Can someone please defend Kant's refutation of idealism in the B-edition, because it seems untenable to me.

First, he claims that 'I' am aware of myself being subjected to a specific temporal order of cognitions. He then claims, for this to happen I need a reference point and since this reference point cannot be 'Time' (since Time is transcendental) it has to be things-in-themselves. And thus, things-in-themselves must exist (idealism is refuted here).

However, things-in-themselves are also transcendental, so this argument is untenable to me. If I cannot even intuit things-in-themselves, how can I use them as a reference point? Secondly, isn't it the function of the pure intuition of time (inner-sense) itself to order the objects in a specific order? I cannot even have appearances without it having a specific order in TIME (time is itself that order). I thought this was clear in the Aesthetic, and since time is pure intuition (a priori), it cannot refute idealism.

A second, and more charitable reading I came across is that the point of reference is actually the objects of outer-sense, i.e, space. But in this case, it doesn't even refute idealism at all (maybe Descartes but not all Berkeley's). Berkeley can definitely agree with this logic because space also is a priori (a mere idea which cannot establish existence of material independent of me).

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    It’s our relationship to noumena that’s transcendental — i.e., we can’t know either way, but we can deduce the general conditions of living and knowing (e.g., we “cannot doubt” there is at least one existing thing..)
    – Joseph Weissman
    Commented Jun 16, 2020 at 19:37
  • Even if I grant you that, how is this sufficient for being a reference point if I cannot intuit it? Commented Jun 16, 2020 at 20:01
  • We have two threads discussing Dicker's reconstruction of Kants RoI, Kant's Refutation of Idealism and How does Kant rule out permanent soul in his argument for the existence of external world? But let me clarify one confusion:"thing outside me" in RoI is not the thing-in-itself. The latter plays no role in RoI, he is refuting empirical idealism about appearances, and the conclusion is the reality of appearances in space and time, in Kant's special sense of "reality".
    – Conifold
    Commented Jun 17, 2020 at 5:50
  • If your interpretation is correct, how is this a refutation of idealism at all? As i mention in the question, this doesn't pose any threat to Berkeley's challenge - to prove existence of anything independent of ideas. Commented Jun 17, 2020 at 12:24
  • That too has been pointed out in the answers I linked, RoI misses its intended target. The interpretation is the standard one.
    – Conifold
    Commented Jun 17, 2020 at 14:02

1 Answer 1


I see you are reading the CPR and asking questions while you read it which is a great exercise in Philosphy. May I suggest Bird's commentary to accompany your reading? (The revolutionary Kant) To try and answer your question: Kant's argument in RoI is not dealing with noumena. The existence of external objects is the existence of a distinction between outer-sense objects. It does refute idealism insofar as it refutes any thesis that sees all that appears as produced by the subject. I am no expert in Berkeley but I will add this: an idealist system in which all that appears is manifestation of the subject is refuted by Kant's RoI. An idealist system in which all that appears is manifestation of another superior subject isn't refuted by Kant's RoI but by the limitation of the field in which knowledge is legitimate. In this case Kant would say that there are no grounds to make such an assertion (see Critique of judgment- theleological judgment-§§73-77)

  • Hi! "an idealist system in which all that appears is manifestation of the subject is refuted by Kant's RoI". How? Is space not a manifestation of the subject (it's pure intuition). Then outer-sense is also contingent on the subject. And so how is Kant proving existence of anything independent of the subject? Commented Jun 17, 2020 at 12:26
  • I wouldn't say that space is a manifestation of the subject. Space is a form of intuition, a determinate form in which objects can manifest. The sensible spatial objects that we encounter are not something created by or inherent to the subject, they are only encountered under a trascendental condition (that of space). THe distinction betwen form an material takes different meanings in different contexts through Kant's works. One of them is here. Space and time are forms, but the material, the sensation, that manifests inside those forms isn't a product of the subject. Thats why Formal idealism
    – Marc
    Commented Jun 17, 2020 at 12:39
  • that which is found in inner sense is "found" in the subject, i.e. can in some sense be regarded as manifestation of the subject. But that which is found in outer sense can in no way be considered as inherent to the subject, though of course the outer sense as a sense-faculty- determinate form of intuition is inherent to the subject.
    – Marc
    Commented Jun 17, 2020 at 12:52

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