Kant's Epistemology: Transcendental Idealism

Epistemology in Kant's *Critique of Pure Reason*

In the *Critique of Pure Reason* (CPR), Kant answers the first question raised: What can I know? The question of what we know leads to a more specific question: whether or not a metaphysical science is possible, if one can gain scientific knowledge regarding the world, God, or the soul. In his view, there are two conditions that any intended scientific discourse should satisfy: universality in judgment and the provision of information. This being so, he proposes to operate a sea-change in the epistemological field because, if so far we have assumed that "all our knowledge must be guided by the objects," there is no way of knowing something in them *a priori*. He then expresses the need for objects to conform to our cognitive conditions. If such conditions exist to develop *a priori* metaphysical science, metaphysics will be raised to where it belongs; and if not, we will forget it forever (which has not been done).

Transcendental Aesthetic

In the first part of the CPR, the Transcendental Aesthetic, he discovers that sensibility is the repository of pure forms, space and time, as *a priori* forms that unify the subject of the phenomenon that the world has to offer. Space and time are *a priori* conditions that allow mathematics to be considered a science.

Transcendental Analytic

In the second part of the CPR, the Transcendental Analytic, it is the understanding and the ability to conceptualize and judge the phenomenal world that consists of sensibility. Understanding is the bearer of the categories, which are conceived as pure concepts and, when applied to the realm of constituted experience (the phenomenon), allow us to make judgments. The categories are the possibility that makes physics a science.

Transcendental Dialectic

In the third part of the CPR, the Transcendental Dialectic, Kant critiques theoretical reason, acknowledging two uses. Theoretical reason, in its logical use, unifies the judgments made by the understanding of arguments. However, in its pure use, reason tries to unify these very general ideas into arguments. It is then, when reason engenders metaphysical ideas (God, Soul, and World) and intends, by giving them a constitutive character, to obtain knowledge of the unconditioned, of the thing itself, the noumenon. Kant concludes that such ideas cannot be known; they do not correspond to anything given to us by the empirical world, so they cannot be objects of knowledge. The limit of established knowledge is the experience made possible by the transcendental subject. Metaphysics is thus not a science.

Transcendental Idealism

Kant declares himself a transcendental idealist, that is, understanding that the subject of external reality (the world) has two dimensions: the world as phenomenon (the empirical world) and as noumenon (transcendental world). As a phenomenon, it is knowable to the extent that the subject constitutes an object from transcendental and *a priori* conditions, but such a constitution would be impossible without the matter of the phenomenon. As noumenon, the world is entirely unknown to us.

If sensibility and understanding have undergone a shift, it also takes place in the realm of reason. The shift is, ultimately, the primacy of practical reason over theoretical reason, the abandonment of theoretical speculation in favor of reflection aimed at taking action and not being. The noumenon is no longer an object of knowledge but of achievement, comparable in ethics with the *must-be*. So whatever the truth is, it is no longer an object of knowledge either, but of realization. This implies a new conception of philosophy. Kant's philosophy is no longer the contemplative activity developed by a minority eager for truth and beauty, but becomes an instrument to be used to improve the lives of human beings.