The Lectures upon which this volume is based were delivered before the University of Aberdeen between January 11 and February 1, 1899. They appear in a decidedly more extended form than that in which they were delivered; and they have been subject to some revision. Lecture VII, in particular, has been much lengthened in the final preparation for publication. These differences between the lectures as read and the printed volume have seemed to me necessary, in order to complete my statement of the problems at issue, and of the solution that I offer.<br><br>The plan of the whole course is explained more at length in the opening lecture. Lord Gilford's Will calls upon his lecturers for a serious treatment of some aspect of the problems of Natural Religion. These problems themselves are of the most fundamental sort; and in this first Series I have not seen my way clear to attempting anything less than a philosophical inquiry into first principles. The second Series, especially in its later lectures, will contain the more detailed application of these first principles to problems that directly concern religion.