any doctrine which attaches to morality a purpose other than morality itself.He needed, he said, "a completely isolated metaphysics of morality without an iota of theology, physics, or metaphysics." He went on to say that all moral concepts reside entirely a priori in reason and emanate from it.Moral worth exists only when a person acts out of a sense of duty; it is not enough to act as the duty could have dictated.A businessman who is honest out of selfishness, or a person who helps others out of a benevolent impulse, is not considered virtuous.The essence of morality should be derived from the concept of law; because although everything in nature acts according to law, only rational creatures have the ability to act according to the idea of ​​law, that is, to act by will.The idea of ​​an objective principle, in so far as it compels the will, is called the imperative of reason, and the formula of the imperative is called the imperative. There are two imperatives: saying "if you want to achieve such and such a purpose, you must do this and that" is a false imperative; saying that a certain action has nothing to do with any purpose is always objective and necessary, It is a definite statement.The categorical imperative is synthetic and a priori.Kant deduced its nature from the concept of law: "As soon as I think of a categorical imperative, I know at once what it contains. For apart from the law, the imperative contains only the necessity of the maxim being consistent with the law, but the law contains no restriction on itself. condition, so what remains is only the general universality of the law, the code of conduct should conform to this universality, and only this conformity can make the imperative appear necessary. Therefore, there is only one categorical imperative, which is actually: ·According to that kind of one standard rule to act, relying on this standard rule, you can at the same time be able to ·It becomes·be·universal·regular·law." Or say: "Ru·this·go·action·action: ·like·ran·your·action·be·standard·will· Through your will to become universally natural law-like." As an example of the role of the categorical imperative, Kant pointed out that it is wrong to borrow money, because if everyone tried to borrow money, there would be no money left to borrow.In the same way it can be stated that theft and murder are condemned by the categorical imperative.But there are also some actions that Kant must have considered wrong, but which cannot be justified by his principles, such as suicide; a melancholic may well want everyone to commit suicide.In fact, Kant's maxim seems to refer to a necessary criterion of virtue rather than a sufficient one.If we want to get a sufficient standard, we may have to give up Kant's purely formal view and take some consideration of the effects of actions.Kant, however, affirms that virtue is not determined by the expected result of an action, but by the principle of which the action itself is its result; and if this is admitted, no more specific maxim than his up. Kant maintains that we should act by treating each individual as an end in itself, although Kant's principles do not seem to entail this conclusion. This can be regarded as an abstract form of human rights theory, so the same criticism is inevitable. If this principle is taken seriously, it is impossible to reach a decision as soon as two people's interests conflict.This difficulty is particularly evident in political philosophy, which requires a principle, such as majority preference, according to which the interests of some can be sacrificed, if necessary, for the interests of others.If there is to be any political ethic, the purpose of politics must be one, and the only purpose consistent with justice is the happiness of society.However, it is also possible to interpret Kant's principle not to mean that each is an absolute end, but that in determining an action that affects many, all should count equally.So interpreted, this principle can be seen as providing an ethical basis for democracy.According to this interpretation, it will not be subject to the above-mentioned criticism. Kant's vigor and freshness of mind in old age are expressed in his Perpetual Peace (1795).In this work he advocated a federation of nations formed by a covenant forbidding war.He said that reason completely condemns war, and that only international governments can prevent war.The internal political system of each member state of the federation should be a "republican" political system, but he defined the word "republic" to mean the separation of executive and legislative.He does not say that there should be no kings; in fact, he says that the best government is easiest to obtain under a monarchy.The book was written under the influence of the Terror, so he was skeptical of democracy; he said that democracy must be despotism because it established the executive power. "The so-called 'all people' who carry out their own policies are not all of them, but only a majority of them; so at this point the general will contradicts itself and contradicts the principle of freedom." The wording of this sentence reveals Rousseau's influence, but the important idea of ​​a world federation as a means of securing peace did not come from Rousseau. Since 1933 Kant has been out of favor in his country because of this work.Section 3 Kant's Theory of Space and Time The most important part is the doctrine of space and time.In this section I intend to give this doctrine a critical examination. It is not easy to explain Kant's theory of space and time clearly, because the theory itself is not clear.and the Prolegomena It is covered in both; the latter explanation is easier to understand, but not as complete as that in the Critique.I want to introduce the theory first, as plausible as possible; after the explanation I try to criticize. Kant believes that the direct object of perception is half due to external things, and half due to our own perception organs.Locke had first accustomed the common man to this idea: Secondary qualities—colour, sound, smell, and so on—are subjective and do not belong to the object itself.Kant, like Berkeley and Hume, went a step further and said that the main quality is also subjective, although he does not do it in the same way as them.Kant most of the time does not doubt that our sensations have a cause, which he calls the "thing in itself" or "noumena" (noumenon).What appears to us in perception he calls "appearance" is composed of two parts: the part due to the object, which he calls "sensation"; the part due to our subjective apparatus, which he says makes the manifold Arranged in a certain relationship.He called this latter part the form of the phenomenon.This part is not itself a sensation, and therefore independent of the accidents of the environment; it is something we carry with us, so it is consistent, and a priori in the sense that it does not depend on experience.The pure form of sensibility is called "pure intuition" (Anschauung); there are two forms of this, namely space and time, the one of external perception and the other of internal perception. To prove that space and time are a priori forms, Kant holds two kinds of arguments, one is metaphysical arguments, and the other is epistemological arguments, which he calls transcendental arguments.Arguments of the former kind follow directly from the nature of space and time, arguments of the latter kind follow indirectly from the fact that there can be pure mathematics.The argument about space is given in more detail than the argument about time, because he thinks that the latter is fundamentally the same as the former. There are a total of four metaphysical arguments about space. (1) Space is not an experiential concept derived from external experience, because space is presupposed when sensation is attributed to certain external things, and external experience is only possible through the representation of space. (2) Space is an a priori necessary representation, which is the basis of all external perception; for although we can imagine the absence of things in space, we cannot imagine the absence of space. (3) Space is not a deduced concept or a general concept about the general relationship of things, because there is only one space, and the "spaces" we call are its parts, not some instances of it. (4) Space is represented as an infinite and already determinate quantity, which contains in itself all its parts; this relation is not the same as that of a concept to its instances, so that space is not a concept but an Anschauung ( intuitive). Transcendental arguments about space come from geometry.Kant believed that although Euclidean geometry is synthetic, that is to say, it cannot be deduced only by logic, but it is recognized a priori.He thought that proofs in geometry depended on figures; for example, we can see that, given two intersecting straight lines at right angles to each other, only one straight line can be drawn through their point of intersection at right angles to both.In his view, this knowledge does not come from experience.But the only way my intuition can foresee what it will find in an object is if it contains only the form of my sensibility, before all the real impressions in my subject.Objects of sensation must obey geometry, because geometry is about the way we perceive, so we cannot perceive it in other ways.This explains why geometry, though synthetic, is a priori and necessary. The argument about time is essentially the same, except that counting requires time, and geometry is replaced by arithmetic. Let us now examine these arguments one by one. The first of the metaphysical arguments about space says: "Space is not an empirical concept drawn from external experience. For, in order to attribute certain sensations to something outside me [that is, to and My spatial location is something in a different spatial location], and in order for me to perceive these sensations as separate from each other, juxtaposed so that they are not only different but at different locations, for this reason the representation of space must has already been grounded [zumGrunde liegen]." External experience is thus only possible through spatial representations. "Being outside of me [that is, in a different place from where I am]" is a difficult sentence.As a thing-in-itself, I am nowhere, and nothing is spatially outside of me; all that can be said is my body as a phenomenon.Therefore, the real meaning is exactly what is said in the second half of the sentence, that is, I perceive different objects in different places.The mental image that arises in one's mind is equivalent to that of a cloakroom attendant who hangs different coats on different pegs; the individual pegs must have existed, but the waiter's subjectivity arranges the coats. Here lies a difficulty which Kant seems never to have been aware of, and which is present throughout his theory of the subjectivity of space and time.What impels me to arrange the objects of perception as they are and not otherwise?For example, why do I always see people's eyes above the mouth, not below?According to Kant, eyes and mouth exist as things in themselves, causing my separate perception representations; But the eyes and mouth have nowhere equivalent to the spatial arrangement that exists in my perception.Contrast this with the physical theory of color.We don't think there are colors in matter in the sense that our perceptual representations have colors, but we do think that different colors correspond to different wavelengths.But because fluctuations involve space and time, according to Kant, among the various causes of our perception representations, there is no such thing as fluctuations.另一方面，如果像物理学所假定的那样，我们的知觉表象的空间和时间在物质界中有对应物，那么几何学便可以应用到这些对应物上，而康德的论点便破产了。康德主张精神整列感觉的原材料，可是他从不认为有必要说明，为什么照现在这样整列而不照别的方式整列。 关于时间，由于夹缠上因果关系，这种困难更大。我在知觉雷声之前先知觉闪电；物自体甲引起了我的闪电知觉，另一个物自体乙引起了我的雷声知觉，但是甲并不比乙早，因为时间是仅存在于知觉表象的关系当中的。那么，为什么两个无时间性的东西甲和乙在不同的时间产生结果呢？如果康德是正确的，这必是完全任意的事，在甲和乙之间必定没有与甲引起的知觉表象早于乙引起的知觉表象这件事实相当的关系。 第二个形而上学论点主张，能想像空间里什么也没有，但是不能想像没有空间。我觉得任何郑重议论都不能拿我们能想像什么、不能想像什么作根据；不过我要断然否认我们能想像其中一无所有的空间。你可以想像在一个阴暗多云的夜晚眺望天空，但这时你本身就在空间里，你想像自己看不见的云。魏亨格曾指出，康德的空间和牛顿的空间一样，是绝对空间，不仅仅是由诸关系构成的一个体系。可是我不明白，绝对空虚的空间如何能够想像。 第三个形而上学论点说：“空间不是关于一般事物关系的推论的概念或所谓的一般概念，而是一个纯粹直观。因为第一，我们只能想像〔sichvorstellen〕单独一个空间，如果我们说到“诸空间”，意思也无非指同一个唯一的空间的各部分。 这些部分不能先于全体而作成全体的部分……只能想成在全体之中。它〔空间〕本质上是唯一无二的，其中的杂多者完全在于限度。”由此得出论断：空间是一个先天的直观。 这个论点的主眼在否定空间本身中的复多性。我们所说的“诸空间”既不是一般概念“一个空间”的各实例，也不是某集合体的各部分。我不十分知道，据康德看这些空间的逻辑地位是什么，但是无论如何，它们在逻辑上总是后于空间的。现代人几乎全采取空间的关系观，对采取这种观点的人来说，无论“空间”或“诸空间”都不能作为实体词存在下去，所以这个论点成了无法叙述的东西。 第四个形而上学论点主要想证明空间是一个直观，不是概念。它的前提是“空间被想像为〔或者说被表象为，vorgestellt〕无限而·已·定定量。”这是住在像柯尼斯堡那样的平原地方的人的见解；我不明白一个阿尔卑斯山峡谷的居民如何能采取这种观点。很难了解，什么无限的东西怎样会是“已定的”。我本来倒认为很明显，空间的已定的部分就是由知觉对象占据的部分，关于其它部分，我们只有一种可能发生运动之感。而且，假如可以插入一个真不登大雅的论点，我们说现代的天文学家们主张空间实际上不是无限的，而是像地球表面一样，周而复始。 先验的论点（或称认识论的论点）在《绪论》里讲得最好，它比形而上学论点明确，也更明确地可以驳倒。我们现下所知道的所谓“几何学”，是一个概括两种不同学问的名称。 一方面，有纯粹几何，它由公理演绎结论，而不问这些公理是否“真实”；这种几何不包含任何由逻辑推不出来的东西，不是“综合的”，用不着几何学教科书中所使用的那种图形。 另一方面，又有作为物理学一个分支的几何学，例如广义相对论里出现的几何学；这是一种经验科学，其中的公理是由测量值推断出来的，结果和欧几里德的公理不同。因此，这两类几何学中，一类是先天的，然而非综合的；另一类是综合的，却不是先天的。这就解决了先验的论点。 现在试把康德提出的有关空间的问题作一个比较一般的考察。如果我们采取物理学中认为理所当然的观点，即我们的知觉表象具有（从某个意义上讲是）物质性的外在原因，就得出以下结论：知觉表象的一切现实的性质与知觉表象的未感知到的原因的现实性质不同，但是在知觉表象系统与平原因的系统之间，有某种构造上的类似。例如，在（人所感知到的）颜色和（物理学家所推断的）波长之间有一种相互关系。同样，在作为知觉表象的构成要素的空间和作为知觉表象的未感知原因系统的构成要素的空间之间，也必定有一种相互关系。这一切都依据一条准则：“同因，同果”及其换质命题：“异果，异因”。因此，例如若视觉表象甲出现在视觉表象乙的左边，我们就要想甲的原因和乙的原因之间有某种相应的关系。 照这个看法，我们有两个空间，一个是主观的，一个是客观的，一个是在经验中知道的，另一个仅仅是推断的。但是在这方面，空间和其它知觉样相如颜色、声音等并没有区别。在主观形式上，同样都是由经验知道的；在客观形式上，同样都是借有关因果关系的一个准则推断出来的。没有任何理由把我们关于空间的知识看得跟我们关于颜色、声音和气味的知识有什么地方不一样。 谈到时间，问题就不同了；因为如果我们坚守知觉表象具有未感知的原因这个信念，客观时间就必须和主观时间同一。假若不然，我们会陷入前面结合闪电和雷声已讨论过的那种难局。或者，试看以下这种事例：你听某人讲话，你回答他，他听见你的话。他讲话和他听你回答，这两件事就你来说都在未感知的世界中；在那个世界里，前一件事先于后一件事。而且，在客观的物理学世界里，他讲话先于你听讲话；在主观的知觉表象世界里，你听讲话先于你回答；在客观的物理学世界里，你回答又先于他听讲话。很明显，“先于”这个关系在所有这些命题中必定是同样的。所以，虽然讲知觉的空间是主观的，这话有某种重要的意义，但是讲知觉的时间是主观的，却没有任何意义。 就象康德所假定的那样，以上的论点假定知觉表象是由“物自体”引起的，或者也可以说是由物理学世界中的事件引起的。不过，这个假定从逻辑上讲决不是必要的。如果把它抛弃掉，知觉表象从什么重要意义上讲也不再是“主观的”，因为它没有可对比的东西了。 “物自体”是康德哲学中的累赘成分，他的直接后继者们把它抛弃了，从而陷入一种非常像唯我论的思想。康德的种种矛盾是那样的矛盾：使得受他影响的哲学家们必然要在经验主义方向或在绝对主义方向迅速地发展下去；事实上，直到黑格尔去世后为止，德国哲学走的是后一个方向。 康德的直接后继者费希特（1762—1814）抛弃了“物自体”，把主观主义发展到一个简直像沾上某种精神失常的地步。他认为“自我”是唯一的终极实在，自我所以存在，是因为自我设定自己；具有次级实在性的“非我”，也无非因为自我设定它才存在。费希特作为一个纯粹哲学家来说并不重要，他的重要地位在于他通过《告德意志国民》（Addressesto theGermanNation）（1807—08）而成了德国国家主义的理论奠基者；《告德意志国民》是在耶拿战役之后打算唤品德国人抵抗拿破仑。作为一个形而上学概念的自我，和经验里的费希特轻易地混同起来了；既然自我是德意志人，可见德意志人比其他一切国民优越。费希特说：“有品性和是德意志人，无疑指的是一回事。”在这个基础上，他作出了整个一套国家主义极权主义的哲学，在德国起了很大的影响。 他的直接后继者谢林（1775—1854）比较温厚近人，但是主观程度也不稍差。他和德国浪漫主义者有密切关系；在哲学上，他并不重要，固然他在当时也赫赫有名。康德哲学的重要发展是黑格尔的哲学。