Kant’s Philosophy: Knowledge, Reason, and Morality
Kant’s Philosophy: A Critique of Reason
The Problem of Knowledge
Immanuel Kant’s work centers on critiquing reason, exploring its capabilities and limits. He sought to answer fundamental questions: What can I know? What should I do? What can I hope for? These converge into the ultimate question: What is man?
In his Critique of Pure Reason, Kant addresses the preconditions and limits of knowledge. He asserts that true knowledge comes from scientific inquiry. To determine which judgments are scientific, he distinguishes several types:
Types of Judgments
By Form:
- Analytical Judgments: The predicate is contained within the subject, expanding our knowledge without adding new information.
- Synthetic Judgments: The predicate adds new information to the subject.
By Content:
- A Priori Judgments: Universally and necessarily true, independent of experience.
- A Posteriori Judgments: Derived from experience; specific and contingent.
Kant argues that the fundamental laws of science are synthetic a priori judgments. They expand our knowledge and are universally true, independent of experience.
The Faculties of Human Knowledge
To understand synthetic a priori judgments, Kant analyzes the three faculties of human knowledge: sensibility, understanding, and reason.
1. Sensibility (Transcendental Aesthetic)
Sensibility is the capacity to receive impressions from the external world. These impressions, or intuitions, are structured by two pure forms of sensibility: space and time. These a priori forms allow us to perceive everything within spatial and temporal dimensions. Space and time make synthetic a priori judgments in mathematics possible.
2. Understanding (Transcendental Analytic)
Understanding is the faculty of concepts and judgments, essential for comprehension. Kant distinguishes between empirical concepts (based on sensory intuitions) and pure concepts or categories (a priori rules that organize sensations). The categories correspond to types of judgments. The laws of physics are synthetic a priori judgments, resulting from applying categories to experience.
Kant introduces the distinction between the phenomenon (the object as it appears to us) and the noumenon (the thing-in-itself, beyond our experience). He argues that we can only know phenomena, not noumena. This distinction forms the basis of his transcendental idealism: valid knowledge arises from combining experience with a priori rules.
3. Reason (Transcendental Dialectic)
Reason establishes relationships between judgments, forming arguments. It drives us to seek ever-more-general explanations. Metaphysics deals with ideas beyond our experience: the world, the soul, and God. Kant argues that metaphysics cannot be a valid science, as applying categories beyond experience leads to errors. However, these ideas of pure reason, though unknowable, serve as regulative ideas, guiding our knowledge.
Practical Reason and Morality (Critique of Practical Reason)
In the Critique of Practical Reason, Kant explores the practical use of reason, addressing the question: What should I do? Practical reason concerns a priori principles of action, focusing on how we ought to behave.
Kant initiated ethical formalism, criticizing material ethics for its heteronomous, a posteriori, and hypothetical rules. He sought an autonomous, a priori, and universal principle for conduct, which he found in the moral law. From this law arises the categorical imperative, with absolute, unconditional, universal, and necessary terms. One formulation is: “Act only according to that maxim whereby you can at the same time will that it should become a universal law.” Kantian ethics is an ethic of duty, autonomous and formal, where the will imposes its own law.
Kant acknowledges three postulates necessary for moral action, though not theoretically demonstrable: freedom of the will, immortality of the soul, and the existence of God. Thus, practical reason recovers what theoretical reason could not attain, admitting them as regulative ideas.