Schopenhauer's criticism of Kant's schemata is part of Schopenhauer's criticism of the Kantian philosophy

Schopenhauer's criticism of the Kantian philosophy

Schopenhauer appended a criticism to the first volume of his The World as Will and Representation. He wanted to show Kant's errors so that Kant's merits would be appreciated and his achievements furthered....

 which was published in 1819. In the appendix to the first volume of his main work, Arthur Schopenhauer

Arthur Schopenhauer

Arthur Schopenhauer was a German philosopher known for his pessimism and philosophical clarity. At age 25, he published his doctoral dissertation, On the Fourfold Root of the Principle of Sufficient Reason, which examined the four separate manifestations of reason in the phenomenal...

 attempted to assign the psychological cause of Kant

Immanuel Kant

Immanuel Kant was a German philosopher from Königsberg , researching, lecturing and writing on philosophy and anthropology at the end of the 18th Century Enlightenment....

's doctrines of the categories

Category (Kant)

In Kant's philosophy, a category is a pure concept of the understanding. A Kantian category is a characteristic of the appearance of any object in general, before it has been experienced...

 and their schemata

Schema (Kant)

In Kantian philosophy, a schema is the procedural rule by which a category or pure, non-empirical concept is associated with a mental image of an object...

.

From pure intuitions to pure concepts

Schopenhauer claimed that Kant had made an important discovery. This was his realization that time and space are known by the human mind (Gemüt) apart from any worldly experience. In fact, they are merely the ways that the mind organizes sensations. Succession is time. Position, shape, and size are space. The pure forms of time and space are the basis of the perceptions that constitute experience of objects in the external world.

According to Schopenhauer's psychological hypothesis, Kant "… aimed at finding for every empirical function of the faculty of knowledge an analogous a priori function … ." Kant's tacit reasoning was similar to the following: "If pure intuition is the foundation of empirical intuition, then pure concepts are the foundation of empirical concepts." From this symmetrical analogy, Kant claimed that the human mind has a pure understanding, just as he had previously claimed that the mind has a pure sensibility. This pure understanding, according to Kant, consists of pure concepts or categories which allow the mind to discursively think about the objects that are intuitively perceived as being arranged in time and space.

Using intuitions to substantiate concepts

Kant wrote that "To demonstrate the reality of our concepts, intuitions are required." Since empirical concepts are derived from perceptions, examples of the intuitive perceptions can be used to verify the concept. Kant asserted that pure concepts, or categories of the understanding, can also be verified by inspecting their intuitions or schemata. "If the concepts are empirical, the intuitions are called examples: if they are pure concepts of the understanding, the intuitions are called schemata." Schopenhauer described the use of examples in the following way:

Pure concepts and the pure intuitional form of time

Kant preferred to create arrangements in symmetrical, analogous tables or lists. For Kant, the symmetrical analogues of empirical examples are the a priori schemata. But, in the case of pure concepts and their schemata, how could a reference be made to intuitive perceptions? Schopenhauer declares that concepts a priori "… have not sprung from perception, but come to it from within, first to receive a content from it. Therefore they have as yet nothing on which they could look back [for verification]. The only intuition that a priori concepts can be referred to is the pure intuitional form of time, according to Kant. Time, the mind's ability to know succession, is the only content of a pure, a priori concept of the understanding, or category. "The schemata," he wrote, "therefore are nothing but determinations of time a priori according to rules … .".

Kant's use of symmetrical analogy

Schopenhauer's criticism of Kant's schemata was done, according to him, to help solve the mystery of Kant's way of philosophizing. He tried to show that "… after the happy discovery of the two forms of intuition or perception a priori (space and time), Kant attempts, under the guidance of analogy, to demonstrate for every determination of our empirical knowledge an analogue a priori, and this finally extends in the schemata even to a mere psychological fact. Here the apparent depth of thought and the difficulty of the discussion merely serve to conceal from the reader the fact that its content remains an entirely undemonstrable and merely arbitrary assumption."
Empirical concepts are ultimately based on empirical perceptions. Kant, however, tried to claim that, analogously, pure concepts (Categories) also have a basis. This pure basis is supposed to be a kind of pure perception, which he called a schema. But such an empiricist analogy contradicts his previous rationalist assertion that pure concepts (Categories) simply exist in the human mind without having been derived from perceptions. Therefore they are not based on pure, schematic perceptions.