I'm certain this question must have been asked many times before, but I could not find an answer searching the archived posts here. So please excuse me as I am new to this forum and might have posted a duplicate.

My question is this: "If I take away the thinking subject, the whole material world must vanish, as this world is nothing but the phenomenal appearance in the sensibility of our own subject" (CPR, A 384).

So how does Kant reconcile this with the fact that the universe existed long before any perceiving subjects were around?

I am aware of one possible answer, namely that time itself is just a form of intuition, but this does not make it any clearer to me. Is he saying objects (such as suns and planets) existed, but not as phainomena, but noumena instead? Does not make it any clearer either.

I would appreciate any pointers, to either a post or article which could help me clear this up.

  • 5
    "Before" and "after" are only ways of organizing our experience, which includes the universe existing before us. It existed "before" us because our appearances line up that way, we happen to sequence them in time. But it makes little sense to ask what an atemporal entity independent of us, the thing in itself, was doing "before" us. To ask the question we fall into the "transcendental illusion", pretending to "look" at something beyond our experience as if through God's eye. But our eye isn't God's, and our categories of experience (like time and matter) do not apply beyond the experience.
    – Conifold
    Commented Jan 10, 2020 at 3:26
  • 1
    What makes you say the universe existed before any perceiving subjects? Is this not an assumption? There is a popular view that the first division of the whole or first broken-symmetry was that of subject/object. .
    – user20253
    Commented Jan 10, 2020 at 13:15
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    "What makes me say the universe existed before any perceiving subjects"? Well, Kant's own theory about the formation of stars in the early universe, for one.
    – henoida
    Commented Jan 10, 2020 at 15:48
  • "Perhaps our Earth existed for a thousand or more years before it was constituted so as to support people, animals, and plants." (Universal natural history and theory of the heavens, I:353)
    – henoida
    Commented Jan 10, 2020 at 16:47
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    Other than ignoring your own birth, as a naturally occurring physical process, or do you hold that birth is simply a perception? Or do you hold to the idea that you, as a single human (experience) are the one and only. That would make you your own God. Think about it. CMS
    – user37981
    Commented Feb 9, 2020 at 17:13

5 Answers 5


My question is this: "If I take away the thinking subject, the whole material world must vanish, as this world is nothing but the phenomenal appearance in the sensibility of our own subject" (CPR, A 384).

So how does Kant reconcile this with the fact that the universe existed long before any perceiving subjects were around?

There is no contradiction unless one equates "vanished" with "non-existent". Vanish, I believe, means to disappear, not to become "non-existent". When we say the criminal "vanished", we do not mean that the criminal no longer existed, but that he was no longer perceived. When there is no perceiver, there is nothing perceived. There are no phenomena. But that has no bearing upon whether noumena continue to exist.


When reading Kant's CPR It is always important to remember that he is responding to Humean skepticism. He accepts Hume's argument against absolute knowledge. He is attempting to formulate a ground for any kind of objective knowledge whatsoever.

He assumes that mathematics can be the source of such a ground. Hence, he begins with expositions for time and space. Moreover, given that skepticism essentially attacks the premises of logical arguments, he attempts divorce mathematics from logic. But, he introduces the symbiotic condition that what is sensible must be made intelligible what is intelligible must be made sensible.

His attempt, however, is well-grounded. Kant criticizes the principle of the identity of indiscernibles long before modern mathematical logicians had rejected it when formulating first-order logic. Kant relegates the principle to logic while attributing numerical difference to spatial intuition. If you look up numerical identity in Strawson's book "Individuals," you can get a sense of how skepticism is the underlying factor driving all of this. Philosophers use the term "reidentification" to speak of how we accept a perception of an object moving in and out of our field of vision as being singular.

When considering Kant's references to space and time, it is useful to keep in mind the trichotomy consisting of syntax, semantics, and pragmatics. Syntax studies the signs of a language, semantics studies the possible meanings those signs may have, and pragmatics studies the relationship of a language to language users. The sad state of affairs that exists in the foundations of mathematics stems from the intractable positions of analytical philosophers and logicians against properly addressing pragmatics. Kant's assumption that mathematics can ground objective knowledge is a matter of pragmatics rather than the metaphysics at the heart of objections. And this is what must be understood when using Kant's explanation of time and sense as conditions of sensibility.

If Kant had not introduced a distinction between phenomena and noumena, there would be no object corresponding with the phenomena of sensible intuition. Then, critical philosophy would degenerate into solipsism. He is not denying an external reality. He is simply conforming with the constraint skepticism places on our ability to assert knowledge of that reality.

One problem with your question is that you are overlooking Kant's statement that matter is "that in appearance which corresponds to sensation." So, whatever is to be called "material" is to be correlated with appearances through sensation. And a page or so after your quoted passage he reiterates that "matter" only refers to the sensations attached to outer substances and not those substances themselves.

When I think about Kant, I find it useful to consider "indispensibility arguments" for the existence of abstract objects. My original scientific interest had been biology. If the theory of evolution is essentially correct, how does mankind have any facility through which to know the material truth of reality? I certainly have no evidence that mathematics is anything but a product of human experience. And, formalism in the strict sense of analytical philosophy maintains that necessity, even that of mathematics, follows from stipulated rules. Consequently, there is the joke about mathematicians be platonists except on Sunday.

Were to give credence to assertions commonly made in scientific publications, I would seem to live in a world where mathematics proves the existence of dimensions I cannot witness in any way. Indispensibility arguments ask people to believe in things they cannot witness for the sake of believing in a reductionist philosophy. The next time you hear that human thought can be reduced to Turing machine intelligence, insist upon the explicit details. It is a belief about science without merit.

And, laughably, the academic community who rejected Kant used arguments denying the existence of mathematical objects. Now, for the sake of reductionism (and atheism in many cases), their inheritors use arguments asking people to believe in such.

Before his logicism, Bertrand Russell proposed that projective geometry might be a candidate for Kant's "pure geometry." Projective geometry is ubiquitous in the mathematics of physics. The truth tables of classical propositional logic satisfy the axioms of a finite affine plane with an associated with a projective plane proven unique up to isomorphism. Modern notions of foundations would reject this basis because of circularities.

But, if knowledge of external objects is restricted by skepticism to the relational form of sensory perceptions, it would seem that making sense of a circular ground is required. Leibniz happened to believe this to be possible. Hilbert's popular view of mathematical existence is incompatible with this.

  • No offense intended, but that is a lot of text for the essential (perfectly correct and appropriate) answer "You did not understand what 'material' means here". So much so that it gets hard to see how all that answers the question, since most of the text seems to be irrelevant to it.
    – Philip Klöcking
    Commented Mar 7, 2021 at 21:53

Conifold's comment is elegant and helpful. You also asked for pointers to posts or relevant articles. I don't have one specific thing but reading around the subject can be really worthwhile and help attain a deeper understanding. If you're under time pressure this may not be so helpful but you can always pick and choose.

I would suggest - even if it sounds far too out of left field - reading books V-VIII of Plato's "Republic" (they aren't very long). I sometimes joke that philosophy was invented in those chapters (I certainly wasn't the first to say so!). Jokes aside, in addition to their profound general influence, there are some quite startling similarities with Kant's metaphysics. Even if you've read them before, you're never wasting time doing so again.

Foucault wrote about Kant although I'm not sure if he went beyond analysing the texts on ethics. Still Foucault has so many articles spread across various collections, it's worth having a quick look.

Bear with me here, I haven't wholly lost the plot but in 1865, a Scottish philosopher named James Hutchinson Stirling published the first English language commentary on Hegel called "The Secret of Hegel". A core part of the book involved tracing Kant's work through to Hegel's. It's been a while since I've read it but it's likely to contain material pertinent to your question.

Lastly, it may be worth seeking clarification in the work of Kant's 'disciples', Fichte and Schelling.


Note that Kant clearly says that e.g. the moon exists when we are not directly looking at it (this is part of the very point of the Third Analogy of Experience). This "taking away" that he mentions in the passage you cite is very abstract: imagine a physical object with no possible concrete relationship with us, not even an intelligible relation with our very notions of physical possibility and actuality. One that we could never experience in a substantial way at all, more occulted than Russell's teapot. We have "taken ourselves away" from such objects, so what is there to say about them? {Not much; though in some cases, we are allowed a few sentences.} On the other hand, distant objects in space, even if they never actually do, at least can in principle enter into our connected experience; and the same goes for the aftermath of long-ago events (though here we must press the Analogies of Experience more strongly, to cognize that extra "term" of the analogy, via general causality).


[...] the fact that the universe existed long before any perceiving subjects were around[?]

ERROR #1: That is not a FACT.

If "I take away the thinking subject", the biased order of nature introduced by reason ("before") is not anymore possible. From a different standpoint, time being an intuition means that time is a representation. Thus, an orderly representation of nature is necessarily the product of a rational subject; so you are implicitly providing the "fact" of previous existence of a thinking subject, independently of the mistake of calling it a perceiving subject.

Therefore "the universe existed long BEFORE" is NOT A FACT. It is an assumption biased by the time intuition.

ERROR #2: Objects existing as phenomena, and not noumena, is the only possibility for objects to exist. Existence is not an attribute of the noumena; existence is a concept which requires of a thinking subject to be possible.

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