Kant’s Philosophy: A Critical Examination of Reason and Knowledge
Kant’s Turnaround
Kant describes the transformative nature of his philosophy, drawing an analogy with the Copernican revolution. In astronomy, Copernicus’s shift from an Earth-centered to a sun-centered model revolutionized our understanding of celestial motion. Similarly, Kant argues for a revolution in philosophy.
Prior philosophical thought viewed the knowing subject as passive, with the object of knowledge influencing the subject to create a faithful representation of reality. This explains empirical knowledge but not a priori knowledge, which involves knowing something before experiencing it. Kant reverses this relationship, proposing that the knowing subject is active; in the act of knowing, the subject shapes the known reality. Synthetic a priori knowledge is possible if we accept that things conform to our way of knowing. The subject possesses a mental structure that organizes external data. This “Copernican Turn” asserts that knowledge isn’t the subject’s adequacy to the object, but the object’s adequacy to the subject. We know “things” only as they appear under the a priori conditions of knowledge set by the subject.
Reason has three faculties: sensibility, understanding, and reason, each with its priority. In sensibility, we find the pure intuitions of time and space, fundamental to mathematics. Understanding provides categories like cause and substance, crucial for physics. Reason generates ideas of God, the soul, and the world.
Rationalism and Empiricism
Modern philosophy’s central problem is knowledge: its origin, nature, and limits. Rationalism and empiricism offer contrasting perspectives. Both agree that reality exists independently of the knowing subject and that ideas mediate between reality and our minds. However, they differ significantly in their epistemologies.
Rationalism, prominent in 17th-century Europe, emphasizes reason as the primary source of knowledge. It prioritizes reason over sensory knowledge, viewing the senses as potentially deceptive. Reason is autonomous, capable of establishing fundamental truths from which others can be deduced. Rationalists posit innate ideas and believe knowledge is potentially unlimited because reason is infinite. They consider metaphysics a science and employ a deductive, mathematical model of knowledge acquisition, aiming for objective and universal knowledge. Descartes, with his concepts of the thinking self, God, and the world, exemplifies this approach.
Empiricism, prevalent in 17th- and 18th-century England, grounds knowledge in experience. It denies innate ideas, viewing the mind as a blank slate (Locke) upon which experience leaves its mark. Knowledge is limited by experience, making metaphysics impossible as a science. Empiricists favor a method based on observation, induction, and analysis of facts, yielding probable rather than certain knowledge. Hume represents the culmination of this perspective.
Transcendental Illusion
Kant identifies a “transcendental illusion”—reason’s tendency to seek the unconditioned (beyond experience). The Critique of Pure Reason sets limits on this pursuit. Reason’s three faculties—sensibility, understanding, and reason—each contribute a priori elements to knowledge.
In sensibility, we have pure intuitions of space and time. In understanding, we find categories like causality. Reason generates ideas of God, the soul, and the world. Knowledge begins with sensory impressions, organized by sensibility into “phenomena.” Understanding categorizes these to form judgments and laws, while reason unifies them into theories.
Reason’s capacity to connect judgments leads to a tendency to seek ever more general conditions, ultimately the unconditioned—the “thing in itself” or noumenon. This attempt to encompass all experience by reaching the unconditioned generates the ideas of God, the soul, and the world. This is reason’s transcendental illusion.