in shaping our cosmological scheme. Its business is to render explicit, and — so far as may be — efficient, a process which otherwise is unconsciously performed without rational tests.
Bearing this in mind, I have avoided the introduction of a variety of abstruse detail respecting scientific advance. What is wanted, and what I have striven after, is a sympathetic study of main ideas as seen from the inside. If my view of the function of philosophy is correct, it is the most effective of all the intellectual pursuits. It builds cathedrals before the workmen have moved a stone, and it destroys them before the elements have worn down their arches. It is the architect of the buildings of the spirit, and it is also their solvent: — and the spiritual precedes the material. Philosophy works slowly. Thoughts lie dormant for ages; and then, almost suddenly as it were, mankind finds that they have embodied themselves in institutions.
This book in the main consists of a set of eight Lowell Lectures delivered in the February of 1925. These lectures with some slight expansion, and the subdivision of one lecture into Chapters VII and VIII, are here printed as delivered. But some additional matter has been added, so as to complete the thought of the book on a scale which could not be included within that lecture course. Of this new matter, the second chapter — ‘Mathematics as an Element in the History of Thought’ — was delivered as a lecture before the Mathematical Society of Brown University, Providence, R. I.; and the twelfth chapter — ‘Religion and Science’ — formed an address delivered in the Phillips Brooks House at Harvard, and
