This book will assist readers of philosophical literature to understand and to appraise a large section of the controversial philosophical thought of our time. The central theme is the conflict between naturalism and idealism. The idealist philosophy is considered in its historical outcome of subjectivism, as developed in the phenomenological movement. The use of phenomenology is discussed as a general philosophy, as well as with respect to representative philosophies of human existence. The naturalistic view of experience as represented by Dewey is contrasted with the subjectivistic treatment of pure experience which is taken to be somehow prior to nature.