Transcendental aesthetics

The transcendental aesthetic is the first part of the transcendental elementary doctrine in Immanuel Kant's work The Critique of Pure Reason .

Kant understood the term aesthetics in its original Greek meaning as sensual perception (from Greek aesthesis). The transcendental aesthetic is thus a theory of perception, or with Kant's concept of sensuality as the basis of knowledge. It is followed by the transcendental logic - the theory of thinking . Thus, according to Kant, in purely temporal terms, sensual perceptions come first and then thinking. But knowledge is equally dependent on intuition and thinking.

In the transcendental aesthetic, Kant primarily dealt with the importance of space and time for human perception. Since he saw the spatial as the basis for geometry and the temporal as the basis for arithmetic, transcendental aesthetics is at the same time a theory about how pure mathematics is possible.

Transcendental Elementary Doctrine (General Epistemology)                             Transcendental aesthetics (theory of perception)     Transcendental Logic (Theory of Thought)                               Transcendental Analytics (theory of concepts and principles, judgment)     Transcendental dialectic (logic of appearances, conclusions)

The transcendental aesthetic within the architecture of the Critique of Pure Reason

Pure intuition

The first section of the transcendental aesthetic (B 33-36) is a tightly packed sequence of definitions on which Kant then based the KrV.

An intuition arises only when an object (things-in-themselves) affects the mind in some way . By mind, Kant means the entire (conscious and unconscious) scope of the human mind. Affecting is a process that is still preconscious so that it cannot be described as such and one cannot speak of causality either. Man has a faculty that Kant calls receptivity , in order to get ideas out of affection . This process is called sensuality and is the only source of intuitions. In contrast, concepts arise from the mind. All linguistic content of consciousness does not come from sensuality. But there is no thinking that is not somehow related to the notions. Both together (sensuality, concepts) are the "two stems of human knowledge" (B 29). Why this is so, Kant left open. He dispensed with a final justification (e.g. a creation), but pointed out that both stems of knowledge "perhaps arise from a common but unknown root." (B 29)

When an object affects the faculty of imagination, it produces sensations . Sensations are still pre-linguistic. Views are empirical if they relate to the object that manifests itself in the sensation. An appearance consists of matter , which corresponds to the sensation, and of form , which ensures that the manifold contained in an appearance has an order, has a structure. While matter, i.e. sensation, can only be given a posteriori due to the process of affection, the pure form is already present a priori in the mind. So the process of ordering takes place in the mind.

Pure ideas contain no sensations, so nothing empirical. Pure form of sensual intuition is a priori contained in the mind. There are therefore elements of sensual intuition, namely those which bring order into the perceived multiplicity which the mind contributes so that an intuition emerges from a sensation. Kant also called these pure forms pure intuition . When one thinks of a body, impenetrability, hardness or color are sensations. The concepts of substance, force or divisibility, which are also connected with the concept of a body, cannot be perceived. They are structuring terms that come from the mind. If one tries now to think the concept of the body without sensations and without concepts of the understanding, there is always something left, namely extension and shape. This is part of the pure a priori intuition.

The transcendental aesthetic a priori has the function of isolating sensuality and also of thinking of appearance without the concepts of the understanding, “so that nothing remains but pure intuition and the mere form of appearance.” (B 36)

"In this investigation it will be found that there are two pure forms of sensual perception as principles of a priori knowledge, namely space and time, [...]" (B 36)

Metaphysical discussion of space (§ 2) and time (§ 4)

Kant treated space and time one after the other, but used congruent parallel arguments. By metaphysical discussion he understood an argument that shows that the object examined is a priori.

Kant differentiated as properties of the mind an external sense , in which objects (appearances) are presented in space, and an internal sense , which looks at the mind itself or its internal state. In the internal sense, everything has at least a relation to time. To prove the a priori of space and time, Kant used four arguments (B 38/39 and B 46-48):

Reasons for the a priori of space and time in Kant

room	time
1. In order to be able to see sensations as something outside, there has to be a space.	1. You cannot imagine a sequence if there is not the time.
2. One cannot imagine that there is no space.	2. One cannot imagine that there is no time.
3. The space itself is something undivided. Individual rooms are always parts of the room itself.	3. Time itself is something undivided. Individual periods of time are always part of a time itself.
4. Space is imagined as an infinite given size.	4. The original idea of ​​time is unrestricted.

In order to better understand Kant's arguments, it is helpful to use the terms spatiality and temporality when speaking of space and time as such. The first two arguments show against empiricism that space and time are a priori. The other two arguments show against rationalism that it is a question of forms of intuition and not mere concepts.

Space is not a property of things, rather “space” encompasses all objects that appear to us externally, side by side. “Space has empirical reality and transcendental ideality.” That is, it has objective validity for everything that can appear to us as external sense, but it is nothing as soon as the conditions of the possibility of all experience are removed. Time is as general and necessary as space and has just as empirical reality as transcendental ideality, but in contrast to space it is the more fundamental principle, because regardless of whether external perceptions or (non-spatial) internal states, “all appearances are in of time and necessarily stand in the relationships of time. "

Transcendental discussion of space (§ 3) and time (§ 5)

In the transcendental discussion of space and time, Kant wanted to show that these pure perceptions are conditions for the possibility of knowledge. Space and time are synthetic a priori if additional knowledge can be derived from them without recourse to empirical views.

In accordance with the stipulations from the introduction to the KrV, Kant examined geometry as a branch of mathematics, the knowledge of which is derived from the given space. A concept that shows how synthetic statements can be derived a priori from time as a form is the theory of motion in mechanics. Kant argued for this with three points (B 42-43):

1. Space and time themselves are not concepts, but forms of perception. They are not contingent properties "that stick to objects".
2. Space and time cannot be empirical views, because otherwise geometry and pure physics would not be able to make a priori statement.
3. Space and time are dependent on the knowing subject. They are a form of human knowledge. They only apply “for us” and not “in themselves”.

From this Kant concluded that space and time as necessary elements of experience, of appearing reality, have empirical reality. In relation to their being-in-themselves, as a property of things in themselves, they are a mere possibility of thinking. Kant called this "transcendental ideality".

“So we assert the empirical reality of space (with regard to all possible external experience), although the transcendental ideality, that is, that it is nothing, as soon as we omit the condition of the possibility of all experience, and that space is something that is related to things in themselves itself lies at the bottom of it. "(B 44)

The thesis of transcendental ideality is unusual in the sense that it includes the assertion that space and time do not exist independently of perceiving beings. This runs radically against normal intuition , since it is assumed in everyday life that the universe also existed in space and time when there was no human being. However, Kant offered an argument for his unusual thesis: He declared that not only space and time are given a priori, but that there is also synthetic knowledge a priori, such as geometry . Kant concluded that the a priori character was incomprehensible if space and time were transcendentally real, i.e. a recognizable part of things in themselves . One can assume that space and time are real, but man cannot recognize this beyond the empirical framework of the phenomena. This led him to the hypothetical view of the transcendental ideality:

“If space (and thus also time) were not a mere form of your perception, which contains conditions a priori, under which only things can be external objects for you, which are nothing in themselves without this subjective condition: you could a priori to make out nothing synthetically about external objects. It is therefore undoubtedly certain, and not merely possible, or also probable, that space and time, as the necessary conditions of all (external and internal) experience, are merely subjective conditions of all our views [...]. "(B 66)

Possibility of pure mathematics

According to Kant, pure mathematics is possible because space and time lie within us as a priori forms.

The geometry treated spatial relationships. For example, that the straight line is the shortest connection between two points is a synthetic proposition a priori. Because the decomposition of the concept of the straight line only results in this quality and nothing of size. We need the intuition, but not the experience, because the idea of ​​space is already within us. The universality and necessity of geometry are based on it.

The arithmetic calculates. According to Kant, it is basically counting in time. Since time is also a pure form of sensuality in us, the general and necessary validity of arithmetic propositions lies in the inner view of time.

By defining space and time as empirically real and transcendentally ideal, Kant established the apodictic certainty of mathematics.

criticism

Kant's argument for the transcendental ideality of space and time has been criticized in two ways:

On the one hand, it was doubted that the geometry is actually a synthetic a priori knowledge. Some mathematicians and philosophers declare that geometry is analytical, others claim that it is a posteriori.

On the other hand, Kant's conclusion is criticized for the best explanation : It does not seem clear at all that the a priori character of space and time or geometric knowledge can only be understood if space and time are not properties of things in themselves. It could also be that these findings are a priori - for example became innate knowledge in the course of evolution - and that there is still a non-subjective space (or a time).

For example, Albert Einstein and Hans Reichenbach thought it wrong to see space and time as properties of our perception. According to the theory of relativity , they saw space and time as properties of external things. This argument is based on the concepts of space and time in physics, the findings of which Kant understood as empirical, while in transcendental aesthetics he referred to space and time of the visual, human imagination as part of the mind. The fact that the latter is three-dimensional Euclidean with an independent, linear time, can hardly be doubted, even according to modern knowledge. If one regards (three-dimensional) Euclidean geometry like Kant as a consequence of this faculty of imagination, one must understand its theorems, as Kant explicitly stated, as synthetic knowledge a priori. That on the basis of this, one can analytically / algebraically construct a non-Euclidean geometry in the sense of Gauss and Riemann (and even more abstract in the sense of Grothendiek et al.), Which in general eludes the visual imagination and is based on the physical model conception of space-time, which were primarily developed by Einstein, is just as little in contradiction to Kant's theses as the fact that arbitrary analytical / algebraic generalizations of geometry are developed a priori with the help of other intellectual functions from concepts, which they too (as, according to Kant, all mathematics) become knowledge a priori that do not necessarily have anything to do with the physical reality of space (and time).

Remarks

1. ↑ The third argument for time is repeated in the transcendental discussion. There was an editorial error between the first and the second edition of the KrV.
2. ↑ In § 10 of the Prolegomena, Kant also used arithmetic as an example of synthetic knowledge a priori based on time.
3. ↑ The reverse conclusion that there is no space and no time in things as such is not permissible, since, according to Kant, no statements can be made about things in themselves.
4. ↑ In the transcendental discussion of time, Kant pointed out that his statements on space are also valid for time.

literature

• Immanuel Kant : Critique of Pure Reason. (KrV) (1st edition 1781 = A, 2nd edition 1787 = B). In:
  • Kant's works. Academy text output. Volume IV. Verlag Walter de Gruyter, Berlin 1968, pp. 1–252. Or
  • Kant. Works in ten volumes. Published by Wilhelm Weischedel. Wissenschaftliche Buchgesellschaft, Darmstadt 1975, volume 3 = first part, volume 4 = second part.
• Rudolf Eisler: Kant Lexicon. Reference work on all of Kant's writings, letters and handwritten legacy. Olms, (5th reprint of the Berlin 1930 edition) 1989, ISBN 3-487-00744-4 .
• Walter Gölz: Kant's "Critique of Pure Reason" in plain language. Text-related presentation of the train of thought with explanation and discussion. Mohr Siebeck, Tübingen 2006, ISBN 3-8252-2759-6 (UTB).
• Felix Grayeff : Interpretation and presentation of the theoretical philosophy of Kant. A commentary on the basic parts of the Critique of Pure Reason. With an index by Eberhard Heller. 2nd edition, Meiner, Hamburg 1977 (original edition 1951), ISBN 3-7873-0180-1 .
• Otfried Höffe : Kant's Critique of Pure Reason. The foundation of modern philosophy. 2nd edition Beck, Munich 2004, ISBN 3-406-50919-3 .
• Georg Mohr, Markus Willaschek (ed.): Critique of pure reason. Classic laying out. Akademie Verlag, Berlin 1998, ISBN 3-05-003277-4 .
• Heinrich Ratke: Systematic hand dictionary to Kant's critique of pure reason . Meiner, Hamburg 1991, ISBN 3-7873-1048-7 .
• Werner Bernhard Sendker: The very different theories of space and time. The transcendental idealism of Kant in relation to Einstein's theory of relativity. Der Andere Verlag, Osnabrück 2000, ISBN 3-934366-33-3 , der-andere-verlag.de (PDF; 0.7 MB).
• Peter F. Strawson : The Bounds of Sense. An Essay on Kant's Critique of Pure Reason. London 1966 (German: The Limits of Sense. A Commentary on Kant's Critique of Pure Reason. Athenaeum, Frankfurt 1992, ISBN 3-445-07018-0 ).
• Holm Tetens : Kant's “Critique of Pure Reason”. A systematic commentary. Reclam, Stuttgart 2006, ISBN 978-3-15-018434-9

Web links

• All works and letters in full text - University of Bonn
• Entry. In: Rudolf Eisler: Kant-Lexikon (1930)
• Vorländer: history d. Philosophy. §33. The transcendental aesthetic
• Werner Bernhard Sendker: The very different theories of space and time. The transcendental idealism of Kant in relation to Einstein's theory of relativity . (PDF; 703 kB)