Kant’s Transcendental Idealism: Bridging Rationalism and Empiricism
Relationship: Hume and Kant
The author discards the first studies of Kant, which were rationalist. Throughout continental Europe, theories of knowledge are rationalism and empiricism. Discarding rationalism remains in effect. Descartes, in 1637, had published his Discourse on Method, in which he defended the unlimited power of human reason. He believed that if certain innate ideas (i.e., made by me) could derive from them all knowledge, human knowledge could be obtained without recourse to experience. His conclusion is that all three substances are reduced to one main, distinct, and irreducible to each other: the infinite substance, or God, creates the other two: thinking substance (me and my dear) and extended substance.
On the other hand, a century later in England, we see the empiricism of David Hume, who defended that most of human knowledge is not empirical but has a rational basis. Thus, notions such as substance, God, soul, or causes are not only rational but are also empirical, because I do not have strong, live impressions of them. Therefore, they are just words we use to understand, names without any real referent. For Hume, I can only know what my senses or my external experience tell me.
Kant realizes that Hume is right: experience is the foundation of all knowledge. However, he also agrees to discard reason, which is active in knowing; it always contributes some knowledge, if not all. With respect to the philosophical problem, which coincides with the principal problem considered by modern philosophers (the problem of knowledge), Kant does not accept Hume’s critique of metaphysics. Although Hume’s reading forced Kant to abandon his first dogmatism, he did not accept Hume’s metaphysical skepticism.
Kant’s Critique of Hume
Kant accuses Hume of being too short-sighted, staying in his critical examination of metaphysics as he only analyzed the comings of cause and substance. Analyzing the idea of substance, Kant said: “I cannot perceive and take strong and vivid impressions because it is just another of the conditions of the subject to know the objects and to judge about it.” Indeed, what my sensibility shows me is a huge amount of data, sensations, which will give me the same space and time (impressions, as Hume would say). For example: (white, hard, porcelain, heavy, hole). My understanding regroups all of this into a kind of support and says that it is a vase, that it is a substance, which is a category of my knowledge.
Metaphysics seeks to know noumena. According to Kant, it does not meet the conditions that enable knowledge. Although metaphysics is a form of knowledge, it is not a science, nor can the soul and God be known. Empiricists are right in that there is no proper knowledge, but they do not have to say that it is unusable, that we cannot throw it into the fire. Kant thinks we can get to the noumenon via a different path: knowledge.
Kant on Causality
Kant believes that we will never have a strong and live impression of causality because it is not an object. On the contrary, it is what understanding brings to relate two events that occur together in space and time. I call the first cause and the second effect. Causality is, therefore, one of the conditions, subjective and necessary, for the human being to relate to events and, therefore, know and make laws about them.
Kant accuses Hume of having gone too far or having equivocated the way: for Hume, the cause-effect relationship is a simple psychological habit, and therefore the necessity of such a connection is reduced to a subjective, not objective, necessity. Thus, for Hume, not only is metaphysics impossible, but even physical laws are likely to become law (not necessary). This radical skepticism is not acceptable to Kant.
Kant’s Middle Way
He does not accept rationalist dogmatism, as he discards it, nor does he accept the skepticism in Hume’s empiricism, which leads to reducing everything to a phenomenon. Kant sought a middle way. He takes the critical method, using legal terms, and examines that criticism as a court warrant that claims of pure reason. Therefore, it can be decided on the possibility or impossibility of metaphysics, its source, its extension, and its limits.
Transcendental Idealism
Kant replaced the realistic vision with an idealistic one. For philosophical realism, the real is given, and we can grasp it by experience (empiricism) or by reason (rationalism). For idealism, reality is a result of human construction. If Descartes is the father of rationalism and Hume the most prominent empiricist, Kant is the creator of the transcendental method. On this basic intuition turns the Kantian philosophical method. Thought had turned on nature. From Kant, it will turn on the subject rationally. This represents, as Kant himself said, a Copernican revolution in philosophy.