Chapter III. The Ideal of Pure Reason. Section I. Of the Ideal in General. Section II. Of the Transcendental Ideal (Prototypon Trancendentale). Section III. Of the Arguments employed by Speculative Reason in Proof of the Existence of a Supreme Being. Section IV. Of the Impossibility of an Ontological Proof of the Existence of God. Section V. Of the Impossibility of a Cosmological Proof of the Existence of God. Section VI. Of the Impossibility of a Physico-Theological Proof. Section VII. Critique of all Theology based upon Speculative Principles of Reason. Appendix. Of the Regulative Employment of the Ideas of Pure Reason. II. Transcendental Doctrine of Method Chapter I. The Discipline of Pure Reason. Section I. The Discipline of Pure Reason in the Sphere of Dogmatism. Section II. The Discipline of Pure Reason in Polemics. Section III. The Discipline of Pure Reason in Hypothesis. Section IV. The Discipline of Pure Reason in Relation to Proofs. Chapter II. The Canon of Pure Reason. Section I. Of the Ultimate End of the Pure Use of Reason. Section II. Of the Ideal of the Summum Bonum as a Determining Ground of the Ultimate End of Pure Reason. Section III. Of Opinion, Knowledge, and Belief. Chapter III. The Architectonic of Pure Reason. Chapter IV. The History of Pure Reason. PREFACE TO THE FIRST EDITION 1781 Human reason, in one sphere of its cognition, is called upon to consider questions, which it cannot decline, as they are presented by its own nature, but which it cannot answer, as they transcend every faculty of the mind. It falls into this difficulty without any fault of its own. It begins with principles, which cannot be dispensed with in the field of experience, and the truth and sufficiency of which are, at the same time, insured by experience. With these principles it rises, in obedience to the laws of its own nature, to ever higher and more remote conditions. But it quickly discovers that, in this way, its labours must remain ever incomplete, because new questions never cease to present themselves; and thus it finds itself compelled to have recourse to principles which transcend the region of experience, while they are regarded by common sense without distrust. It thus falls into confusion and contradictions, from which it conjectures the presence of latent errors, which, however, it is unable to discover, because the principles it employs, transcending the limits of experience, cannot be tested by that criterion. The arena of these endless contests is called _Metaphysic_. Time was, when she was the _queen_ of all the sciences; and, if we take the will for the deed, she certainly deserves, so far as regards the high importance of her object-matter, this title of honour. Now, it is the fashion of the time to heap contempt and scorn upon her; and the matron mourns, forlorn and forsaken, like Hecuba: