1920. Contents: Prologue: The Philosopher's Quest; The Idol of Scientific Method in Philosophy; Philosophy of Nature at the Crossroads; On Doubting the Reality of the World of Sense; Saving the Appearance in the Physical World, Note on John Locke's Distinction of Primary and Secondary Qualities; Mechanism and Vitalism: A Study in the Order of Nature; Mechanism and Vitalism: Further Problems, Note on Bergson and The Origin of Life; Theories of Mind, Note on the Theory of Knowledge; The Self in Self-Consciousness; and Epilogue: Religion and Philosophy of Religion.