In Paul Guyer's Kant, section "A Life in Work", the author claims this:

this argument from synthetic a priori cognition to the subjectivity of what is cognized is independent of the general premise that whatever is characteristic of sensibility is merely a matter of how things appear to us.

"This argument" is presumably this:

we can have synthetic a priori cognition of the structure of space and time only if we have a priori representations of space and time and indeed only if space and time are nothing but those a priori representations, or the a priori forms of all of our sensible representations of particular objects.

I'm barely understanding why "this argument" is true, although I think I get the general idea of it, and I didn't hope to understand it in depth since we are only in an introductory historical section.

However, Guyer makes that note about the independence of the conclusion to the premise, and I'm thinking that if it is here, it must be important, and it must be intelligible with the tools that I have so far.

So, how is this independence important, and true? Should I be worried about not having a clue why that sentence is here?

  • Wait ... don't tell me, Paul Guyer's a PhD in philosophy? Shows ... He seems ta have noticed a critical aspect of an advocate's MO. I wish him luck (hope he's alive). Juat curious, come to think of it, are all real philosophers like Paul Guyer? I certainly hope they are.
    – Hudjefa
    Commented May 22, 2023 at 10:42

2 Answers 2


Upon writing this question and thinking about it, I could only come to one hypothesis, although I'm not so sure of it:

The "argument" itself mentions "sensible representations of particular objects", but it does not mention anything like "how things appear to us". Although these are apparently the same thing, they are not in more philosophically formal terms. We could take the other route and pose that the sensible representations are the objects, or things in themselves, and Kant up until now does not present a justification why that should not be the case.

  • The sensible representations are the objects (of perception), but the objects differ according to perspective, so they are not things in themselves. Kant seems to consider space and time in a different class; but now we know ordinary space-time is a construct too, one which excludes too-difficult singularities. Commented Jan 22, 2023 at 11:40

Kant's definition of sensibility is a faculty of passive representation, and anything given passively to us "appears to" us, is an appearance. This is apart from whether there are a priori forms of sensibility. Kant says in the "Refutation of Idealism":

From the fact that the existence of external things is a necessary condition of the possibility of a determined consciousness of ourselves, it does not follow that every intuitive representation of external things involves the existence of these things, for their representations may very well be the mere products of the imagination (in dreams as well as in madness); though, indeed, these are themselves created by the reproduction of previous external perceptions, which, as has been shown, are possible only through the reality of external objects. The sole aim of our remarks has, however, been to prove that internal experience in general is possible only through external experience in general. Whether this or that supposed experience be purely imaginary must be discovered from its particular determinations and by comparing these with the criteria of all real experience.

Closer to the other end of the Transcendental Analytic, he says:

Either the object alone makes the representation possible, or the representation alone makes the object possible. In the former case, the relation between them is only empirical, and an a priori representation is impossible. And this is the case with phenomena, as regards that in them which is referable to mere sensation. In the latter case—although representation alone (for of its causality, by means of the will, we do not here speak) does not produce the object as to its existence, it must nevertheless be a priori determinative in regard to the object, if it is only by means of the representation that we can cognize anything as an object.


  1. "Appearances are subjective": a relatively general statement about the passivity of sensibility.
  2. "Formal cognition is a priori": a more particular statement, that the particular sensibility of human beings is conditioned by a priori forms.
  3. "Space/time are forms of a priori cognition as forms of sensibility": the relatively most particular statement (on these terms).

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