Kant’s Epistemology and Ethics: A Priori Knowledge and Moral Duty
The Problem of Knowledge
Metaphysics, unlike other sciences, has not become a definitive science despite its long history. This raises the question of whether metaphysics is possible as a science. Kant attempts to establish principles for scientific knowledge, which for him is certain knowledge. From this, we can establish the conditions any other knowledge must meet to be considered true. Metaphysics, unlike other sciences, seeks to transcend experience and institutional knowledge, exploring concepts like God, the soul, or the world as a whole through a priori concepts. Therefore, we need to rely on understanding and reason rather than experience.
For Kant, there are two sources of knowledge: sensibility, which supplies knowledge from experience (a posteriori knowledge), and understanding, which provides the means of knowledge (a priori knowledge). The conditions for scientific knowledge (K) are necessity and universality, fulfilled by a priori judgments.
Analysis of Judgments
Kant distinguishes several types of judgments:
- Analytical: The predicate is contained within the subject and does not expand our knowledge; these are a priori.
- Synthetic: The predicate adds something new to the subject, broadening our knowledge. These can be a priori or a posteriori; scientific judgments belong to the former, providing new knowledge whose truth does not depend on experience.
Kant investigates how such judgments are possible by studying the three faculties of Reason: sensibility (“Transcendental Aesthetic”), understanding (“Transcendental Analytic”), and reason (“Transcendental Dialectic”).
Transcendental Aesthetic (Sensibility and Mathematics)
Sensibility is the ability to passively receive representations by being affected by objects. In sensibility, immediate knowledge of an object is called sensitive intuition, and its cause is called a phenomenon. The transcendental conditions (prerequisites) of sensibility are pure intuitions: space and time, which belong to Reason, not reality. The perceiving subject applies these pure intuitions spontaneously, creating the phenomenon that is perceived, not the thing-in-itself (noumenon). This, according to Kant, is the Copernican revolution in knowledge: the object to be known must adapt to the conditions of the subject’s reason, not vice versa. Pure intuitions also enable synthetic a priori judgments in mathematics, as the properties of space and time are applied to all phenomena within them, making them universal and necessary.
Transcendental Analytic (Understanding and Physics)
While sensibility supplies intuitions, understanding provides concepts. Sensible intuitions must be thought through a concept to produce knowledge. Understanding, unlike sensibility, is active; it creates concepts, which are forms that organize various representations under a common idea. The union of sensitive data and conceptual knowledge occurs when…
Concepts can be empirical or pure (categories). The latter are the transcendental conditions of understanding, independent of experience, and are applied directly to the intuitions provided by sensibility. We can identify the categories by determining the forms of judgment, as all acts of understanding can be reduced to judgments. There are twelve categories, each corresponding to a type of judgment. These categories are valid only when applied to intuitions provided by sensibility, providing the transcendental form of knowledge.
Understanding is necessary to apply transcendental forms of understanding (categories), so we cannot know noumena as they are in themselves, but only as phenomena through the transcendental structures of sensibility and understanding. Thus, categories enable synthetic a priori judgments in natural sciences, as with space and time in sensibility, transmitting necessity and universality to objects.
Transcendental Dialectic (Reason and Metaphysics)
For metaphysics to be a science, it must make synthetic a priori judgments, as in mathematics and physics. Kant investigates whether such judgments are possible in metaphysics.
Metaphysics studies realities in the noumenal realm, beyond experience: God, the soul, and the world as a whole. Reason illegitimately applies pure categories to objects beyond experience (the noumenon), leading to contradictions. However, there is a natural tendency in reason to seek the unconditioned (that which is not limited by experience). We conclude that while metaphysics is possible as a natural disposition, it is impossible as a science. To have knowledge, an empirical concept must be subsumed under a category, but we lack empirical content for the objects studied in metaphysics.
The Problem of Moral Ethics
Kant addresses moral issues in the Critique of Practical Reason. He begins by distinguishing between material and formal ethics:
- Material Ethics: The basis of obligation or duty must be universal and necessary, so it cannot be based on anything empirical. Kant criticizes material ethics because they are empirical, their precepts are hypothetical (dependent on a stated purpose), and they maintain a heteronomous morality, where moral law does not arise from reason itself but is determined by something external, preventing free action.
- Formal Ethics: Defended by Kant, formal ethics has a formal character, devoid of empirical content. It does not seek specific purposes or rules; it is determined by reason itself, making it a priori, universal, and necessary. According to Kant, this ethic is based on the idea of duty, which is the a priori form of human reason. Performing an action from duty, out of respect for reason itself, constitutes goodwill. Actions are not moral if they merely comply with duty or are contrary to duty; only actions done out of duty are morally right.
Categorical Imperative: This establishes the form of the maxim of moral action. It is universal, necessary, and determined by a priori reason, ensuring that the will, not being determined by empirical evidence, is free to self-determination. This imperative has several formulations, including: “Always act so that your action could become a universal law” and “Always treat every rational being as an end in themselves and never as a mere means.”
Kant posits three postulates of practical reason: The first, and the only one proven in practice, is freedom, as the requirement to respect duty presupposes freedom. The second, not proven but a requirement of reason, is the immortality of the soul, as the line of duty never ends. The third, also not proven, is the existence of God, as the rational demand for the identification of virtue and happiness requires their existence.