=The age of criticism.=[100]--Kant considered himself as contributing to the further advance of the eighteenth century Enlightenment.[101] In view, however, of the contrast between eighteenth and nineteenth century thought, and of the real affiliations and ultimate consequences of Kant’s teaching, it seems truer to regard the Critical philosophy as at once completing and transcending the _Aufklärung_. Kant breaks with many of its most fundamental assumptions. =The Critique of Pure Reason.=[102]--Kant here defines the _Critique_ as directed upon pure reason.[103] Further, it is a criticism of knowledge which is “independent of all experience,” or, as Kant adds “free from all experience.” Such phrases, in this context, really mean _transcendent_. The _Critique_ is here taken as being a Critical investigation of transcendent metaphysics, of its sources, scope, and limits.[104] =Opinion or hypothesis not permissible.=[105]--Cf. below, p. 543 ff. =I know no enquiries, etc.=[106]--The important questions raised by this paragraph are discussed below, p. 235 ff. =Jean Terrasson= (1670-1750).[107]--The quotation is from his work posthumously published (1754), and translated from the French by Frau Gottsched under the title _Philosophie nach ihrem allgemeinen Einflusse auf alle Gegenstände des Geistes und der Sitten_ (1762). Terrasson is also referred to by Kant in his _Anthropologie_, §§ 44 and 77. Terrasson would seem to be the author of the _Traité de l’infini créé_ which has been falsely ascribed to Malebranche. I have translated this latter treatise in the _Philosophical Review_ (July 1905). =Such a system of pure speculative reason.=[108]--The relation in which this system would stand to the _Critique_ is discussed below, pp. 71-2. Speculative does not with Kant mean transcendent, but merely theoretical as opposed to practical. Cf. B 25, A 15 = B 29, A 845 = B 873. =Under the title: Metaphysics of Nature.=[109]--No such work, at least under this title, was ever completed by Kant. In the Kantian terminology “nature” signifies “all that is.” Cf. below, p. 580. PREFACE TO THE SECOND EDITION I shall again give a brief explanatory paraphrase, before proceeding to detailed comment. The main points of the preface of the first edition are repeated. “Metaphysics soars above all teaching of experience, and rests on concepts only. In it reason has to be her own pupil.”[110] But Kant immediately proceeds to a further point. That logic should have attained the secure method of science is due to its limitation to the mere _a priori_ form of knowledge. For metaphysics this is far more difficult, since it “_has to deal not with itself alone, but also with objects_.”[111]