Kant’s Critique of Pure Reason: A Summary
According to the Kantian project, whose goal is to make a critique of reason, Kant has to answer four questions. The first is, “What do I know?” This question is answered in the Critique of Pure Reason. Rationalism and empiricism are the two philosophical currents that predominated in the seventeenth and eighteenth centuries. Rationalism, on the basis of innate ideas, and empiricism, encrypting the source of our knowledge in experience, conclude with Hume, who argues that we cannot strictly know anything about reality (skepticism).
Kant founded criticism, and lies between these two philosophical trends, arguing that our understanding has certain a priori concepts not derived from experience. He says the limits of knowledge are experience. In the preface to the Critique of Pure Reason, Kant is interested in the problem of the possibility of metaphysics as science. There are two features that make one suspect the possibility of metaphysics: the first is that metaphysics does not progress, or even goes backward, and the second is that there is no unanimity among its supporters.
Conditions for the Possibility of Science
To examine this, Kant establishes under what conditions science is possible. There are two types of conditions:
- Empirical conditions that are particular (affecting individuals or subjects) and contingent.
- A priori conditions, which are universal (valid for all subjects and objects) and necessary.
Kant studies the a priori or transcendental conditions (so named because they belong to the structure of the subject and allow for experience). Kant, therefore, raises the question of under what a priori or transcendental conditions judgments are possible in science. Kant divides the trial basis of two criteria: the relationship between subject and predicate distinguishes analytic judgments (in which the predicate is included in the subject) and synthetic judgments (in which the predicate is not included in the subject).
Secondly, attending to how we know their truth, we can distinguish between subsequent trials (in which I discover their truth through experience), which can be private or not strictly universal and contingent, and a priori judgments (which I did not discover their truth through experience), which are universal and necessary. Combining the two classifications obtained a priori analytic judgments (in which the predicate is included in the subject and not discovered through experience, but have been and will always be so), synthetic judgments a posteriori (in which the predicate and the subject are separated and I discover through experience), and synthetic judgments a priori (in which the predicate is not included in the concept of the subject, I need the expertise to discover them). These trials are the key judgments of science.
Kant’s Copernican Revolution
The question of the conditions that allow synthetic judgments of science is answered in Kant’s Copernican revolution. Hume distinguishes between two types of knowledge: the relations of ideas, which accounts for mathematics, and matters of fact, which bears the physical and ordinary life. Hume thinks that only in mathematics are a priori judgments possible. Kant believes that it is possible to make synthetic a priori judgments, and the possibility to justify attempts a revolution: the Copernican revolution of Kant. It states that the object must conform to the subject; the subject is not active. He argues that it is possible to have a priori knowledge, distinguishes between phenomena (everything has a cause) and noumena (there is Liberty). He also claims that the unconditioned is conceivable without contradiction. In the doctrine of knowledge in the Critique of Pure Reason, he makes a distinction between two faculties of knowledge: sensitivity and understanding.
Transcendental Doctrine of Elements
Within the understanding, Kant distinguishes two functions: to make judgments (later called understanding in the strict sense) and link trials (right calls it). His Critique of Pure Reason is divided into two parts: the transcendental doctrine of elements (divided in turn into transcendental Aesthetic and transcendental Logic) and the transcendental doctrine of method. In the Transcendental Aesthetic, he begins with sensitivity, which distinguishes the feeling (indeed occurred in our sensitivity to the objects). Called sensitivity to the ability to sense perceptions is passive and has two types: external sensitivity (received representations from the outside) and internal (received representations from our minds and our mental contents).
Intuition is the way in which our knowledge relates immediately to objects; humans have only sensible intuition. Types: pure and empirical. There are two ways a priori in our sensibility: space and time, which are a priori forms of sensibility (above and independent structures to experience), intuitions, pure and transcendental conditions of sensory knowledge.
Phenomenon and Noumenon
The phenomenon is the object of an undetermined empirical intuition, as Kant is made of matter (coming from the feel) and form (space and time). When asked if a priori synthetic judgments of mathematics are possible, Kant responds that time is the ultimate foundation of arithmetic, and space of geometry. Mathematics made judgments about space and time, and as these are a priori, so are those.
In the Transcendental Analytic, we find understanding. Understanding is the faculty that we have to produce representations ourselves. To judge or think is to refer sensible representations to one concept. Concepts may be empirical and pure. There are a priori forms in our understanding Kant calls categories (ways of thinking or judging). The apparent from the types of trial. Call this deduction metaphysical deduction of the categories. According to Kant, there are twelve categories: unity, plurality, totality, reality, negation, limitation, substance and accident, cause and effect, reciprocity, possibility or impossibility, whether or not, and need or contingency. The categories are a priori forms of understanding (shape or structure of knowledge from a material sense), concepts, pure and transcendental conditions (determines the knowledge). According to Kant, the categories or pure concepts are applicable only to the intuitions. When asked how synthetic judgments are possible a priori physics, Kant believes that the rules for the use of the categories are the laws of experience, called principles of understanding. In transcendental idealism, he marks the difference between phenomenon and noumenon (or things in themselves). The object appears and is designed so-called phenomenon, and noumenon or things in themselves is as far as it is something only understood. Noumenon distinguishes two senses: concept (not felt), and as a positive concept (which someone if he had perceived intellectual intuition: God). As we only have sensible intuition, as noumenon is a negative concept.
The distinction between phenomenon and noumenon can understand why Kant calls its doctrine transcendental idealism.