Monthly Archives: March 2012

Is Kant’s Model of Transcendental Idealism a Defendable Notion?

Before deciding whether transcendental idealism is a defensible viewpoint, transcendental idealism must first be defined, and separated from the other forms of idealism so that a better understanding of what it proposes can be obtained. Then it needs to be compared to other forms of idealism to see, of the different forms of idealism, whether it can be defended as a valid idea. After this it shall be subjected to three forms of realism to see if it can stand up to the traditional opponent of idealism. I am confident that transcendental idealism, when properly understood and argued, will not only be shown to be a defensible notion, but show that it is fully capable of revealing the other forms of idealism and all kinds of realism to be untenable in comparison.

To begin with definitions are in order, so what, exactly, is idealism? Idealism is the view that ‘the physical world exists either only as an object for mind, or only as a content of mind, or only as something itself somehow mental in its true character’ (Sprigge, 1998). That is to say that the world of our sensations, or outer sense, is to a greater or lesser degree mind-dependant. It is the degree of dependency the physical world has to the mind that is under dispute in idealism. Some like George Berkeley claim that only two kinds of things exist, minds and ideas, and that the physical world is nothing more than a collection of ideas in the form of sense data. Others, like Kant, (2007) would strongly argue against this as they claim that whilst our sense experience relies on the synthetic a priori truths of space and time which are reliant on our minds, what we sense as physical objects are only ‘mere impressions’ and not what they are as things-in-themselves [A 491].



As for the definition of ‘transcendental’ in this context, Kant gives it to us earlier on in the ‘critique of pure reason’ at [A 12] where he says: “I entitle transcendental all knowledge which is occupied not so much with objects as with the mode our knowledge of objects in so far as this mode of knowledge is to be possible a priori.” According to this, then, transcendental idealism concerns our minds and their cognitive operations, its functions and limitations. This is as opposed to the mistaken impression that some could make that by transcendental he meant to make claims of things beyond our scope of understanding, for he makes no claims about the nature of things-in-themselves, other than the fact that they exist as things-in-themselves in so far as they are things-in-themselves [B xxvi]. With this understood, Kant’s transcendental idealism shall now be compared to other forms of idealism to see if it is defensible in that regard.

First up is the ontological (or dogmatic) idealism of Berkeley (Sprigge, 1998). Expanding on what has been said on this earlier, there are two reasons why Berkeley believed the physical world was made up of ideas. The first claim is that the only way we can have empirical evidence for the existence of physical objects is if these objects are conceived as collections of ideas which cohere in experience. The second assertion is that both primary and secondary qualities of objects are mind-dependant, as the factors that make the apparently secondary qualities mind-dependant can equally be said to be valid for claiming the same for primary ones. The challenge transcendental idealism has to deal with here is this, if these two reasons given by Berkeley are true, as far as we can make out, is not the idea that there might be something beyond our senses  which is responsible for ‘appearances’ that lies outside of our minds as a thing-in-itself merely multiplying entities beyond their necessity?


Kant would say not for, whilst agreeing with the second claim in so far as they regard ‘mere impressions’, it being something that needs both our sense experience that requires the a priori intuitions of space and time, and concepts that require the logical function in judgements and categories of our faculty of understanding. He would disagree that things-in-themselves are objects, ‘Without sensibility no object would be given to us, without understanding no object could be thought’ [A 51] for something to be an object for us it requires both the intuitions and the concepts, therefore the things-in-themselves are not objects.

Kant doesn’t claim that they are objects, for nothing can be said of things-in-themselves other than they can be thought [B xxvi – B xxvii], so to say there is a multiplication of entities is false because rather than there being ‘appearances’ and things-in-themselves as two separate ‘things’, one exists and the other is the ‘mere impression’ of the thing-in-itself upon our minds. As time and space are intuitions they are mind-dependant and they and the things that rest upon them cannot be part of what things-in-themselves are, so things-in-themselves bear no resemblance to the ‘mere impressions’ whilst at the same time being the same entity.  Kant asserts that we can know that things-in-themselves exist, and that there are more than just minds and their ideas. To do this he takes ‘time’ which both he and Berkeley would agree exists in the inner sense (for Berkeley ALL that exists resides in the inner sense), and puts forward the following two arguments:

Firstly, I am aware of myself as being in time. Being in time presupposes something permanent perceptionally. But this permanence cannot come from me because my existence in time relies upon this permanence. Therefore my perception of this permanence is only possible because of a ‘thing’ outside of me, not an ‘appearance’ of a thing outside me which means that my awareness of being in time is possible only because there are actual things I perceive outside of me. Secondly, that my awareness of being in time is linked by necessity of being aware of the possibility of being in time. Therefore it is linked by necessity to the existence of things outside of me as the state of being in time, which means the awareness of my own existence is at the same time a direct awareness of the existence of other ‘things’ outside of me [B 276].

This not only defends transcendental idealism against Ockham’s razor, but eliminates the idealism of Berkeley, as it shows there is more than just minds and ideas, and gives a good case for the existence of things-in-themselves. Another form of idealism is the problematic idealism of Descartes [B 274 – B275], who argues that objects outside of us in space cannot be proven, as we are unable to prove anything outside of our direct experience, which is that of the ‘cogito’ or inner sense. This is equally defeated by the above argument as it shows that our inner experience of the ‘cogito’ is only possible if we presuppose the experience of objects outside of us in space.

Next up are the varying kinds of ‘realism’, but what is meant by realism, and how is opposed to idealism? Well realism (Craig, 1998) is the belief that everything about our sense experience, or outer sense, is mind-independent and that what we see, hear, taste, touch and smell is the world as it really is. As all idealism relies upon some element of mind-dependence, they are opposed in regards to our minds and sense experience. There are three main variations of realism that shall be tackled, naive (or direct), representative (or indirect), and transcendental realism, these shall be explained below.

Naive (or direct) realism (Heil, 2006) is the view that we perceive things as they really are. That the properties that we find are mind-independent – colour, shape, taste and such are direct properties of the perceived objects themselves. Direct realism claims that there is no noumenal realm of things-in-themselves, as what we see are things-in-themselves. It is considered epistemically direct, but does not have to be causally direct in nature.

Representative (or indirect) realism (Dretske, 2006) is the idea that whilst there is a world of mind-independent objects, we don’t directly perceive them, we only directly perceive the effects of these objects upon us. As opposed to direct realism we don’t see things-in-themselves, but whereas transcendental idealism makes a similar claim, indirect realism differs by stating that what we perceive in the effects of these objects upon us are actually the properties that things-in-themselves possess.

The final kind of realism that shall be looked at is transcendental realism (A 369). Transcendental realism is put forward by Kant as the opposing transcendental view. This differing outlook states that both time and space are independent to our sensibility, and that outer experiences are to be considered things-in-themselves and also exist independently of our senses. Because of this they are outside of our pure concepts of the understanding.

Kant has a response to each of these forms of realism corporately, as they all possess the common thread of declaring time and space to be outside of our minds, and inherent in the objects of our outer experience, conversely this is one contention that they all have in common against transcendental idealism as it holds the diametrically opposed view that time and space are indeed internal to our minds. To defend transcendental idealism against these forms therefore, it shall be shown in two arguments why time and space are internal to us, and how realism is an absurd notion.

The first argument shows how space and time can be seen as internal to us, and is proposed like this: The existence of myself (and hence my inner state) is necessary because I am self aware [B 55]. Self awareness of my inner state is only possible if objects outside of me are presupposed. Before objects can be cognized time and space must be presupposed. If time and space are presupposed before experiencing objects of outer sense, then time and space are a priori. If a priori, then they are pure forms of sensible intuition. ‘The understanding can intuit nothing and the senses can think nothing’ [B 76], therefore to perceive objects requires both pure forms of sensory intuition and concepts. I am aware of external objects both conceptually and intuitionally, therefore time and space are internal to me

This second argument shows how if time and space are assumed to be external to us it can lead to absurdity [A 369]. For, if time and space are eternally self-existent entities outside of us that include everything within them, then outer appearances are things-in-themselves. If outer appearances are things-in-themselves, then they exist outside of our sensibility. If they exist outside of our sensibility, then they exist outside of the pure concepts of understanding. If we lack the sensibility and concepts of outer appearances, then we cannot know them. If we cannot know outer appearances, then we can only know inner appearances. If we can only know inner appearances, then we can only know our minds and its ideas. If we say we can only know our minds and ideas, then we are dogmatic idealists. If we claim to be dogmatic idealists, then time and space cannot be eternally self-existent entities outside of us that include everything within them.

If however, you argue that time and space is outside of us but subsists within objects [B57], then time and space can only be seen as relations of objects of outer sense. If only as relations of objects of outer sense, then these relations can only come about through experience. If only through experience, then a priori systems such as mathematics or geometry cannot be used to understand objects of the outer sense. We can understand objects of the outer sense with geometry or mathematics; therefore time and space do not subsist in objects. As you can see, when both arguments are brought to their conclusion both of the possible ways that time and space can be outside us are shown to be flawed, either it denies itself, or denies the self evident.

In conclusion, I would say that of the viewpoints expressed within this essay, transcendental idealism has shown itself to be the superior. In regards to Dogmatic and problematic idealism, it showed that our inner experience is only possible if we presuppose the experience of objects outside of us in space and successfully tackled the claim that it was falling foul of Ockham’s razor. In regards to naive and representational realism, it showed their claim that time and space is found within objects to put into question the far more self evident truths of mathematics and geometry with respect to our outer experience. Finally in regards to transcendental idealism, it showed that by claiming that time and space were eternally self-existent entities outside of us it self-refuted itself by unpacking through argument into a form of dogmatic idealism. Considering all this, I think that you will agree.


Craig. E, (1998), Realism and antirealism. In E. Craig (Ed.), Routledge Encyclopedia of Philosophy. London: Routledge.

Dretske, F. (2006). Perception. In:  Audi, R. (Ed.) The Cambridge Dictionary of Philosophy. 2nd ed. New York: Cambridge University Press. P654-658

Heil, J. (2006). Direct Realism. In:  Audi, R. (Ed.) The Cambridge Dictionary of Philosophy. 2nd ed. New York: Cambridge University Press. P237-238

Kant, I. (2007). Critique of Pure Reason. (Trans: Smith, N.K.  2nd ed.) U.K: Palgrave Macmillan.

Sprigge, T.L.S. (1998). Idealism. In E. Craig (Ed.), Routledge Encyclopedia of Philosophy. London: Routledge.

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