Kant wrote:

... if I remove the thinking subject, the whole material world must at once vanish because it is nothing but a phenomenal appearance in the sensibility of ourselves as a subject, and a manner or species of representation. — Critique of Pure Reason

Given our understanding of physical phenomena and cosmology, we have strong evidence when there was no life on this planet. Presumably this was evident too in Kants time. How does Kant answer this objection?

A similar but more prosaic and quotidian way of putting this - is that there are more than one thinking subject, I see some born and some pass away. That the world no longer exists for a subject that has died is so obvious that Kant cannot mean this. Then what does he mean by the 'whole material world must at once vanish'?

  • I'm not familiar with it, but it seems to me that you are conflating "reality" and "now".
    – user3164
    Jun 4, 2013 at 13:09
  • 4 billion years ago there was no life on this planet. Presumably that point of time was real when time was then - or not? Jun 4, 2013 at 13:42
  • Sure, but we are here now to "observe" the "reality of then". Perhaps that's not too clear, but think of a 3+1 dimensional universe. I just point to the idea that reality is a whole 3+1D space-time (perhaps a block), and not just a 3D space at some "point in time".
    – user3164
    Jun 4, 2013 at 13:53
  • Again I feel compelled to recommend After Finitude! Meillassoux created the concept of the arche-fossil, which might be useful in getting our arms around this problem. (For that matter, some aspects of the argumentation in Brassier's Nihil Unbound seems pretty close to some of this...)
    – Joseph Weissman
    Jun 4, 2013 at 14:37
  • It probably comes under the rubric of the philosophy of time. The only reality we actually have access to - perceptually & sensuously - is now. Times past is elsewhere. Jun 4, 2013 at 14:49

2 Answers 2


This is a longer comment on commando's and your conversation:

Kant's theory has nothing to do with solipsism. It's impossible that there's nothing else out there but our mind because we need to be affected before there is any thought. Nonetheless, as we human beings have no intellectual intuition, we can only perceive things, and what we perceive aren't the things as they are, but only how they are for us. There is no more "for us" when we die, there is no one left to perceive, and ergo the whole world (as it is for us) vanishes.

Of everything else we know nothing. Of course we can think of a time when there was no "us" to perceive things. That doesn't change what people can and cannot know, namely things for us and things in themselves.

  • I agree Kant isn't arguing for solipsism. I agree that noumena exist & cause phenomena, but this is already problematic as existence & causality are intuitions of the mind (if I have the terminology correct - and not concepts). Are you saying Kants theory is mostly about epistemology - and that is how he escapes solipsism? if everyone dies is there still noumena? Jun 5, 2013 at 14:34
  • @MoziburUllah You asked me that before (: Yes, The Critique of Pure Reason is Epistemology, I don't know why that is surprising - Kant says so himself in every preface. I'd say yes to your second question - as we don't know of any dependence between ourselves and the noumena, why would they disappear if we die?
    – iphigenie
    Jun 5, 2013 at 14:40
  • yes, I remember - it ought not to be so surprising! Given Kants distinction between noumena & phenomena I wouldn't identify the world with just the phenomenal realm - which is where I think I got confused. Does Kant use specific terminology to talk about the noumena & phenomena together? Jun 5, 2013 at 15:19
  • @MoziburUllah No, as far as I know there is no hypernym. They are strictly distinguished.
    – iphigenie
    Jun 5, 2013 at 16:17
  • @MoziburUllah By the way, I don't think it is right to say that "noumena cause phenomena". They're just two aspects of one thing, one we perceive, one we don't. I see what you mean by saying that would be problematic. It's simply not the case.
    – iphigenie
    Jun 5, 2013 at 17:01

Some background, skip it if you know it already:

According to Kant, all human beings work like this:

1. There are two types of phenomena: space and time. These are like they are in themselves, and we cannot know them. The eye sees them but cannot understand them, so we cannot know them.
2. These data from the senses will be passed to the categories or concepts. This happens a posteriori. The concepts form the "administration system" of the soul.
3. After combining the phenomena and the concepts, we can know the things. However, because of step 2, we do not know the pure phenomena. We only know how they look for us.

As a side note, this is why he says:

"Thoughts without content are empty, intuitions without concepts are blind."
- Immanuel Kant

You are correct that this means that when you remove the subject, there is no knowable reality anymore. The phenomena might exist, but that subject that has been removed cannot know it, and since he is removed, he cannot know the things like they are to him either.

You have no physical information from the senses about history: you have never been there. That means the image you have of history or the world without humans is purely based on the world as it is now (not as it has been) and fiction. You only have read history books, seen pictures, etc., and all that makes you able to imagine a world like it is described. However, that image of the world does not come from the senses at all. It's fantasy.

The same goes for imagining a world without humans. That isn't based on information from the senses but on fantasy.

This is how these worlds seem to exist in your mind, however they did not come from the senses. Imagining a world without minds is no objection against mind dependent reality because in that case you'd still need your own mind to imagine it. The point Kant makes is that you cannot imagine such a world with knowledge.

Now on the body of your question, which seems to ask a different question.

Kant indeed means that when a subject is no subject anymore, his world vanishes. So the phenomena don't vanish, but the concepts vanish, so that he cannot know the world anymore.

I'm not sure about if Kant thought there would be an afterlife, so I cannot say if this would happen when someone dies.

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