Most commentators associate Jaspers with the philosophy of existentialism, in part because he draws largely upon the existentialist roots of Nietzsche and Kierkegaard, and in part because the theme of individual freedom permeates his work. In "Philosophy" (3 vols, 1932), Jaspers gave his view of the history of philosophy and introduced his major themes. Beginning with modern science and empiricism, Jaspers points out that as we question reality, we confront borders that an empirical (or scientific) method simply cannot transcend. At this point, the individual faces a choice: sink into despair and resignation, or take a leap of faith toward what Jaspers calls "Transcendence". In making this leap, individuals confront their own limitless freedom, which Jaspers calls "Existenz", and can finally experience authentic existence.