The main issue of this article is to examine the religious studies aspects of the anti-realist viewpoint of Don Cupitt- an English theologian - from the entry of examining his viewpoint about God, the religion of mysticism, as well as the analytical findings of the philosophical roots of anti-realism and their criticism. Cupitt believes that realism belongs to the world before the era of historical criticism and anti-realism belongs to the critical era after modernity. From Cupitt's point of view, God, religion and the world do not exist as a reality independent of mind and language, and human knowledge of the world is also done through theories. The present study, while carefully examining the various aspects of Don Cupitt's anti-realism, analyzes its philosophical foundations with an emphasis on the pioneers of modern thought and new philosophical foundations in three existential, epistemological and theological fields, and through the analysis of the philosophical foundations of anti-realism, to the criticism of anti-faith Realist Don Cupitt has discussed; A view that may be effective in understanding the roots of skepticism in the modern era and analyze from a new perspective the realistic search inherent in today's human skepticism.