relating to historical events have often been expressed beneath the false and presumptuous cloak of a philosophy of history; rules and warnings have been formulated, empirical no doubt, yet by no means useless to students and critics. It does not seem possible to deny this utility even to the most recent of philosophies of history, known as historical materialism, which has thrown a very vivid light upon many sides of social life formerly neglected or ill understood. [Sidenote: _Æsthetic intrusions into Logic._] The principle of authority, of the _ipse dixit_, is an intrusion by historicity into the domains of science and philosophy which has dominated the schools and substitutes for introspection and philosophical analysis this or that evidence, document, or authoritative statement, with which history certainly cannot dispense. But Logic, the science of thought and of intellectual knowledge, has suffered the most grave and destructive of all disturbances and errors through an imperfect understanding of the æsthetic fact. How could it be otherwise, if logical activity come after and contain in itself æsthetic activity? An inexact Æsthetic must of necessity drag after it an inexact Logic. Whoever opens a logical treatise, from the _Organon_ of Aristotle to the modern works on the subject, must agree that all contain a haphazard mixture of verbal facts and facts of thought, of grammatical forms and of conceptual forms, of Æsthetic and of Logic. Not that attempts have been wanting to escape from verbal expression and to seize thought in its true nature. Aristotelian logic itself did not become mere syllogistic and verbalism without some hesitation and indecision. The problem proper to logic was often touched upon in their disputes by the nominalists, realists and conceptualists of the Middle Ages. With Galileo and with Bacon, the natural sciences gave an honourable place to induction. Vico combated formalist and mathematical logic in favour of inventive methods. Kant called attention to the _a priori_ synthesis. Absolute idealism despised the Aristotelian Logic. The followers of Herbart, though still loyal to Aristotle, emphasized those judgements which they called narrative and which have a character altogether differing from that of other logical judgements. Finally, the linguists insisted upon the irrationality of the word, in relation to the concept. But a conscious, sure and radical movement of reform can find no basis or point of departure, save in the science of Æsthetic. [Sidenote: _Logic in its essence._]