[9] Cf. Kant's proof of the first analogy.
Here there is no way of avoiding the conclusion that Kant is deceived by the ambiguity of the phrase 'a thing external to me' into thinking that he has given a proof of the existence of bodies in space which is compatible with the view that they are only phenomena, although in reality the proof presupposes that they are things in themselves. In the 'proof', the phrase 'a thing external to me' must have a double meaning. It must mean a thing external to my body, i. e. any body which is not my body; in other words, it must be a loose expression for a body in space. For, though the 'proof' makes us appeal to the spatial character of things external to me, the _Refutation_ as a whole, and especially Remark II, shows that it is of bodies in space that he is thinking throughout. The phrase must also, and primarily, mean a thing external to, in the sense of independent of, my mind, i. e. a thing in itself. For the nerve of the argument consists in the contention that the permanent the perception of which is required for the consciousness of my successive states must be a _thing_ external to me in opposition to the representation of a thing external to me, and a thing external to me in opposition to a thing external to me can only be a thing in itself. On the other hand, in Kant's conclusion, 'a thing external to me' can only mean a body in space, this being supposed to be a phenomenon; for his aim is to establish the reality of bodies in space compatibly with his general view that they are only phenomena. The proof therefore requires that things external to me, in order that they may render possible the consciousness of my successive states, should have the very character which is withheld from them in the conclusion, viz. that of existing independently of me; in other words, if Kant establishes the existence of bodies in space at all, he does so only at the cost of allowing that they are things in themselves.[10]
[10] The ambiguity of the phrase 'external to me' is pointed out in the suppressed account of the fourth paralogism, where it is expressly declared that objects in space are only representations. (A. 372-3, Mah. 247). Possibly the introduction of an argument which turns on the view that they are not representations may have had something to do with the suppression.