Kant’s Critical Philosophy: Knowledge, Categories, and Metaphysics

Posted on Dec 5, 2024 in Philosophy and ethics

Kant’s Philosophical System

Kant’s philosophical system, known as critical philosophy and transcendental idealism, was primarily developed in The Critique of Pure Reason. According to Kant, knowledge requires distinguishing two types of conditions:

• Empirical conditions: Derived from experience, dependent on facts, a posteriori, and always unique and contingent.
• Transcendental conditions: Preceding experience, dependent on the subject, a priori, universal, and necessary.

Modern science represents a balanced synthesis between experience and reason. Kant examines the empirical conditions of transcendental experience and reason.

Judgments in Science

Kant’s initial inquiry focuses on substantiating the theoretical use of reason (science) through judgments or scientific propositions. A science is an organized system of trials and proposals, such as mathematical theorems and physical laws. What are the characteristic judgments of science? Logic distinguishes types of trials based on the relationship between subject and predicate:

• Analytical: The predicate concept is included in the subject concept; these are tautologies (analyzing the subject reveals the predicate).
• Synthetic: The predicate concept is not included in the subject concept.
• A posteriori: Truth is directly dependent on experience; these judgments are singular and contingent.
• A priori: Truth does not depend on experience; these judgments are universal and necessary.

Therefore, judgments that advance science are synthetic a priori.

Structure of Critique of Pure Reason

In Critique of Pure Reason, Kant establishes the basis for the theoretical use of reason, i.e., scientific knowledge. Human knowledge involves three main faculties: sensibility, understanding, and reason. The Critique has three parts:

• Transcendental Aesthetic: Deals with the transcendental conditions of sensibility.
• Transcendental Analytic: Addresses the transcendental conditions of understanding.
• Transcendental Dialectic: Concerns the transcendental conditions of reason, exploring its possibilities and limitations.

Transcendental Aesthetic

In the transcendental aesthetic, we distinguish two elements:

• Intuition: The direct representation of a single object.
• Sensation: The content of the representation.

Through sensibility, we experience; there are empirical and transcendental conditions of sensibility.

• Empirical conditions relate to the elements involved in sensation (Kant does not address these, considering them the domain of other sciences).
• Transcendental a priori conditions precede experience and make it possible. These are the transcendent conditions of space and time.

Space and Time

Space and time are not sensations but the forms through which we perceive all sensations. They are how we sense any situation.

• A priori: Space and time are not sensations derived from experience but are preconditions.
• Sensitivity: Distinguishes between external and internal materials; external materials are given in space and time, while internal materials are only given in time.
• Intuition: Space and time are singular; parts of space belong to a single space, and time intervals belong to a single time; we cannot have unique concepts of them. We know space and time as intuitions.
• Pure: We cannot have empirical intuitions of space and time because they are not objects. We know them as pure intuitions; the pure intuition of space is three-dimensional, and the pure intuition of time is a feeling of unlimited regular intervals.

The possibility and validity of a priori judgments in mathematics are based on:

• Pure intuition of space: Three-dimensionality without objects, conceptually developed in geometry (synthetic a priori).
• Pure intuition of time: A regular series of intervals, conceptually developed in arithmetic, leading to the notion of number (synthetic a priori).

Transcendental Analytic

Understanding involves comprehending phenomena through concepts. Concepts combine into judgments and reasoning. There are:

• Empirical conditions of knowledge, formed from objects and their properties through abstraction (Kant is not focused on this).
• Transcendental conditions of knowledge, relating to the a priori use of concepts, preceding experience, and providing the logical structure for the subject. According to Kant, these come from the spontaneity of understanding.

Kant’s transcendental analytic derives pure concepts or categories from the forms of judgment proposed by logic, which has twelve ways to form judgments (possible relationships between subject and predicate). Logic divides these twelve forms according to quantity, quality, relation, and modality.

Categories of Understanding

According to Quantity

• Singular: Subject is an individual concept (This S is P); Category: Totality.
• Particular: Subject is a partial concept (Some S is P); Category: Plurality.
• Universal: Subject is a universal concept (All S are P); Category: Unity.

According to Quality

• Affirmative: Predicate affirms the subject (S is P); Category: Reality.
• Negative: Predicate negates the subject (S is not P); Category: Negation.
• Infinite: Predicate excludes a specific quality (S is not P, implying other possibilities); Category: Limitation.

According to Relation

• Categorical: Unconditional predicate (S has property P); Category: Substance and Accident.
• Hypothetical: Conditional predicate (If S, then P); Category: Causality.
• Disjunctive: Alternative predicates (S is either P or Q or R); Category: Community.

According to Modality

• Problematic: Possible predicate (S may be P); Category: Possibility.
• Assertoric: Actual predicate (S is P); Category: Existence.
• Apodictic: Necessary predicate (Necessarily S is P); Category: Necessity.

Transcendental Dialectic

The transcendental dialectic remains within the limits of experience and the proper use of categories (valid or scientific knowledge). Newton unified celestial and terrestrial mechanics in a single formula. However, reason tends to go beyond experience and the categories, aiming for unconditional speculative synthesis. Kant questions whether metaphysics is a science, i.e., if a priori synthetic judgments are possible in metaphysics. This involves ultimate knowledge not conforming to empirical and transcendental conditions.

Metaphysical syntheses are speculative principles, the most general being:

• The soul: Unconditional synthesis of all inner experience.
• The universe: Unconditional synthesis of all external experience.
• God: Unconditioned synthesis of all internal and external experience.

Kant critiques each of these ideas in the transcendental dialectic:

Critique of Metaphysical Ideas

Rational Psychology

Critiques the metaphysical idea of the soul, identifying fallacies that arise from misusing metaphysical propositions about the soul (transcendental synthesis applied to inner experience out of time, misuse of substance and accident outside experience).

Rational Cosmology

Critiques the metaphysical idea of the universe, presenting contradictions that arise when making metaphysical propositions about the universe (whether it has a beginning in time or limits in space, whether matter is infinitely divisible, whether natural causation is the only kind).

Rational Theology

Critiques the metaphysical idea of God, identifying errors in applying categories to objects outside space and time. For example, applying the category of existence or causality to God is improper, as is using the empirical concept of finality for the ultimate cause of the universe.

Conclusions of the Transcendental Dialectic

1. There are no a priori synthetic judgments in metaphysics; it is not a science but a transcendental illusion.
2. Categories are not applicable beyond experience, i.e., beyond what is given in space and time. We can know phenomena but not things in themselves (noumena).
3. Metaphysics can have other uses: a negative regulative use, separating scientific knowledge from non-scientific, and a positive regulative use, encouraging scientific research to transform metaphysical propositions into scientific ones.
4. Metaphysics may lack validity for theoretical reason but can be valid for practical reason (ethics).