The dominance of science as well as its status are indisputable in today’s culture. Today, while rationality has come to be identified with science, natural science is considered to be the best instance of rational thought. Halil Rahman Açar expounds the problem of rationality that has always been a core philosophical issue as it is today. Açar presents to us, rationality, not only as an issue of science or philosophy, but also of ethics, religion, psychology, sociology and anthropology. He critiques the identification of scientific knowledge with rationality.Rationality, as Açar develops, should be considered as an alternative system of interpreting knowledge which seeks a synthesis between extreme pools. This study, while examining the very notion of rationality, leading to truth and science, questions the assumed paradigm of human rationality in reference to its nature and the concepts of objectivity, truth and progress in science.