Title of Work: Kant, Critique of Pure Reason, Transcendental Aesthetic

Date of Meeting: 3/27/09

Preparer of Notes: Paulygon

Summary of Transcendental Aesthethic:

In his introduction, Kant has entitled transcendental “all knowledge which is occupied not so much with objects as with the mode of our knowledge of objects in so far as this mode of knowledge is to be possible a priori”(A12). And a system which is made up of such concepts is entitled transcendental philosophy. However, because such a system is too grand for the present work, he must content himself with what is even more fundamental, namely an analysis of the principles of a priori synthesis. This is the work of the critique of pure reason.
There are two stems of human knowing: sensibility, and understanding. The transcendental aesthetic, then, is concerned with this first stem or component, namely, human sensibility. In human sensibility objects are given to us. And “in so far as sensibility may be found to contain a priori representations constituting the condition under which objects are given to us, it will belong to transcendental philosophy” (B30). As we know from our study of Kant, these a priori representations are precisely the pure sensible intuitions of space and time, which constitute the conditions under which each and every object is give to us.

Detailed Notes:

Transcendental Aesthetic, Section II: Time

Section 4: Metaphysical Exposition of the Concept of Time
(At B38, Kant explains what he means by a “metaphysical exposition”: “By expositio I mean the clear, though not necessarily exhaustive, representation of that which belongs to a concept: the exposition is metaphysical when it contains that which exhibits the concept as given a priori”)

I.  The universality of time

  1. Time cannot be an empirical concept derived from experience
  2. This can be proven because of the way we represent to ourselves simultaneity and succession
  3. We must presuppose time in order to represent things as existing either at one and the same time, or else at different times

II.  The necessity of time

  1. It is impossible to remove time with respect to appearances.
  2. If we remove the appearances or inner states from time, or replace them with others, still we cannot remove time itself. Thus it is necessary and underlies all intuitions.
  3. Hence time is a priori. It alone makes appearances possible.

III.  The various axioms and apodeictic principles of time also rely upon time being an a priori and pure intuition

  1. Take, for example, some principles concerning time:
  2. Time has only one dimension
  3. Different times are not simultaneous but successive
  4. These principles cannot be derived from experience, because if they were, they would not have strict universality, nor apodeictic certainty
  5. Thus the very certainty of these principles relies upon time as an a priori intuition

IV.  Time is not a general concept, but rather time is a pure form of sensible intuition

  1. Unlike concepts, all times are part of one and the same time
  2. Each part of time forms a whole which displays the nature of time just as each part does.

V.  Time must be given as unlimited

  1. Individual times are actually just limitations, determinate magnitudes of one and the same time
  2. This is proof that time is a sensible intution, because when an object is so given all of its parts can only be represented through limitation, then the whole cannot be a concept but rather it must be an immediate a full intuition

Section 5: The Transcendental Exposition of the Concept of Time

I.  The implications for motion

  1. For Aristotle, time is the measure of motion
  2. But for Kant, the concepts of alteration and motion are possible only through and in the representation of time
  3. Alteration depends on time, and motion is simply alteration of place. So time must be considered a priori in order to explain motion
  4. Furthermore, without an a priori sensible intuition of time, Kant argues that it would be impossible for us to have the a priori synthetic knowledge of motion which we do, in fact, have.

Section 6: Conclusions from these Concepts

I.  (a) Time is not something which exists in itself, which inheres in things, or which remains when the subject is removed

  1. If it were self-subsistent, it would be actual and yet not an actual object
  2. If it were an order (or relation) between things themselves, it could not be known a priori
  3. However, on the Copernican revolution, all of this is explainable when we make time the subjective condition under which alone intuition can take place in us

II.  (b) Time is nothing but the form of inner sense

  1. Time is the form of the intuition of our selves and of our inner state
  2. It can’t be the form of outer appearances, because this is the work of space
  3. In order to make up for the non-spatial nature of time, we try to create imagined representations for ourselves, which must of necessity be spatial

III.  (c) Time is the formal a priori condition of all appearances whatsoever

  1. Space is limited only to outer sense
  2. However, time, as the form of inner sense, is the form of all appearances (both inner and outer) whatsoever
  3. All representations (inner and outer) belong as determinations of the mind
  4. Thus all representations belong to our inner state
  5. And our inner state stands under the formal condition of inner intuition
  6. This formal condition of inner intuition is time
  7. Thus time is an a priori condition of all appearance whatsoever
  8. Time therefore has objective validity only in respect of appearances, i.e., with objects of our senses
  9. If we speak of things in general, abstracting from our sensible intuition, then time is nothing
  10. Time is a purely subjective condition of our human intuition and in itself, apart from the subject, is nothing (B52)
  11. The transcendental ideality of time:
  12. Time has an empirical reality, in that it is objective relative to all the objects which are given to our senses
  13. But time has no claim to absolute reality, because properties which belong to things in themselves can never be given to us thorugh the senses
  14. What is meant by transcendental ideality: “if we abstract from the subjective conditions of sensible intuition, time is nothing, and cannot be ascribed to the objects in themselves (apart from their relation to our intuition) in the way either of subsistence or of inherence” (B53)

Section 7: Elucidation

I.  An objection against the transcendental ideality of time:

  1. Alterations are real
  2. This is proved by the fact that change of our own representations is real (even if we were to deny that all outer appearances and their alterations be denied)
  3. Alterations are only possible in time
  4. Therefore time is something real

II.  Kant agrees!

  1. Time is something real: it is the real form of inner intuition
  2. Time is real not as an object, but as the mode of representation of myself as an object; time inheres not in objects, but merely in the subject which intuits them

III.  Time and space therefore are the pure forms of all sensible intuition, and together are what make all a priori synthetic knowledge possible

  1. As such, space and time only apply to objects viewed as appearances, and not as things are in themselves
  2. Kant insists that this leaves the certainty of empirical knowledge unaffected (B56)

IV.  Those who deny the transcendental ideality of space and time are inescapably led to one of two absurdities:

  1. Either mathematical doctrines will lose their apodeictic certainty (because certainty cannot be found in the a posteriori)
  2. Or else a priori mathematical doctrines will not have validity in respect to real things

V.  The transcendental aesthetic cannot be composed of more than the two elements of space and time, since all other concepts belonging to sensibility presuppose something empirical

Section 8: General Observations on Transcendental Aesthetic

I.  Kant wants to clear up misapprehension by explaining as clearly as possible what he understands to be the fundamental constitution of sensible knowledge in general (N.B. this section thus serves as an excellent summary of Kant on sensibility)

  1. All our intuition is nothing but the representation of appearance
  2. The things which we intuit are not in themselves what we intuit them to be
  3. If we remove the subject, then we remove space and time themselves
  4. What the objects are in themselves (considered apart from the receptivity of our sensibility) remains completely unknown to us
  5. We know nothing but our mode of perceiving them
  6. No amount of further clarification of knowledge can ever allow us to know the objects in themselves, apart from appearance

II.  We must distinguish clearly between merely empirical considerations, and the transcendental nature of space and time

  1. In a sense, we can distinguish between different viewpoints, more “objective” views of a particular object
  2. But this all still remains on the level of the appearance of the object, and not the object itself
  3. The empirical object in general does not represent the object in itself
  4. Rather, the relation of the representation to the object cannot be determined on empirical, but only on transcendental, grounds

III.  Kant also wants us to accept the transcendental aesthetic not as a plausible hypothesis, but as a certain and indubitable theorem

  1. In general, his argument here takes the form of a reductio ad absurdam: Think the opposite of the transcendental aesthetic, and then ask the question, “How will this allow us to obtain synthetic a priori propositions?” Then we will be able to conclude that only if space and time are the forms of sensibility can we think in the way that we actually do think.
  2. Suppose time and space are objective, i.e. conditions of the possibility of things in themselves (rather than of our intuition of things)
  3. Then how is it possible to have synthetic a priori truths, such as those of geometry? Only through either concepts or intuitions. And concepts are either a priori or a posteriori:
  4. If a posteriori (empirical), then there is no necessity nor absolute universality, which are characteristic of geometric propositions
  5. If a priori, then we will only be able to attain analytic (and not synthetic) knowledge, i.e. there will be no new knowledge!
  6. Only if the object has an a priori intuition can it serve as a ground for the reality of the synthetic propositions which we do in fact make

IV.  Further confirmation that we cannot know the things in themselves

  1. Since the outer sense only gives us relations between objects (such as extension, motion, moving forces, etc), we cannot know the thing in itself
  2. Furthermore, since the outer objects are the proper objects for my mind, without them I cannot experience myself. There is a connection between self and the outer sense
  3. The same is true of the inner sense: since it only gives relations of succession, coexistence, and endurance, we cannot know the thing itself, in this case, our very self: “Everything that is represented through a sense is so far always appearance, and consequently we must either refuse to admit that there is an inner sense, or we must recognize that the subject, which is the object of the sense, can be represented through it only as appearance, not as that subject would judge of itself if its intuition were self-activity only, that is, were intellectual” (B68).

V.  Objects are not simply illusions, but they are merely appearances. Yet these appearances have objective reality (as empirical).

  1. In fact, it is regarding space and time as real entities which is the illusion.
  2. In the footnote at B70, Kant defines appearance as follows: “That which, while inseparable from the representation of the object, is not to be met with in the object in itself, but always in its relation to the subject, is appearance”

VI.  Some implications for natural theology

  1. God cannot be an object of sensible intuition either to us, or to himself
  2. He does not know in a discursive way (thought), but rather immediately through intuition; yet his intuition does not have the conditions of space and time
  3. God’s knowledge is original, creative, and in no way receptive. He does not know us through spatial, temporal forms.
  4. If God exists, then temporal knowledge is not the ultimate reality

Conclusions of the Transcendental Aesthetic

I.  The pure a priori intuitions of space and time provide one of the two factors necessary for answering the problem of transcendental philosophy: how are synthetic a priori judgments possible?

II.  An a priori judgment involves a concept; but there is a prior and a priori intuition which corresponds to the concept, and which can be connected with it synthetically

III.  However, since such a judgment is based upon intuition, it is valid only for the objects of possible experience.

Questions, Notes:

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