This dissertation argues that the epistemology of Al-$\underline{\rm Gh}$azzaliyy (450 A.H./1058 C.E.-505 A.H./1111 C.E.) evolved through different stages in his life. He began his life as a conformist, that is, accepting knowledge on the authority of parents and teachers; but soon he broke with conformism and began his quest for truth which led him to experience the most original and dramatic case of skepticism in the history of thought. The only way out of his crisis was divine illumination. After he regained his trust in logical necessities, he studied all the existing schools of thought including philosophy and dialectical theology ('ilm al-kalam); his search culminated in his acceptance of Sufism (i.e., Islamic mysticism) as the only path that leads to what he described as peremptory knowledge ('ilm yaqin).
The introduction includes the state of research on Al-$\underline{\rm Gh}$azzaliyy's epistemology and a statement of the problem.
Chapter one presents a sketch of Al-$\underline{\rm Gh}$azzaliyy's life as an aid to understanding the complexities and the controversies that surround this great Muslim thinker.
Chapter two deals with Al-$\underline{\rm Gh}$azzaliyy's writings as a student and how these writings could be related to his epistemological development.
Chapter three deals with Al-$\underline{\rm Gh}$azzaliyy's writings during the first period of public teaching (478 A.H./1085 C.E.-488 A.H./1095 C.E.) in which he encountered all existing schools of thought in his quest for true knowledge.
Chapter four analyzes the works Al-$\underline{\rm Gh}$azzaliyy wrote in seclusion as a Sufi (488 A.H./1095 C.E.-499 A.H./1106 C.E.).
Chapter five examines Al-$\underline{\rm Gh}$azzaliyy's writings during the second period of public teaching at the Nizamiyyah of Nishapur which lasted for about four years.
Chapter six discusses the last stage in Al-$\underline{\rm Gh}$azzaliyy's life (505 A.H./1111 C.E.). This chapter questions the claim that he abandoned Sufism for the method of the traditionalists.
The conclusion recapitulates the major themes in Al-$\underline{\rm Gh}$azzaliyy's epistemological development.
