Kant’s Critique of Pure Reason: Key Concepts
Kant’s Critique of Pure Reason: Key Concepts
This text is a preface to the second edition of Critique of Pure Reason, written by Kant in 1787. It provides a summary of the main thesis of Kant’s transcendental idealism. In this prologue, Kant exposes the fundamental aspects of his critique of the speculative use of reason, whose power and limits he seeks to determine.
Three Questions
For Kant, the question of knowledge, “What can I know?”, is one of the three big questions of philosophy, along with “What should I do?” and “What may I hope for?”. All these questions are summarized in “What is man?”. To which Kant replies: knowledge, action, and hope.
Metaphysics as a Possible Science
To try to answer these questions, Kant uses a critical method by which reason itself is examined to determine its uses and limitations. He examines the theoretical use of reason and determines whether metaphysics is possible as a science. He also explores scientific knowledge. Kant concludes that logic and science progress. Science is possible because there are two conditions: the empirical (from experience) and the a priori or transcendental (universal and necessary, understood in space and time).
Judgments
Once we know what conditions are concerned, Kant investigates how it is possible to investigate, and he turns to judgments. There are two kinds of judgments: analytic and synthetic. Analytic judgments are universal and necessary, while synthetic judgments are particular, a posteriori, and extend and increase knowledge. Kant argues that synthetic a priori judgments are found in mathematics and physics and are those that advance science.
Sensitivity, Understanding, and Reason
This means that while all knowledge begins with experience, not all of it arises from experience. There are also a number of a priori forms that belong to the knowing subject. This interpretation of knowledge synthesizes empiricism and rationalism. Transcendental idealism is the basis of Kant’s Copernican revolution. The author argues that the subject plays a crucial role in knowledge by organizing the data of the senses.
Kant claims that the subject constructs knowledge, concluding that it starts with sensitivity, proceeds through understanding, and culminates in reason. Each part corresponds to a section of the book: sensitivity with aesthetics, understanding with analytics, and reason with dialectics.
Aesthetics
From here, Kant concludes that objects are given through a priori forms of sensibility. He studies scientific judgments a priori, which constitutes transcendental aesthetics.
Analytics
Then there is the transcendental analytic, which says that objects are conceptualized. The work of understanding is to understand itself through pure concepts called categories. The largest of these categories is substance. This allows us to understand nature as a system of phenomena connected by necessary laws. A priori judgments are studied in physics.
Dialectics
Thus, the synthesis of sensitivity and understanding produces knowledge of the phenomena of reality. However, there are noumena, according to Kant, which we cannot know but only think. They are things in themselves and are the limits of our knowledge. We think of things that are beyond the senses. Kant distinguishes three: the world, the soul, and God.
Ethics
This is why he will take care of reason, which tries to find increasingly general judgments through the three ideas that mark the limits of knowledge.
Kant, therefore, responds negatively to the question of metaphysics as a science in the transcendental dialectic. However, these ideas play an important role in ethics, which he identifies not with the knowledge of reason but with the practical use of reason. To try to answer the question, “What should I do?”, Kant addresses the practical use of reason in “Foundations of the Metaphysics of Morals.” He analyzes the supreme principle of morality. First, he criticizes previous ethical systems as heteronomous, material, empirical, a posteriori, and hypothetical. After this, he clarifies the principles of his ethics, which is formal, independent, a priori, universal, and categorical. In this way, Kant considers the moral ideal as something other than happiness; it is a duty, a requirement.
Actions, the Categorical Imperative
For Kant, an action is good if it is done out of good will. Kant distinguishes three types of action: contrary to duty, in accordance with duty, and from duty. Actions from duty are performed out of respect for the categorical imperative. An action in accordance with duty is the hypothetical imperative, i.e., it is subject to obtaining an end.
Maxim
Thus, the requirement to act morally is expressed by following the categorical imperative and universal law, which in turn is linked with the maxim of universality: “Act in such a way that you treat humanity, whether in your own person or in the person of any other, never merely as a means to an end, but always at the same time as an end.” For Kant, only the human being is an end in itself; it has dignity.
Postulates of Reason
Finally, his ethics culminates in the three postulates of practical reason: freedom, the immortality of the soul, and the existence of God.
The categorical imperative involves the freedom of the subject, as only an autonomous person can give themselves a moral law. Reason requires us to aspire to virtue, and this perfection is unattainable in a finite life. Therefore, there must be a supreme author of the physical and moral world to ensure the perfect union between virtue and happiness. Therefore, these three postulates show what man can expect and the true meaning of the ideas of reason.