2014 Reprint of 1918 Edition. Full facsimile of the original edition, not reproduced with Optical Recognition Software. The title-essay of this collection suggests Russell's lifelong preoccupation, the disentanglement, with ever-increasing precision, of what is subjective or intellectually cloudy from what is objective or capable of logical demonstration. The first five essays he calls "entirely popular": they include two on the revolutionary changes in mathematics in the previous hundred years, and the one on the value of science in human culture. The last five, 'somewhat more technical, ' are concerned with particular problems of philosophy: the ultimate nature of matter, the connection between sense data and physics, the problem of causality an different ways of knowing. In these one can see the Russell method in operation, intellectual analysis dissecting the problem to its bare bone. Essays Include: Mysticism and logic.-- The place of science in liberal education.--A free man's worship.--The study of mathematics.--mathematics and the metaphysicians.--The ultimate constituents of matter.--The relation of sense-data to physics.--On the notion of cause.--Knowledge by acquintance and knowledge by description