This article is an effort to survey standpoint of Existentialism about one of the issues in classic philosophy on ontology. This issue is important especially because followers of this school, instead of managing universal concepts, try to identify the real existence of human that involve with different problems during the life. Therefore revising of their viewpoints seems worthy.Avoiding from confuse speaking, in this article we have chosen Karl Jaspers (1883-1969) who is, after Soren Kierkegaard (1813-1855), the most important person among the divine Existentialists. Between numerous issues in philosophy of Jaspers, first a report is given about Jaspers`s ontological and anthropological views (including world, transcendence, empirical being, Dasein, consciousness at large, spirit, existenz, and some of the main characters of special human existence) and then, it is considered Jaspers`s views about causality, that is an important subject of ontology in classic philosophy on one hand, and on the other hand it gets more importance because of the idea of necessary connection between "efficient cause" and "effect" and its challenge with human`s free will.Jaspers has some words in acceptance and denial of causality, so there are some solutions at the end of the article to eliminate this inconsistence and to make coherence between his words, such as this solution: we can consider standpoint of Jaspers like the Muslim philosophers, and say he believe in linear chain of causality.
Jaspers, Karl (1955), Reason and Existenz, translated by William Earle, New York, Noonday Press. Jaspers, Karl (1959), Truth and symbol: from Von der Wahrheit, Twayne Publishers.
Jaspers, Karl (1962), The Great Philosophers, vol 1, Harcourt, Brace & World.
Jaspers, Karl, (1973-A) Philosophie I (Philosophische Weltorientierung) Springer DE.
Jaspers, Karl, (1973-B) Philosophie II Existenzerhellung, Springer DE.
Jaspers, Karl, (1987), Existenzphilosophie - Vol 108 of Zur Kritik der bürgerlichen Ideologie. Author, Hans-Martin Gerlach. Publisher, Acad.Verlag.
Haspers, John (1988), AnIntroduction to philosophical Analysis, Routledge.
Wallraff Charles F (1970), Karl Jaspers, An Introduction to His philosophy, Princeton University Press.