Stanford Encyclopedia of Philosophy

 

1. Appearances and Things in Themselves

In the first edition (A) of the Critique of Pure Reason, published in 1781, Kant argues for a surprising set of claims about space, time, and objects:

• Space and time are merely the forms of our sensible intuition of objects. They are not beings that exist independently of our intuition (things in themselves), nor are they properties of, nor relations among, such beings. (A26, A33)
• The objects we intuit in space and time are appearances, not objects that exist independently of our intuition (things in themselves). This is also true of the mental states we intuit in introspection; in “inner sense” (introspective awareness of my inner states) I intuit only how I appear to myself, not how I am “in myself”. (A37–8, A42)
• We can only cognize objects that we can, in principle, intuit. Consequently, we can only cognize objects in space and time, appearances. We cannot cognize things in themselves. (A239)
• Nonetheless, we can think about things in themselves using the categories (A254).
• Things in themselves affect us, activating our sensible faculty (A190, A387).[1]

In the “Fourth Paralogism” Kant defines “transcendental idealism”:

I understand by the transcendental idealism of all appearances [Erscheinungen] the doctrine that they are all together to be regarded as mere representations and not as things in themselves [nicht als Dinge an sich selbst ansehen], and accordingly that space and time are only sensible forms of our intuition, but not determinations given for themselves or conditions of objects as things in themselves [als Dinge an sich selbst]. (A369; the Critique is quoted from the Guyer & Wood translation (1998))

Ever since 1781, the meaning and significance of Kant’s “transcendental idealism” has been a subject of controversy. Kant’s doctrines raise numerous interpretive questions, which cluster around three sets of issues:

(a)

The nature of appearances. Are they (as Kant sometimes suggests) identical to representations, i.e., states of our minds? If so, does Kant follow Berkeley in equating bodies (objects in space) with ideas (representations)? If not, what are they, and what relation do they have to our representations of them?

(b)

The nature of things in themselves. What can we say positively about them? What does it mean that they are not in space and time? How is this claim compatible with the doctrine that we cannot know anything about them? How is the claim that they affect us compatible with that doctrine? Is Kant committed to the existence of things in themselves, or is the concept of a “thing in itself” merely the concept of a way objects might be (for all we know)?

(c)

The relation of things in themselves to appearances. Is the appearance/thing in itself distinction an ontological one between two different kinds of objects? If not, is it a distinction between two aspects of one and the same kind of object? Or perhaps an adverbial distinction between two different ways of considering the same objects?

Sections 2–6 examine various influential interpretations of transcendental idealism, focusing on their consequences for (a)–(c). Section 7 is devoted more narrowly to the nature of things in themselves, topic (b), and the related Kantian notions: noumena, and the transcendental object. The primary focus will be the Critique of Pure Reason itself; while transcendental idealism, arguably, plays an equally crucial role in the other Critiques, discussing them would take us too far afield into Kant’s ethics, aesthetics, and teleology.[2] While transcendental idealism is a view both about space and time, and thus of objects of outer sense as well as inner sense (my own mental states), this entry will focus on Kant’s views about space and outer objects. Kant’s transcendental idealist theory of time is too intimately tied up with his theory of the self, and the argument of the transcendental deduction, to discuss here (see Falkenstein 1991; Van Cleve 1999: 52–61; and Dunlop 2009 for more on Kant’s theory of time).

Before discussing the details of different interpretations, though, it will be helpful if readers have an overview of some relevant texts and some sense of their prima facie meaning. The interpretation of these texts offered in this section is provisional; later, we will see powerful reasons to question whether it is correct. Since some scholars claim there is a change in Kant’s doctrine from the A edition of 1781 to the B edition of 1787, we will begin by restricting attention to the A edition. Section 2.4 discusses what relevance the changes made in the B edition have for the interpretation of transcendental idealism. However, following standard scholarly practice, for passages present in both editions, the A page number followed by the B page number is given (e.g., A575/B603). Works other than the Critique are cited by volume in the “Academy” edition of Kant’s work (Ak.), followed by the page number. At the end of this article can be found a guide to all the editions and translations of Kant used in its preparation.