International Society for Science & Religion - Library Project

Prolegomena to any Future Metaphysics that Will Be Able to Come Forward as Science with Kant's letter to Marcus Herz, February 1772. Translated by P. Carus and James W. Ellington

by Immanuel Kant

Introductory Essay by Dirk Evers

The epistemology of the German philosopher Immanuel Kant is based on his famous Critique of Pure Reason which deeply influenced not only the course of philosophy, but also the reflection of science on its methods, especially in Germany. In his Critique, Kant laid the ground for metaphysics as science by reflecting on the difference between appearances and things in themselves as well as on the limits of theoretical reason with regard to experience. One of Kant’s intention in this work is the rejection of Humean empiricism, according to which the laws of science are derived from purely contingent events in space and time, through custom, and according to considerations of simplicity, etc.

The argument of the Critique of Pure Reason being quite technical and difficult, Kant was disappointed by its poor reception and tried to remedy this by writing, two years later, the Prolegomena to any Future Metaphysics as an introduction of sorts to his earlier work. As such an introduction, the Prolegomena are still widely read. In them, Kant develops his project of metaphysics as science in three parts.

Presupposing the difference between analytical and synthetical propositions a priori, he shows that pure mathematics as well as pure natural science (which is not just “study of nature”) are only possible if space and time are given as the forms of external sensual experience as well as certain a priori categories which make ordered, coherent experience possible. Only then real knowledge of the natural world, including the universal laws of nature, can be justified.

In the third part Kant argues that metaphysics, i.e. the attempt to go beyond the realm of spatio-temporal experience, is an irrefutable quest of reason with regard to the transcendent ideas of freedom, the soul, and the divine being. But, by asking for the transcendent, theoretical reason gets entangled in a dialectic of contradictions. Therefore, transcendental ideas must be regarded as scientifically inaccessible but, at the same time, as reasonable postulates for practical human reason. The final appendix of the Prolegomena contains a detailed refutation of an unfavorable review of the Critique of Pure Reason.