Modern Philosophy: Kant
Kant's critical philosophy is the hinge of the Aragón PAU programme. The exam tests whether you can explain the Copernican turn, the synthetic a priori, the limits of knowledge and the moral law as one connected position rather than three separate topics.
The Copernican turn
Instead of asking how our cognition conforms to objects, Kant asks how objects must conform to the conditions of our cognition. Space and time are forms of intuition (sensibility); the categories - causality, substance, unity and the rest - are pure concepts of the understanding. Experience is possible only because intuition and concepts cooperate. What we know are appearances (phenomena); things in themselves (noumena) can be thought but not known.
Synthetic a priori and its limits
A judgement is synthetic when the predicate adds content and a priori when it holds with necessity and universality. "7+5=12" is synthetic a priori: it is not contained in the concepts, yet it is necessary, because it rests on the pure intuition of time. Causality is likewise a condition of possible experience. Transcendental dialectic shows that soul, world and God are ideas of reason that outrun possible experience; the antinomies expose contradictions when they are treated as objects of knowledge.
The moral law
The categorical imperative commands unconditionally: act only on a maxim you could will as universal law. The humanity formula forbids treating persons merely as means. Morality rests on autonomy - the will legislating for itself - and the good will is good without qualification. Duty, not inclination, determines moral worth; freedom, immortality and God are postulates of practical reason.
Worked example
Asked why "7+5=12" is not analytic, argue: the concept "12" is not contained in "7", "5" or "+"; the result is not derived by analysing concepts but by constructing the sum in pure intuition. Yet the judgement is universal and necessary, so it is not empirical either. Hence it is synthetic a priori - the model of how metaphysics can have secure principles.
Traps
- Calling Kant a subjective idealist in Berkeley's sense: he affirms empirical realism.
- Saying noumena are nothing; they are thinkable limits on knowledge.
- Identifying the categorical imperative with the golden rule, or with hypothetical imperatives.
- Forgetting that Kant grounds morality in reason, not in feeling or consequences.