Schopenhauer's Criticism of Kant's Analysis of Object
Schopenhauer makes it clear that he is indebted to Kant for his vision of transcendental idealism, and that his Critique of Pure Reason  is a work of genius. However, Schopenhauer argued that Kant made many mistakes when formulating his philosophy, and he set about the task of uncovering them in his Criticism of the Kantian Philosophy, an appendix to be found in The World as Will and Representation . In this essay I wish to analyse the criticism made against Kant's determination of an object, since this is an important factor if we are to comprehend how we understand reality.
Kant's Critique of Pure Reason  is notoriously difficult to read and often unclear. Possibly, this is because Kant was in a hurry to complete the first edition. Schopenhauer comments on Kant's "want of adequate reflection with which he passes over such questions as: What is perception? What is concept? What is reason? What is understanding? What is object?" [1; p.434]. Kant failed to lay down a proper foundation for these fundamental notions, and this has led to ambiguities in his work.
Kant's Theory of Object
Kant gives a summary of the place of objects in our understanding, and how they are perceived, in section 1 of the 'Transcendental Aesthetic' [2; B33 to B36]. He divides all knowledge of objects into intuition and concepts. Objects are presented in intuition, and they are thought using concepts. As an illustration, if I look at a particular chair that I can see in the corner of the room I am in at this moment, it is presented immediately to my intuition as a series of colour and hue sensations occupying the space of my field of vision. As such, it is simply a collection of visual phenomena without any meaning. My understanding is able to spontaneously take these manifold phenomena and synthesizes them to form a concept of the chair. Only with the concept of the chair does the chair become known. Concepts are essential if we are to perceive the world: "in no other way can an object be given to us" [2; B33]. Thus, for Kant, intuition and thought complement one another: "thoughts without content are empty, intuitions without concepts are blind" [2; B75].
The scope of the concept of object goes further than the example I have given immediately suggests: it does not just deal with an object that I perceive at one particular time, but can deal with the object at different times, and at different positions in space. Thus, to take the example of the particular chair I am looking at, the same concept of the chair synthesizes my immediate intuition, along with the chair as it was yesterday when, I recall, it was in another room, and also with any expectation I have of the chair tomorrow. The concept is able to synthesize all of these manifold phenomena across time and space. It picks out those features that make it the same chair; for example, that it is a particular shape and colour, and that it has a particular scratch mark on one of its legs.
Bringing Thinking into Perception
Schopenhauer's first criticism of Kant is that he "brings thinking into perception" [1; p.439]. As we have seen, for Kant, an object is not perceived meaningfully for what it is, until it is thought. Yet, this seems odd, because it seems to me that I do not have to actually think in order to see the chair. There is no need to stop and deliberate on the matter: I simply see the object without any need to think. There is no indication that this is what Kant actually meant, however. Indeed, he talks about the "spontaneity in the production of concepts" [2; B74]. Thus, Kant's intended meaning was that concepts spontaneously and immediately emerge as they appear to intuition: there is no conscious deliberation involved.
Thus it seems to me that this difficulty between Kant and Schopenhauer is one of language. Now, in the twentieth century, and possibly in the nineteenth century when Schopenhauer wrote, the word "think" has a narrow meaning. By "thinking", we usually mean the stream of consciousness that conceptualizes in an abstract way through language and symbols about the world; whereas, perhaps earlier when Kant was writing, it had a broader meaning. Unfortunately, Kant did not leave us a clear definition of his use of the word (and we have already noted the criticism Schopenhauer has for Kant not investigating these fundamental notions adequately). However, we may note that Descartes, for example, used the word "thinking" in a much broader sense, more akin to our modern use of the word "consciousness", as was pointed out in [4; p.45]. Thus Descartes wrote "I seem to see light, hear a noise, and feel heat; this is what in me is properly called perceiving, which is nothing else than thinking" [3; p.90].
Schopenhauer has his own narrow sense of the word "thinking", which becomes clear in his criticism of Kant: "the object of thinking [for Kant] is an individual, real object; in this way, thinking loses its essential character of universality and abstraction, and, instead of universal concepts, receives as its object individual things" [1; p.439]. So, for Schopenhauer, thinking is essentially about abstract concepts. For example, I can think about chairs in general, yet not about one particular chair. Thus throughout his essay, Schopenhauer only talks about perception and abstract concepts, and does not acknowledge the possibility of concrete concepts at all. Yet, this seems to be preposterously wrong, as I think about ordinary individual objects throughout the day. For example, I can ponder about "where did I put my keys?" or "shall I have those sausages for tea, or the pizza I still have in the freezer?" Both questions are thoughts about individual objects.
Thus we see that Schopenhauer has a peculiarly narrow definition of "thinking" which he uses to interpret Kant; then unsurprisingly finds that Kant is in error. The error, it seems to me, is actually in Schopenhauer's reading of Kant.
Schopenhauer gives two pages of references to show that Kant himself was confused on this matter: in one place Kant argued that thinking has nothing to do with perception and then in another states that thinking is essential to perception [1; pp.439-441]. I checked all these references with the desire to uncover such a contradiction in Kant. However, I must say, I found no contradiction worth mentioning. Most of the confusion has occurred through Schopenhauer substituting the more nebulous word "perception" where Kant actually used the word "intuition" , which in the Kantian framework has a very specific and technical meaning. For example, Schopenhauer gives his interpretation of Kant as having written "the categories of the understanding are by no means the conditions under which objects are given in perception" [1; p.440] in [2; A89; B122]. This indeed seems to support Schopenhauer's argument that thinking is not involved in perception; a point which is "contradicted most flagrantly by all the rest of his [Kant's] doctrine" [1; p.440]. However, my reading of this passage is "the categories of understanding do not represent the conditions under which objects are given in intuition". With the word "intuition" instead of "perception", this sentence makes perfect sense, and is in no way contradictory to Kant's doctrine, since it is made quite clear that intuition is separate from the understanding in concepts.
Confusing the Object with the Thing-In-Itself
One real difficulty with Kant's notion of object is that it is difficult to know what exactly Kant thought it was. If he had said that an object was simply the concept (of the object) realized in phenomena, the notion would be quite clear. We could locate the object as representation, as Schopenhauer does. Unfortunately, Kant is ambiguous on this point. Kant writes that "objects are given to us by means of sensibility" [2; B33], but that sensation is an "effect" of objects [2; B34]. Also, concepts merely allow us "to think the object of sensible intuition" [2; B75]. Thus, we find that, for Kant, the object is something that effects sensations, but is not in the sensation, i.e. intuition, itself ; and also, the concept is mere thought of the object, and hence is not the object itself ; nor can we say the object is in any way the combination of intuition and concept.
Since "intuition and concepts constitute the elements of all our knowledge" [2; B74], it follows that if object is in neither of these, it must fall outside knowledge. If the object is outside knowledge, then Kant possibly intended it to be the thing-in-itself. So, when I look at my chair, what I am seeing in sensation and conceiving in my mind is mere representation of the chair, which as an object is beyond this representation, and exists as a chair-in-itself. According to Kant, however, beyond our knowledge of the world there is no form or structure, since space and time are properties of mind used in understanding the world. Thus, any thing-in-itself must lack such form and structure. The very idea of a chair-in-itself is nonsense following this reasoning. In general, by "object" we mean some individual thing that exists spatially and temporally in relation to all other objects. So Kant's notion of object cannot be the thing-in-itself afterall. As it is not representation and not outside representation, Kant's object seems to be in a kind of limbo.
Thus, Schopenhauer criticizes Kant for making what amounts to "a triple distinction: (1) the representation; (2) the object of the representation; (3) the thing-in-itself" [1; p.444] precisely because of the reason given above: we cannot locate Kant's object as representation or thing-in-itself. Yet, "when we reflect clearly, nothing can be found except representation and thing-in-itself" [1; p.444]. Thus, Schopenhauer shows that Kant is in error on this point, and the cause of this is "that he gives no theory of the origin of empirical perception" [1; p.445].
It would seem that Kant was still implicitly thinking of objects existing in the Lockean sense: i.e. as spatial/temporal objects existing quite independently of mind. He was not able to follow through his own reasoning completely, and unfortunately this implicit notion runs counter to Kant's doctrine of transcendental idealism. As Schopenhauer comments, "I believe that an old, deep-rooted prejudice in Kant, dead to all investigation, is the ultimate reason for the assumption of such an absolute object that is an object in itself, i.e., one without a subject" [1; p.442].
Schopenhauer, having understood Kant's error, followed through Kant's reasoning more carefully. Thus, for Schopenhauer, the object is to be found wholly in representation, and there are no literal things-in-themselves. He agreed with Kant that there must be an external world beyond representation, but since it lacks form and structure this world has no duality, and cannot be described as a plurality of separate things-in-themselves [1; section 25].
Subject and Object
We may excuse Kant this error, and simply interpret him to mean that an object is the concept (of object) realized in phenomena, since Kant ascribes empirical reality to these. This is the interpretation made by some of Kant's immediate successors like Fichte. However, for Schopenhauer this would still not be sufficient, since as we have seem, he cannot allow "thinking" and concepts to be part of the perception of objects. As I have suggested, this is partly a problem of language and Schopenhauer is wrong. However, there is a more fundamental reason why he could not agree with this formulation. For Schopenhauer, the characterization of the world into subject and object is basic to our perception of the world. The subject/object duality is the "universal condition of all that appears" [1; p.5]. Thus, for Schopenhauer, when we perceive an object, it is immediately an object set against the subject; whereas, in our Kantian interpretation, the objectivity of the sensation is not immediate, but only occurs through the concept. So, for Kant, objectivity, and hence subjectivity, is a function of conceptualization, and is not a fundamental condition of our understanding, as Schopenhauer has it.
Schopenhauer's important principle of the subject/object "universal condition" cannot allow him to accept the Kantian interpretation. Yet, the conclusion this leads Schopenhauer to is unnecessarily complicated. The Kantian model of phenomena and concept is simple; it clearly divides our understanding along a neat line. However, Schopenhauer is left with a rather awkward distinction between sensation, representation and abstract concept. As has been shown, Kant's doctrine of concept can very adequately account for individual objects as well as general concepts (like cause-effect laws); both types produced by the synthesis of manifold phenomena. There is no need to treat individual objects and general laws as fundamentally different types of knowledge. Schopenhauer, however, is forced to do this because of the subject/object condition that he unnecessarily pre-supposes.
Kant was a philosophical pioneer, who for the first time began to explore the limits of human understanding. His basic message has great merit, which Schopenhauer certainly approved of. However, as a pioneer, much of Kant's work is imprecise and incomplete. Schopenhauer saw part of his task as tidying up Kant's philosophy of transcendental idealism.
With regard to Kant's analysis of object, Schopenhauer argues that concepts have nothing to do with objects. I have argued that this disagreement is partly due to a misunderstanding over the meaning of the word "thinking". But also it is partly due to Schopenhauer's insistence on the "universal condition" of object/subject duality. I do not see the need to formulate this condition since (1) it leads Schopenhauer to an over-complicated division of knowledge and (2) objectivity can be derived from Kant's doctrine of understanding in any case.
However, I believe Schopenhauer was correct to point out Kant's own implicit ambiguity when writing about object, and for making it clear that whatever the object is, it should not be confused with the thing-in-itself.
 Arthur Schopenhauer (1818) The World as Will and Representation Tr. E.F.J. Payne (Dover 1969)
 Immanuel Kant (1787) Critique of Pure Reason Tr. Norman Kemp Smith (Macmillan 1929)
 Rene Descartes (1641) A Discourse on Method Tr. John Veitch (Everyman 1912)
 Guven Guzeldere (1995) 'Consciousness: What it is & how to study it' Journal of Consciousness Studies vol.2, no.1; pp. 30-51