Kant’s Critique: Metaphysics and the Limits of Knowledge
Before 1770, Kant’s critique of metaphysics focused on scientific issues related to physics or mathematics. However, during his critical period, he began to focus on the problem of metaphysics itself: can metaphysics expose something that qualifies as science? This is reflected in the text, where the author explains that metaphysics has not yet found its method and aims to prove itself, a project undertaken during Kant’s critical period. Kant posed a series of questions, including: “What can I know?” This question addresses the limits of our reason, challenging dogmatism and exploring possibilities in contrast to skepticism.
Dogmatism involves a pure analysis of concepts that are empty and insufficient for genuine understanding. Skepticism, exemplified by Hume, deems metaphysics impossible and suggests that physical laws are merely probable, a point Kant rejected. Moving away from dogmatic and skeptical approaches, Kant employed a new method: the transcendental or critical method.
Can Metaphysics Become Science?
Kant starts from the premise that mathematics and physics are established sciences, dating back to Thales and Galileo-Newton, respectively. Metaphysics, however, has not achieved similar success. Kant defined metaphysics as knowledge whose principles should never derive from experience; it should be a priori knowledge or pure reason, concerning non-empirical objects. Kant addresses the problem by suggesting that metaphysics should consist of scientific propositions akin to those in mathematics and physics. These propositions, or judgments, must expand our knowledge and possess necessary and universal validity.
Kant categorized judgments into two types: analytical, where the predicate is already included in the subject (explanatory and does not increase our knowledge), and synthetic, where the predicate is not in the subject (extensive and increases our knowledge). Synthetic judgments can be a priori (independent of experience, necessary, and universal) or a posteriori (based on experience and probable).
Synthetic A Priori Judgments
Kant argues that scientific judgments must be synthetic a priori, contrary to Hume, who claimed that mathematical judgments were analytical and physical judgments were synthetic and thus probable. How is science possible? How are synthetic judgments a priori? Kant refers to mathematics and physics (pure, without empirical evidence). Mathematics, according to Kant, is made of synthetic a priori propositions. The question arises: how can such propositions be constructed a priori, independent of experience?
The answer lies in the a priori intuitions of space (for geometry) and time (for arithmetic). Mathematics builds all theorems from these intuitions, independent of experience, yet applicable to phenomena. Physics, whose object is nature (the set of all phenomena determined by general laws), also uses synthetic propositions a priori. How can the laws of nature be a priori? Kant responds that understanding does not derive the laws of nature but prescribes them. These categories are the laws of nature. Physical laws are imposed on experience with necessity but only have value in the phenomenal world.
The Role of Pure Reason
After examining these two sciences, we return to metaphysics: Can it be a science? The critique of pure reason suggests not, as knowledge of things in themselves (soul, world, and God) is impossible, and we lack intuition of such beings. Sensitive experience is the limit of all possible knowledge. Thus, metaphysics is impossible as a science. What role do ideas of pure reason play if they do not help us understand anything? They negatively mark the limits that cannot be crossed and positively encourage research to never stop, as ideas become ideals.