Kant’s Transcendental Aesthetic, Part II: Time

How does Kant Justify A Priori Synthetic Claims about the Nature of Objects?

Contents:

1. Time and Motion
2. Things in Themselves
3. Time as the Form of Inner Sense
   • “Inner Sense”
   • Time as the Form of Inner Sense
4. Notes
5. References

Time and Motion

After discussing space as a precondition for a priori synthetic judgments about the spatial properties of objects, Kant moves on to consider time by way of contemplating motion as a property of objects. As an elementary consideration, he relates the phenomenon of motion to Aristotle’s conception of alteration of place (in Sect. 5). For Aristotle, any alteration of place for any substance can be understood in terms of its capacity to take on contrary properties of place, but not at the same time. This is as much to say that motion yields contrary properties of place that are only intelligible as a function of time.

Kant ties this point about the relationship between space and time to the possibility of the a priori synthetic as follows:

Only in time can two contradictorily opposed predicates meet in one and the same object, namely, one after the other. Thus, our concept of time explains the possibility of that body of a priori synthetic knowledge which is exhibited in the general doctrine of motion, and which is by no means unfruitful.”

[B48-B49]

Time is what fundamentally grounds the possibility of a priori synthetic knowledge of moving objects and of alteration in general. How does it do so? Because alteration, which requires that one and the same thing be capable of taking on contrary properties, would be unintelligible without the concept change through of time. Change of place, motion, involves an alteration of a thing’s properties that would conflict with the principle of non-contradiction (it cannot be the case that a is both p and not p) unless the alteration of its properties was qualified as occurring at different times.

It might be reasoned that a conflict with the principle of non-contradiction would render any motion or alteration unintelligible without the concept of time. Without the concept of time, the world would not merely be unintelligible; it would be fundamentally, structurally so. Our minds would be fundamentally incapable of applying any logic to the problem of change. But that is evidently not the case. It certainly is possible to understand the phenomenon of change even if it is only in a purely formal sense.

An understanding of time as an a priori feature of our cognitive abilities can be brought out by a comparison with the priority of space. We arrive at our concept of space in the Transcendental Aesthetic by abstracting away all the features of our experience except those that are necessary for any experience of space, namely extension and figure. It is because of its priority to any potential representation (it is the foundational background, it might be said) that it becomes a necessary feature of any representation. By reasoning back to what is ontologically primary, to what must be if anything else based upon it is to exist, Kant is able to bring out what is indispensably necessary for our experience of the world as we find it.

Now, we observe that every alteration and all motion involve occur in time. Time, along with space, is therefore an a priori condition for those phenomena, phenomena that are basic to our experience. The experience of drawing a line may serve as an illustration: as the line is drawn, an interval in space is created that represents succession, a notion foundational to our concept of time. By the same token, the line simultaneously exists on a piece of paper–another fundamental feature of our concept of time. We can furthermore reason with a priori necessity that the greater the interval, the longer the extent of succession or that a shorter interval would yield a lesser extent of succession. But such principles “cannot be derived from experience, for experience would give neither strict universality for apodeictic certainty” (B47). Therefore, the capacity for evidently true propositions must lie within us.

It does so as an outcome of the categorical features of our intellect in relation to the basic structural features of our experience. All such features are “transcendental” in that they allow for the possibility of a priori judgments. Such arguments ultimately serve Kant’s aim of challenging Hume’s skepticism regarding causality. Consider that the structure of a causal relationship is tied directly to the concept of alteration.

Things in Themselves

Kant emphasizes that our empirical experience of objects is conditioned by the forms of space and time, but also writes that we must distinguish our sensory intuitions from things in themselves. What are the latter? Our first clue might be taken from Kant’s use of the word “ideality” to describe the pure ideas of space and time. Kant tells us that we can recognize the “ideality,” as opposed to the empirical reality, of space and time by considering them in abstraction from all other general properties of sensation.
once we have done so, we can consider them as pure, ideal abstractions.

But the way our notion of their ideality arises, as something present once the other conditions of sensation have been abstracted away, highlights something further: they are forms of sensibility oriented toward the sensible. This happens to be a characteristic feature of transcendental concepts in general, but what is important for our present purpose is that it may, as such, be contrasted with the “objects” as they are in themselves prior to the application to them of the fundamental forms of our perception. Space and time, being properties of our way of experiencing objects, Kant argues, cannot be held to be properties of things in themselves. This sets a limit to what we can know about objects in themselves (nothing), while, at the same time, grounding our inner experience of objects in forms of sensory intuition that can be used as the basis for a priori synthetic claims about their nature, such as it is, for us.

One way to look at what Kant has accomplishes by this move is to see that he is trading away the notion that we have any epistemic access to things in themselves, their true reality, for solid grounding in the world as we experience it through the forms of intuition that condition our experience. It is within these forms of intuition that we gain the possibility of an “objective” reality that can be made known to us insofar as we can make a priori synthetic claims about it. This might be taken to be Kant’s answer to what became known as “the problem of the external world” and how we may know it. His answer is of course, “nothing,” so far as things in themselves are considered; nevertheless, we gain a foundation in reality as we experience it, insofar as our understanding is related back to our mode of experiencing it.

Time as the Form of Inner Sense

Kant’s description of time as “the form of inner sense”¹ perplexes many readers. What does he mean by these terms and in what sense is time the “form” of inner sense?

Inner Sense

Let’s begin with the expression “inner sense.” It is, obviously contrasted with the expression “outer sense.” What is characteristic of the range of inner sense is that it includes phenomena that exist in the mind and not outside it. For example, imagined scenarios and memories exist only in the mind and not outside it.² These are rather straightforward examples. Things get slightly more complicated when we turn to contemplate our “consciousness of our own existence.” Our conscious awareness is something “in” us, in the sense that we do not find it available to us as an object of our awareness anywhere “outside” us in the world of our experience. We do not experience our consciousness as an object of our experience in the sense that we experience trees, rocks, and barking dogs as objects. Rather, the way we do experience it is as a thing that takes the objects of our experience for its own objects. That is to say, it is only when our consciousness takes on an object of our experience that we are able to become aware of it as a thing that thinks of any object.

This complicates the notion of an inner sense, because it suggests that our inner sense is also a sense of something outer. This is correct. Kant writes,

The consciousness of my existence in me is bound up in the way of identity with the consciousness of a relation to something outside me, and it is therefore experience not invention, sense not imagination, which inseparably connects this outside something with my inner sense. For outer sense is already in itself a relation of intuition to something actual outside me, and the reality of outer sense, in its distinction from imagination, rests simply on that which is here found to take place, namely, its being inseparably bound up with inner experience, as the condition of its possibility.”

Note “a” to Bxl

Our inner awareness of our consciousness concerns various mental activities that involve an awareness of some outer object. What must be remembered in this case is simply that what is being contemplated, our own consciousness, is itself something internal rather than external.

Time as the Form of Inner Sense

Now let’s consider what is meant by saying that time is the form of inner sense. Let’s begin by returning to the idea that our awareness of our own consciousness requires that it take up an object. The object of perception becomes the content of our awareness when we think of an object. This may remind us of the introductory section to the Transcendental Aesthetic where Kant tells us that any “appearance” requires both content and form to be understood.³ This is the right path to follow. Just as is the case with our outer perceptions, which can be analyzed in terms of matter and form, so, it appears, our inner intuition requires both content and form if an understanding of our own consciousness is to take shape. We have considered the content of our consciousness, but what may be said about its form?

Here we may consider again three propositions expressed earlier:

1. Kant’s statement, “Time is nothing but the form of inner sense, that is, of the intuition of ourselves and of our inner state.”
2. We have no immediate intuition of our own consciousness as an object.
3. Time is the form whereby we are able to contemplate our own consciousness awareness.

Time is the form of our inner awareness. It is prior to our conscious awareness in the sense that it only if we are able to conceive ourselves as thinking the contents of our thoughts in time successively and as coexisting simultaneously with the flow of our thought does it becomes possible to relate moments of awareness in time to one underlying consciousness. All this gains added clarity once it is considered that the Kant’s remarks may be contextualized as having been aimed against Hume’s skepticism concerning the very notion of a unified self. Hume writes

“we may observe that what we call a mind, is nothing but a heap or collection of different perceptions, united together by certain relations, and suppos’d, tho’ falsely, to be endow’d with a perfect simplicity or identity.”⁴

This is Hume’s concept of the mind as a theater for our perceptions. For Kant, the form that unites the passing objects of our awareness is time. It is by taking them under the form of time that they may be united together and related to one thing.

Notes

1. B49 ↩︎
2. See the text of note a in Bxl. ↩︎
3. B34 ↩︎
4. Hume’s Treatise of Human Nature , 1.4.2 ↩︎

References

1. Immanuel Kant, Immanuel Kant’s Critique of Pure Reason (1929), trans. Norman Kemp Smith, Bedford/St. Martin’s Press, Boston, 1965. Available online here.
2. David Hume, Treatise of Human Nature (1739), Oxford University Press, 1975.