A novice, I do not feel prepared yet to, but shall in future, read Kant; please tell me if Kant's originals answer my question.
Source: p 256, Think: A Compelling Introduction to Philosophy (1 ed, 1999) by Simon Blackburn

Kant's revolution is introduced in a famous passage at the beginning of the Critique of Pure Reason:

Hitherto it has been assumed that all our knowledge must conform to objects. But all attempts to extend our knowledge of objects by establishing something in regard to them a priori, by means of concepts, have, on this assumption, ended in failure. We must therefore make trial whether we may not have more success in the tasks of metaphysics, if we suppose that objects must conform to our knowledge. This would agree better with what is desired, namely, that it should be possible to have knowledge of objects a priori, determining something in regard to them prior to their being given. We should then be proceeding precisely on the lines of Copernicus' primary hypothesis. Failing of satisfactory progress in explaining the movements of the heavenly bodies on the supposition that they all revolved round the spectator, he tried whether he might not have better success if he made the spectator to revolve and the stars to remain at rest.

[1.] A similar experiment can be tried in metaphysics, as regards the intuition of objects. If intuition must conform to the constitution of the objects, I do not see how we could know anything of the latter a priori; but if the object (as object of the senses) must conform to the constitution of our faculty of intuition, I have no difficulty in conceiving such a possibility.

This is the element that Kant calls "transcendental idealism". He is very keen that it is not the "subjective idealism" of Berkeley. And obviously, it cannot be the "transcendental realism" of Locke. So what is it?

How do you achieve or realise 1 (this new method of thought and perception for daily life)? The above translation and Blackburn do not exemplify or advise how to try it in practice.

3 Answers 3


Broadly speaking Kant argues against the view that our intuition is shaped by the external objects. Instead he advocates to revert the view: Our intuition shapes how we register external objects. The passage is from Bxvi of Critique of Pure Reason (CPR).

Intuition is one of Kant's main technical terms. The two forms of intuition are space and time. Kant explains them in more detail in the beginning "Transcendental Aesthetic" of CPR. Space and time are not properties of the external objects; they are the means by which we observe external objects.


When Kant writes, "A similar experiment can be tried in metaphysics..." he is referring to what he is about to do in the CPR, namely, elucidate a theory that explains how we can have a priori knowledge of objects. He is not describing some kind of mental feat.

Transcendental realism (borrowing Kant's terminology) is the philosophical stance that there is a material, external world, but that we cannot have knowledge of it. At best, we can only guess what it is like based on the data we receive from our senses. (For all we know, we're brains in vats.)

Subjective idealism is the philosophical stance that there is no material, external world. Things like tables and chairs are just ideas in our minds that would not exist without minds to perceive them.

Kant's transcendental idealism is the philosophical stance that there is a material, external world and we can have knowledge of it -- with serious caveats. Our minds automatically organize the chaos of existence into a governing framework. Just in the way our eyes interpret light, our minds interpret reality. According to Kant, our minds interpret the world by translating it into space and time; another sort of being (say, God) would not necessarily perceive reality as spatial or temporal. Thus, Kant believes we can have knowledge of the world because our minds play an active, automatic role in "constructing" it (translating it into space and time). However, he grants the possibility that there are aspects of reality (possibly whole objects) that do not get "translated" and he does not believe we can have any knowledge of those (what he calls "noumena").

The above is, of course, a gross over-simplification. When you do dive into Kant, I recommend the Routledge Philosophy Guidebook to Kant and the Critique of Pure Reason.


First, in regard to your "how to" question. It is virtually impossible to "get" Kant the way you might "get" a mathematical solution or "translate" a word. Many describe learning Kant as a slow immersion in his intricate terminology and its whole way of relating and describing the world. Nothing mystical, just like learning a language.

Two key Kantian terms are Intuition and Concept. They correspond very roughly to "particular contents" and "general forms," in that they always operate interdependently. Together they refer to "objects" of, for example, propositions or judgments.

But... they do not simply "refer." The "objects" are not simply "out there" making an impression "in here." Nor do we ever have direct and immediate access to these "things" as they are purely "in themselves." They are not simply "present." We make them present. We "represent" them to ourselves.

How? By our mental faculty of using Intuitions and Concepts. The Intuitions give us the singular, particular "sense" of "something." The Concepts, such as "red" or "square" organize the intuitions into general sets that can be mentally "moved about" and related.

This dual process brings about the objects or "things" that appear to our minds. (Indeed, whatever is in our mind is a kind of anchored "appearance," though this does not mean a floating "illusion.") What these appearing things are "outside" of this mental operation cannot be known...just as we cannot know the pure "real" flavor of an apple without the "interference" of chewing and tasting.

So in [1], Kant's "experiment" is to turn around the usual idea of our intuitions "receiving" the sense impression of "something" out there, to which intuitions "conform." After this turnaround, how could we "form" concepts about our intuitions? How could we say, for example, all these various particular sensory intuitions are "apples"?

However, what if we turn around the idea of intuitions "receiving" senses? Instead, we think of our faculty of Intuition as forming or "chewing" something so Intuition can fit into our Concepts and thus be processed or "digested," to stretch the metaphor, by our faculty of cognition.

This "turn" Kant likens to Copernican theory, which made Galileo, Newton, and modern science possible. It is often described as centering "cognitive motion" on the "subject" as Copernicus centered planetary motion on the sun.

The main shift is to see that "motion" is relative. What is fixed and what is moving depends on the location you define as "central." In the complex cognitive motion of intuited "senses" Kant centers the process on objects "formed out of intuitions" rather than intuitions "conforming to" objects.

Standard Kantian Disclaimer: All of the above is gross oversimplification for which the writer shall not be held liable.

  • Thanks. I know that the above grossly oversimplifies, but can you please clarify 5th last paragraph (counting your Disclaimer as the 1st last paragraph)? Before any turn of thought, humans think via Intuition<sub>1</sub> and Conception<sub>1</sub>; but then after the turn of thought, does Intuition<sub>1</sub> become Conception<sub>1</sub>? If so, what happened to Conception<sub>1</sub>? If not, then how does Intuition<sub>2</sub> differ from Conception<sub>1</sub>?
    – user8572
    Feb 7, 2016 at 0:04
  • Would you please respond in your answer, which is easier to read than comments?
    – user8572
    Feb 7, 2016 at 0:05
  • @LePressentiment. That is a very good question. It is one that has been asked and debated, even today, by Kant scholars. As a total amateur, I can only give my sense of things. No one has a problem with "concepts" and no one has a problem with the "input" or "intuition" of sensations. The problem lies in what this "intuition" is. Is it some chute which just dumps the "energy" of some external "object" into the brain or mind? Kant says no. It is more like a muscle. It has already "chewed" whatever can "appear"to us. So, the crucial point is this... Feb 7, 2016 at 4:24
  • ...to continue. Kant, in his era, wanted to point us away from constantly looking "out there" for the truth. But nor can we look "in here" for the truth. His solution entails that...well, we cannot find "the truth," in the old fashioned sense. We just drop that program. So, what "appears," everything we can "sense," is limited by... what? Good question! By God? By matter? Kant's answer is by how we can "make sense" of things. Feb 7, 2016 at 5:33
  • Thanks again. I tried to disambiguate your pronouns 'it'; please change my edit if I failed.
    – user8572
    Feb 12, 2016 at 21:12

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