is a slightly different use of the word autochthonous than the ordinary medical or sociological use as a synonym for indigenous.) Secondary delusions, on the other hand, he defined as those influenced by the person's background, current situation or mental state. Jaspers considered primary delusions to be ultimately "un-understandable", since he believed no coherent reasoning process existed behind their formation. This view has caused some controversy, and the likes of R. D. Laing and Richard Bentall (1999, p. 133–135) have criticised it, stressing that this stance can lead therapists into the complacency of assuming that because they do not understand a patient, the patient is deluded and further investigation on the part of the therapist will have no effect. For instance Huub Engels (2009) argues that schizophrenic disordered speech may be understandable, just as Emil Kraepelin's dream speech is understandable. Contributions to philosophy and theology 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. Transcendence (paired with the term The Encompassing in later works) is, for Jaspers, that which exists beyond the world of time and space. Jaspers's formulation of Transcendence as ultimate non-objectivity (or no-thing-ness) has led many philosophers to argue that ultimately, Jaspers became a monist, though Jaspers himself continually stressed the necessity of recognizing the validity of the concepts both of subjectivity and of objectivity. Although he rejected explicit religious doctrines, including the notion of a personal God, Jaspers influenced contemporary theology through his philosophy of transcendence and the limits of human experience. Mystic Christian traditions influenced Jaspers himself tremendously, particularly those of Meister Eckhart and of Nicholas of Cusa. He also took an active interest in Eastern philosophies, particularly Buddhism, and developed the theory of an Axial Age, a period of