Critique of Practical Reason

The Critique of Practical Reason is the second of Immanuel Kant's three critiques, published in 1788. It follows on from Kant's first critique, the Critique of Pure Reason and deals with his moral philosophy. While Kant had already published one significant work in moral philosophy, the Groundwork of the Metaphysic of Morals (1785), the Critique of Practical Reason was intended to both cover a wider scope and place his ethical views within the larger framework of his system of critical philosophy. The second Critique exercised a decisive influence over the subsequent development of the field of ethics and moral philosophy, beginning with Johann Gottlieb Fichte's Doctrine of Science and becoming, during the 20th century, the principal reference point for deontological moral philosophy. Preface and introduction Kant sketches out here what is to follow. Most of these two chapters focus on comparing the situation of theoretical and of practical reason and therefore discusses how the Critique of Practical Reason compares to the Critique of Pure Reason. The first Critique, "of Pure Reason", was a criticism of the pretensions of those who use pure theoretical reason, who claim to attain metaphysical truths beyond the ken of applied reasoning. The conclusion was that pure theoretical reason must be restrained, because it produces confused arguments when applied outside of its appropriate sphere. However, the Critique of Practical Reason is not a critique of pure practical reason, but rather a defense of it as being capable of grounding behavior superior to that grounded by desire-based practical reasoning. It is actually a critique, then, of the pretensions of applied practical reason.