 The three volumes of Philosophy bear the titles Philosophical World Orientation (volume I), The Illumination of Existence (volume II), and Metaphysics (volume III). It was written during the 1920s after Jaspers obtained the full professorship at Heidelberg University. Each volume of this book thus describes a particular way of being: orientation, existence and metaphysical transcendence are the three essential existential modalities of human life. At the same time, each volume also describes a particular way of knowing, which is correlated with a way of being: orientation is cognitively determined by objectively verifiable knowledge or by positive or scientific proof-forms, existence is determined by subjective/existential self-reflection, and transcendence is determined by the symbolic interpretation of metaphysical contents. Together, the three volumes of Philosophy are designed to show how human existence and human knowledge necessarily progress from one level of being and one level of knowledge to another, and how consciousness gradually evolves, through confrontation with its own antinomies, from an immediate and unformed state towards a condition of unity and integral self-experience. The three volumes are consequently bound together by the argument that at the level of immediate objective knowledge—of orientation in the world—human consciousness raises subjective-existential questions about itself and the grounds of its truth which it cannot resolve at this level of consciousness, and it encounters antinomies which call it to reflect existentially upon itself and to elevate it to the level of existence or existentially committed self-reflection. At this higher level of consciousness, then, existence raises metaphysical questions about itself and its origin which it cannot begin to answer without an awareness that existence is, at an originary or authentic level, transcendent, and that its truth is metaphysical.