¹ Langton, Rae, Kantian Humility: Our Ignorance of Things in Themselves (Oxford: Clarendon Press, 1998Google Scholar; paperback edn., 2001).

² Allison, Henry, Kant's Transcendental Idealism (New Haven, CT: Yale University Press, 1983).Google Scholar

³ Kantian Humility, pp. 66–7. To back this claim up, Langton cites a sentence from Kant's unpublished notes.

⁴ Ibid., pp. 2–3, 211. The closest she comes to repairing this neglect is over the closing 8 pages of her book, where she raises the question of how Kant's views on the subjectivity of space and time could be reconciled with the realism she wants to attribute to him. But her goal here is not to attempt a reconciliation but a divorce — to insist that what Kant has to say about the subjectivity of space, time, and the spatio-temporal properties of things carries no implications for the nature of our knowledge of causes, forces and powers.

⁵ However, when the unknowability problem is probed further, and questions are raised about why Kant supposed that we cannot know the absolutely inner or intrinsic properties of things, Langton's approach ends up being much less elegant. In fact, it flounders. More will be said about this later in this article.

⁶ The alternative that our cognitive constitutions stand in reciprocal causal relations to objects outside of us leads to a kind of absolute idealism according to which the subject constitutes not merely the internal world of its own experiences, but the external world as well.

⁷ ‘… the Kantian philosopher completely abandons the spirit of his system when he says that objects make impressions on the senses, arouse sensations, and so produce impressions. For according to the Kantian doctrine the empirical object, which is only just an appearance, can neither be found outside of us nor be anything other than a representation, whereas, again according to this doctrine, we do not know the least thing about the transcendental object…’ Jacobi, Friedrich Heinrich, David Hume über den Glauben oder Idealismus und Realismus (Breslau: G. Loewe, 1787Google Scholar; repr. in facsimile: New York: Garland, 1983), p. 220.

⁸ The same point can be made about the passages Langton (pp. 135, 136) cites in her defence from the Postulates (B293–4) and the Third Analogy (A212–13/B256–60). All that Kant says in the first passage is that we cannot conceive a community of substances without representing them as related in space, since it is only in space that we can schematize force effects and causal interactions (as accelerated or retarded motion, rarefaction or condensation, or change of motion due to collision). He does not say that a community of substances, considered as things in themselves, would be impossible under any other circumstances. Likewise, all that Kant says in the second passage is that the coexistence of substances could not be perceived by us apart from reciprocal causal relations, and that such relations are necessary for the experience of the community of substances. He does not deny that it would at least be coherently thinkable that some of these relations could have some ground in the intrinsic properties of things in themselves.

Langton's appeals at pp. 133–4 and p. 138 to Kant's remarks on Leibniz at A274/B330 and Fortschritte, Ak. 20:283–4, fail for the same reason. In these passages Kant does not say that Leibniz could not provide for causal relations or a reciprocal community between substances that possess only intrinsic properties. He only says that such relations and such community would have to take the form of a pre-established harmony rather than of physical influx — and he adds that physical influx is only conceivable when constructed in space and time.

Langton's appeal at p. 137 to Anfangsgründe, Ak. 4:497–8, is even more strained. All that Kant says in this passage is that a body's resistance to penetration cannot be accounted for by appeal to the principle of non-contradiction. Saying that solidity must instead be accounted for by appeal to a force of repulsion does not by itself imply that this force could not be an intrinsic property of body, much less that it could not be grounded on an intrinsic property.

⁹ Langton takes this more obviously controversial first premiss to be a direct consequence of the claim that we can only have sensory experience through being affected. She claims that, if we must be affected to have experience, then what our experience must be of is the very powers or forces that affect us — which are all relational (p. 139). As alluded to earlier, this invests B67 with a direct or naive realist thesis that the text does not obviously endorse. B67 only talks about the nature of what we come to know through being affected, not about the nature of the affecting object.

¹⁰ Langton's, appeal at pp. 134–5Google Scholar to A272/B319 is particularly question-begging. On her own interpretation, all that this passage proves is that Kant rejects the supervenience of spatial properties on intrinsic properties. But why does he reject it? By itself, the text gives us no clue, and when taken in context — and the context is the Amphiboly, where Kant is concerned to charge that Leibniz went wrong through failing to take the subjective — and in particular the sensible — conditions under which we arrive at concepts into account (A260/B316, A270/B326), it rather indicates that Kant's reasons have nothing to do with those given in the Nova Dilucidatio argument. Spatio-temporal relations are not reducible to intrinsic properties of things in themselves because they are instead grounded in the receptive constitution of the cognizing subject. It is the transcendental ideality of space and time that establishes the conclusion for Kant, though Langton, p. 211, wants at all costs to avoid having to make this admission. The same point can be made about Langton's carefully selective citation of A44/B61–2, which she reports as criticizing Leibniz for claiming that our senses give us a merely confused knowledge of things in themselves. Why does Kant think Leibniz was wrong about this? The actual reason Kant goes on to give is not that our senses tell us only about relations, and relations are not reducible to intrinsic properties of things, as Langton would have it, but rather that our senses tell us about spatio-temporal relations, which are grounded in our subjective constitution rather than in features of things in themselves, so that were all reference to the cognizing subject removed, these relations themselves would disappear. This point is repeated in the Amphiboly at A270/B326.