Produced by Barbara Tozier, Bill Tozier, Michael Zeug, Lisa Reigel, and the Online Distributed Proofreading Team at http://www.pgdp.net Transcriber's Note: Greek words may not display properly--in that case, try another version. Transliterations of Greek words can be found in the ascii and html files. Words italicized in the original are surrounded by _underscores_. Characters superscripted in the original are inclosed in {} brackets. ESSAYS TOWARDS A THEORY OF KNOWLEDGE _Rosalind:_ I pray you, what is't o'clock? _Orlando:_ You should ask me, what time o' day; there's no clock in the forest. _As You Like It, Act III. Sc. 2._ ESSAYS TOWARDS A THEORY OF KNOWLEDGE BY ALEXANDER PHILIP F.R.S.E [Illustration] LONDON GEORGE ROUTLEDGE & SONS LIMITED NEW YORK: E. P. DUTTON & CO. 1915 ἡ γὰρ ἀχρώματός τε καὶ ἀσχημάτιστος καὶ ἀναφὴς οὐσία ὄντως οὖσα ψυχῆς κυβερνήτη μονῳ θεατῂ νῶ, ρεπὶ ἧν τὸ τῆς ἀληθοῦς ἐπιστήμης γένος, τοῦτον ἔχει τὸν τόπον.--PHÆDRUS. PREFACE Two years ago, in the preface to another essay, the present writer ventured to affirm that "Civilisation moves rather towards a chaos than towards a cosmos." But he could not foretell that the _descensus Averni_ would be so alarmingly rapid. When we find Science, which has done so much and promised so much for the happiness of mankind, devoting so large a proportion of its resources to the destruction of human life, we are prone to ask despairingly--Is this the end? If not; how are we to discover and assure for stricken Humanity the vision and the possession of a Better Land? Not certainly by the ostentatious building of peace-palaces nor even by the actual accomplishment of successful war. Only by the discovery of true first principles of Thought and Action can Humanity be redeemed. Undeterred by the confused tumult of to-day we must still seek a true understanding of what knowledge is--what are its powers and what also are its limitations. Nor may we forget that other principle of life--with which it is so quaintly contrasted in Lord Bacon's translation of the Pauline aphorism--_Knowledge bloweth up, Charity buildeth up._ _January 1915._ CONTENTS PAGE I TIME AND PERIODICITY 11 II THE ORIGIN OF PHYSICAL CONCEPTS 17 III THE TWO TYPICAL THEORIES OF KNOWLEDGE 36 IV THE DOCTRINE OF ENERGY 81 ESSAYS TOWARDS A THEORY OF KNOWLEDGE I TIME AND PERIODICITY