"Critique of the Kantian philosophy" (German: "Kritik der Kantischen Philosophie") is a criticism Arthur Schopenhauer appended to the first volume of his The World as Will and Representation (1818). He wanted to show Immanuel Kant's errors so that Kant's merits would be appreciated and his achievements furthered.
At the time he wrote his criticism, Schopenhauer was acquainted only with the second (1787) edition of Kant's Critique of Pure Reason. When he later read the first (1781) edition, he said that many of Kant's contradictions were not evident.
Kant's merits
According to Schopenhauer's essay, Kant's three main merits are as follows: The distinction of the phenomenon from the thing-in-itself (Ding an sich) The intellect mediates between things and knowledge Locke's primary qualities result from the mind's activity, just as his secondary qualities result from receptivity at any of the five senses A priori knowledge is separate from a posteriori knowledge The ideal and the real are diverse from each other Transcendental philosophy goes beyond dogmatic philosophy's "eternal truths", such as the principle of contradiction and the principle of sufficient reason. It shows that those "truths" are based on necessary forms of thought that exist in the mind. The explanation of how the moral significance of human conduct is different from the laws that are concerned with phenomena The significance is directly related to the thing-in-itself, the innermost nature of the world Religious scholastic philosophy is completely overthrown by the demonstration of the impossibility of proofs for speculative theology and also for rational psychology, or reasoned study of the soul
Schopenhauer also said that Kant's discussion, on pages A534 to A550, of the contrast between empirical and intelligible characters is one of Kant's most profound ideas. Schopenhauer asserted that it is among the most admirable things ever said by a human. The empirical character of a phenomenon is completely determined The intelligible character of a phenomenon is free. It is the thing-in-itself which is experienced as a phenomenon.
Kant's faults
Fundamental error
Perceptions and concepts
Kant wanted to make the table of judgments the key to all knowledge. In so doing, he was concerned with making a system and did not think of defining terms such as perception and conception, as well as reason, understanding, subject, object, and others.
Fundamental error: Kant did not distinguish between the concrete, intuitive, perceptual knowledge of objects and the abstract, discursive, conceptual, knowledge of thoughts. Kant began his investigation into knowledge of perceived objects by considering indirect, reflective knowledge of concepts instead of direct, intuitive knowledge of perceptions. For Kant, there is absolutely no knowledge of an object unless there is thought which employs abstract concepts. For him, perception is not knowledge because it is not thought. In general, Kant claimed that perception is mere sensation. In accordance with Kant's claim, non-human animals would not be able to know objects. Animals would only know impressions on their sense organs, which Kant mistakenly called perception. Kant had erroneously asserted that full, perceived objects, not mere sensations, were given to the mind by the sense organs. Perception, however, according to Schopenhauer, is intellectual and is a product of the Understanding. Perception of an object does not result from the mere data of the senses. It requires the Understanding. Therefore, if animals do not have Understanding, in accordance with Kant, then they have only Sensation, which, Schopenhauer claimed, gives only raw sense data, not perceived objects. Schopenhauer considered the following sentences on page A253 of the Critique of Pure Reason to encapsulate all of Kant's errors: If all thought (by means of categories) is taken away from empirical knowledge, no knowledge of any object remains, because nothing can be thought by mere intuition or perception. The simple fact that there is within me an affection of my sensibility, establishes in no way any relation of such a representation to any object. On page A253, Kant stated that no knowledge of any object would remain if all thought by means of categories were removed from empirical knowledge. Schopenhauer claimed that perception occurs without conceptual thought. On page A253, Kant stated that a concept without an intuition is not empty. It still has the form of thought. Schopenhauer claimed that perceived representations are the content of a concept. Without them, the concept is empty.