Of the many, weighty sections of the Critique of Pure Reason, Kant’s “Refutation of Idealism” has long attracted the special attention of its interpreters. The attraction is due partly to the fact that it addresses one of the Critique’s most important underlying debates, the dispute between empirical realists and transcendental idealists, but it is also due to the interpretive questions it raises. While no one would claim that Kant is a naive realist regarding our sensory perceptions, perhaps there is room for understanding him as a more sophisticated, transcendental kind of realist—one who takes there to be a specifically phenomenological reality in our experience of the world that would allow us to characterize the contents of our perceptual experience as “reality for us.” Given that Kant is clearly some kind of idealist and therefore committed to the idea that objects in the the world of our experience aren’t simply given to us, but are shaped by our perception of them, it becomes all the more interesting to find him refuting idealism. In what follows an attempt at will be made to understand what he might have been up to.
Contents:
Kantian Transcendentalism and Realism
Let’s begin with an by developing a fuller picture of the idealist position Kant takes himself to be refuting. According to Kant’s own account of it, idealism amounts to the claim that the reality of objects in the “external world,” can be held to be either doubtful or non-existent. Thus, idealism may then take either of two forms:
- In one way, it amounts to the Cartesian argument that any claim to any knowledge, including the existence of objects in the external world is “problematic” since we lack the capacity “to prove, through immediate experience, any existence except our own” (B275).
- But in another sense, which he attributes to Berkeley, idealism advocates for the impossibility of asserting that objects outside our immediate perception exist (contrary to Descartes and Locke) and accordingly that whatever objects appear to us in perceptible space are to be regarded as merely imaginary entities (B274).
In either case, the reality of the “external world” becomes a target for skepticism. But it may be seen that Berkeleyan skepticism, because it is all-encompassing regarding our perception is the one that leads to a “two worlds” view, where the “real world“ is something outside of our perception of the world as we experience it.
The denial of such skepticism would seem to require the dialectical opposite of idealism, some form of realist stance toward objects in the external world. Yet this seems to conflict with Kant’s transcendental approach to knowledge and/or experience. The question arises whether Kant has a solution for skepticism about the external world and whether transcendentalism can accommodate some form of realism.
A Sketch of Kant’s Argument
In setting up his argument for the reality of an object in our perception, Kant begins with the proposition that contrary to Descartes, we can only develop an understanding of the self as permanent by reference to spatially extended objects, since spatiality is the underlying condition for the permanence we experience as belonging to the self.
His argument proceeds as follows. We have a conscious awareness of our existence as “determined in time.” Unpacking this rather leading but unarguable proposition, we find that (1) that we are conscious or aware of ourselves as perceiving a succession of states of perceptive awareness (our empirical self), which, in turn, enables us to perceive (2) that there is something relatively permanent underlying them, our existence, that might be called a “self” or an “I.” But the recognition of the self as a persisting, relatively permanent something within us cannot come merely from reflection upon the self as such, as happens in the Cartesian Meditations. Instead, Kant argues (3) that if the self, taken strictly as an empirical self, is considered as a succession of states of perception, the perception of a permanent can arise only from objects in the world apart from the self that underlies them.
The ultimate basis and perhaps the best justification for this move can be seen to lie in Kant’s transcendental conception of space. Space is a necessary feature of our perception of things about us in the world. But most importantly for our present purposes, it may be understood as the permanent background condition for the perception of the extension of anything (in space) so that there may be any perception of objects at all. It is this permanent, the permanent of permanents, that allows Kant to claim that the origin of our concept of permanence must lie in our perception of the world about ourselves.
So far Kant has been addressing the basis for objects to appear to us as extended objects. But establishing a radical basis for their appearance (as well as for the distance between them) is also part of his strategy for defeating Berkeley’s claim that space is “in itself impossible.” By understanding space as a property of things specifically as we perceive them i.e. not of “external” objects in the original Cartesian sense, Kant’s transcendental approach to the reality of space as the fundamental form of our perception guarantees the reality of space for us.
However, it does not pretend to prove anything about the nature of things in themselves. Kant writes,
Dogmatic idealism is unavoidable, if space be interpreted as a property that must belong to things in themselves. For in that case space, and everything to which it serves as a condition, is a non-entity. The ground on which this idealism rests has already been undermined by us in the Transcendental Aesthetic….”
B274-275
The final remark about the transcendental aesthetic may remind us that the apparent objectivity of objects is only possible in and by our perception, so that the Cartesian sense of an “external” world of the senses becomes an oxymoron. In fact, the problematic notion of an external world collapses into a into the notion of a transcendental reality tied to our experience of the ’I’ as thinking its objects within the framework of the categories and the forms of perception, i.e., of experience in and on the basis of transcendental apperception.
This collapse of the Cartesian “outer” comes in the text as follows. Perhaps surprisingly, with a reversal of the Cartesian assumption about the immediacy of our knowledge of the thinking ‘I,’ Kant writes that while our outer experience is immediate, our inner experience is mediated by our outer experience: our experience of the self as a self determined in time is only possible through outer experience because it is only through our outer experience that we encounter a permanent in space by which we can form a notion of a relatively permanent self underlying the stream of its thoughts and their objects. This transcendental reformation of our understanding of our self awareness is based upon the recognition of an interdependence between the way our cognitive faculties operate and the logical necessity for them to do so.
An Interpretive Crux
Nevertheless, the text does leave us with an interpretive difficulty. Notice that in B275 we find Kant concluding the initial presentation of his case with the following words that appear to indicate that he meant to apply his reasoning to things in themselves:
Thus perception of this permanent is possible only through a thing outside me and not through the mere representation of a thing outside me; and consequently the determination of my existence in time is possible only through the existence of actual things outside me.”
B 275 (Italics appear in original)
His stress on “thing” as opposed to “representation” and his characterization of existing things “outside me” as “actual” appears to leave no doubt that his argument is intended to push us toward a form of realism that applies to things in themselves. In fact, it seems that this must be the case if Kant is really going to prove the “existence of objects in space” to us in a Cartesian sense as a refutation of idealism would seem to require. After all, it was the reality of such things and not merely representations that idealism called into question.
Nevertheless, a conscientious reader of the Critique who has arrived at the Refutation perhaps cannot help but notice that its contents appear to steer us away from realism as it was, at least classically, conceived. Any form of realism he might want to consistently advocate for must be taken as delimited by his own transcendental approach to the actuality of things outside ourselves. How, then, can Kant defeat the idealists on their own ground if his transcendental story about the reality of “things” is in fact mediated by the way in which we represent them to ourselves making even their existence doubtful?
Did Kant actually fall into the trap of thinking that his transcendental arguments proved more than they could? If our perception is not one that attaches to things themselves, and we have no knowledge of things themselves (we cannot even apply the forms of space and time to them) then no consideration of the permanence of the objects in our perception can yield any knowledge of their actual existence. Does this not make the existence of things themselves at least doubtful as Descartes would have it? If doubtful, do Kant’s transcendental arguments provide any assurance that things in themselves exist outside our perception at all?
A Transcendental Solution
The following is, I believe, a solution that reveals a fundamentally important point about Kant’s argument. So far, a dilemma has been raised that challenges the idea that there is a straightforward solution in the Critique to skepticism about the reality of objects in the external world. What I would like to propose is that Kant’s argument is indeed a transcendental one, which is to say that he attempts to reason about the reality of objects in the external world from a transcendental framework within which space and time can be assumed to be the basic forms that shape our perception of the world. But as the foregoing dilemma makes clear, these assumptions aren’t quite enough.
Rather, the key to understanding the true force of Kant’s argument lies in its structure. It will be explained in what follows that it takes the form of a reductio. As such, it trades upon the reality of a conception of the self as containing something permanent relative to the fleeting perceptual states of which it is aware. The significance of this fact for the cogency of Kant’s argument will be made clear in what follows.
Kant’s Argument as a Reductio
Kant’s argument is an argument against the merely illusory nature of reality. That much has been made clear. But it should be emphasized that it is first of all an argument against Berkeley’s conclusion that our perception of objects in space amounts to an illusion. We need to start with Berkeley as a foil to get a sense of what Kant’s argument is initially aimed at disproving.
Their fundamental disagreement comes down to their views concerning the reality of space itself. Since, as Kant writes, Berkeley considers existence in space to be a necessary property of things in themselves (he makes no distinction between things considered transcendentally and as they are in themselves), and since he regards space as “something which is in itself impossible” [B274], he is led to the conclusion that things in themselves are “merely imaginary entities” [B274]. Kant, however, has made a point of avoiding this conclusion since the early pages of the Critique. A foundational element of his transcendental strategy is his move to make space a property of all objects within our perception rather than a property of things in themselves, which he regards as inscrutable since we have an epistemic access to them. This fact alone makes Kant’s refutation unavoidably transcendental, since, as quoted above, he says that the “ground on which idealism rests has been undermined by us in the Transcendental Aesthetic” [B274] and indeed says that “dogmatic” (i.e. Berkeleyan idealism) is unavoidable unless the transcendental turn is accepted.
A sketch of the steps in his argument that highlights its reductio strategy shows the logical basis for accepting the transcendental turn over idealist skepticism:
- Either space is a property of objects in our outer experience, or it is not.
- Suppose with Berkeley that space is not a property of objects in our perception.
- It follows that since space is a necessary condition for the determination of objects in time and the self must be determined in time if it is to be considered permanent with respect to its perceptions, it follows that if (2) is true, then it is incompatible with our everyday experience of the self.
- But suppose instead with Kant that space is a property of objects in our perception.
- It follows that they may then be considered as existing in time.
- Because space itself is a permanent feature of our perception, any object existing in time may be determined in time relative to space as a permanent feature or permanent background feature of objects existing in time.
- Only if 6 is true may we develop a concept of something as existing in time at all.
- The concept of the self, which develops out of our awareness of ourselves as perceiving objects in the world about ourselves, is one such thing.
- Since the reality of space is a necessary condition for our perception of the self as something beyond its perceptions and the objects it perceives as existing in time, it follows that unless we accept (4.) and deny (2.), we will be led to the absurd conclusion that our conception of the self as existing in time is impossible. It is therefore necessary to accept (4.) in order to avoid (3.).
This sketch allows for a proper recognition of a further important element of Kant’s argumentative strategy: only by arguing from the reality of objects existing in space is it possible to provide a basis for the recognition of the self as existing in time.
Since both Descartes and Berkeley attempt to argue from the self and its self-awareness rather than from the assumption that objects really so exist in space, they are unable to arrive at conception of the self as a form of conscious self-awareness that persists along with the flow of perceptions of which it is aware. As mentioned above, the cogency of Kant’s argument hinges upon the degree to which (3.) is a necessary but absurd, unacceptable conclusion if the premises that lead up to it are accepted. If we decide that in order to avoid (3.) we must accept (4.) we are driven to the conclusion that we must accept the proposition that objects exist in space if we are to retain our conception of the self. Only if we accept that perceptual objects exist in space may we retain our notion of the self as something permanent relative to its perceptions.
This brings us closer to a fuller grasp of what Kant is gesturing toward when he speaks of turning the game idealism plays against itself. He turns the tables on idealism by showing that only by accepting a transcendental notion of the reality of objects in our perception may we retain the notion of the self their own argument assumes to be true and argues from as something axiomatic. Both Descartes and Berkeley begin with the self-subsistent nature of the self as a self-evident assumption. But Kant shows that if that point is retained, the only way to do so is by accepting the transcendental turn that undermines their conclusion that the reality of objects is either doubtful or illusory.
The force of the only if can be construed as putting anyone who wants to argue against the illusory nature of external objects in this bind. Perhaps this is why he does not linger very long over the problem of distinguishing our everyday experience of reality from what we experience perceptually in dreams in his Note 3. He feels the force of his argument to be sufficiently binding upon the skeptical idealist that anyone who takes up that position must fall into an absurdity to which their own argument compels them.
The Reality of Objects in our Perception
This way of considering the strength of Kant’s argument brings us to a point where not only its analytic-logical force can be appreciated, but also its ontological aspect, the way in which it applies to the existence of things and the manner in which they exist. Perhaps the most straightforward answer from the text itself regarding the way in which Kant regards his argument to indeed apply to the reality of things and not merely their representations appears in B278:
From the fact that the existence of outer things is required for the possibility of a determinate consciousness of the self, it does not follow that every intuitive representation of outer things involves the existence of these thing, for their representation can very well be the product merely of the imagination.”
When read together with the text quoted above from B275 (where the “dilemma” was discussed) a case emerges for how it should be read. Kant regards our recognition of the existence of the self as a “determinate consciousness” as requiring the existence of objects in our experience (see the first line of the text quoted immediately above). This indicates that where Kant distinguishes the actuality of objects from their representations above in B275 he should indeed be read as regarding the everyday objects of our perception as fully real-except in cases where they may be considered products of our imagination.
This conclusion can be considered a further consequence of the bind into which he believes the idealist is drawn by the force of his argument. It may however be its weakest link. Suppose that because of the manipulations of an evil genius all of one’s perceptions of permanence are merely illusory. It does not appear to make any difference to the formation of a concept of permanence whether they are genuine or merely illusions of reality. In other words, even if all my perceptions really are mere illusions, even within a transcendental framework, it would still be possible to form a concept of a relatively permanent self on the basis of those illusory perceptions of permanence. The illusory non-existence of everyday objects we perceive as existing would then be equally compatible with the existence of a determinate self.
The response open to Kant would be to say that in that case “reality” in so far as I can experience it would just be our reality and the reality that would justify a determinate self. Perhaps this level of hyperbolic skepticism cannot be defeated by such an argument, but nevertheless would leave us in much the same position in terms of how we may regard our relationship to objects in our perception. Considering his argument in this light makes clear that Kant regards the existence of objects to be genuine and actual whatever might be said for things as they are in themselves and his argument does lead us toward conclusion that we must turn away from any consideration of things themselves as the basis for our reality if we are to retain a sense of the determinate reality of the self.
This point brings us to the following conclusion: perhaps the most defensible version of the Refutation would be one that understands Kant as moving the basis for his refutation away from the question of the reality of things as they are in themselves altogether toward the higher ground of basing the reality of things as they appear to us upon our everyday perception. The fact that for Kant space and time are necessary forms of our perception within the transcendental framework means that, if it is accepted, space and time attack to all such objects as part of their reality whether they appear in dreams or as part of our waking conscious awareness. It then becomes impossible to argue with Berkeley that the reality of everyday objects can be doubted because space may be merely a perceptual fiction. In fact, the only perceptual reality there can be for us is one that requires objects to appear in space, in time. This is the reality Kant takes to be our reality and he argues from that reality rather than toward the reality of things in themselves.
Finally, Kant acknowledges the philosophical soundness of the kind of skeptical argument “problematic” (i.e. Cartesian) idealism makes:
Problematic idealism,…which merely pleads incapacity to prove, through immediate experience, any existence except our own, is, insofar as it allows of no decisive judgment until sufficient proof has been found, reasonable and in accordance with a thorough and philosophical mode of thought.”
B275
Kant’s rejoinder is of course that our experience of the self as determinate in time is mediate and requires an immediate experience of the world about us. That perceptual reality must be present if we are to have any notion of the Cartesian self. But as we have seen, that perceptual reality need not be considered one that is applicable to the reality of things in themselves–even where their existence is concerned. The kind of realism Kantian transcendentalism leaves us with is one that takes the reality of objects about us to be defined not by the reality of things in themselves, but by the forms that condition of our perception.
