Examination of phenomenology as an epistemological foundation of existentialism

In this paper the epistemic sources of existential philosophies are inspected. To this end, first, we explain briefly the antecedent views regarding the value of human knowledge from ancient Greece to contemporary philosophy and philosophy of the 20th century. During the explanation of this historical survey, the idea of phenomenology/internality as one of the epistemic sources of existential philosophies is observed. In this section, the way in that this reflection transfers from Johann Heinrich Lambert (1728 – 1777) and Immanuel Kant (1724 – 1804) in modern history, to Jean-Paul Charles Aymar Sartre (1905 – 1980) and Friedrich Wilhelm Nietzsche (1844 – 1900) and others in contemporary century and existential philosophy is examined. Then the role of mediocrity of this line of thought, i.e., Arthur Schopenhauer (1788 – 1860) as an intermediary student of Kant and direct teacher of Nietzsche is highlighted. Then the position of phenomenology among its homogeneous fields, such as, epistemology, ethics and logic is descripted and distinguished. In this section it will be observed that phenomenology could not be a tendency opposing its homogeneous fields, for phenomenology means to know phenomena, and therefore in this case it is part of knowledge, not opposite to it. Then lexical and terminological concepts, definition, courses and the subject of phenomenology are investigated. In this part we will deduce that it is impossible to give a firm, fixed and definite definition for phenomenology. At the end the theory of phenomenology as a basis of epistemology of existentialism is examined.