Kant's Philosophy: Reason, Morality, and Metaphysics

Kant's Philosophy

Theoretical Reason

Kant supports the French Revolution and trusts in reason. Pure reason has two uses: theoretical and practical. Theoretically, Kant questions if metaphysics is a science, like math and physics, which derive from pure reason. He uses a Copernican shift, imposing laws on objects for scientific progress. This explains a priori knowledge (universal and necessary) in science. Scientific knowledge should have material and formal elements, expressed in judgments. Scientific judgment must facilitate progress and be a priori.

Transcendental Aesthetics

Perceptual knowledge from external reality is arranged in space and time by a priori forms of sensibility. This perception is necessary for the next step: knowing.

Transcendental Logic

Intellectual knowledge involves representations of disordered phenomena. A priori forms order these phenomena, which are outside our perception. This leads to new empirical knowledge, marking the limits of knowledge.

Transcendental Dialectic

Only a priori forms (ideas of pure soul, world, and God) exist, not phenomena. Thus, there's no scientific knowledge or judgment in metaphysics. We can only think, but reason ambitiously seeks the unconditioned: 1. the whole world (phenomena), 2. the soul (a priori subject), 3. God (world soul).

Conclusion: Metaphysical objects, from a theoretical perspective, are problematic and cannot be known, only thought.

Practical Reason

The "fact of practical reason" and the existence of morality, conscience, or laws are indisputable. Practical standards can be subjective or objective. Objective principles include:

Hypothetical Imperative

Its universality depends on a condition. Typical of material ethics, it states, "If you want X, do Y."

Categorical Imperative

Its universality is unconditional and without exception: "Duty for duty's sake." Morality seeks a universal and necessary moral law. Three of Kant's five formulations of the categorical imperative are: 1. Our actions should be universalizable. 2. Our actions should align with universal laws of nature. 3. Do not use others or yourself merely as means, but as ends in themselves (as persons, not things). Do not enslave anyone.

Morality requires freedom, which is the ratio essendi of morality and the ratio cognoscendi of freedom.

The Soul's Immortality

We know the body dies, suggesting another world where justice exists. Happiness is not always received here, implying immortality and justice in another world. Nothing here satisfies our desire for perfection. Only a perfect being (God) can satisfy this desire, granting perfection and justice in the afterlife.

Conclusion: Kant discards dogmatic use and Hume's skepticism. Humans can desire and believe in these three metaphysical objects. As long as humans exist, metaphysics exists.