Bleeker was one of the foremost scholars of phenomenology of religion in the twentieth century. For Bleeker, phenomenology of religion is a decidedly non-theological task which does not by design promote religion or religious causes. Phenomenology of religion on Bleeker's view has a descriptive and interpretative task which aims to understand the experience of religion without reducing it to the methods of other disciplines such as psychology, sociology, or anthropology. The most important task of phenomenology for Bleeker is eidetic. That is, phenomenology of religion should not just be concerned with describing or categorising religious experiences but should, on the basis of the former, seek to discover the essence of human religion and its fundamental structures. Following the thought of Gerard van der Leeuw, Bleeker held that there are three key concepts for phenomenology of religion: the epoché, the eidetic vision, and intuitive insight — although he maintained that the epoché and the eidetic vision were related to the original Husserlian concepts only figuratively. The epoché is the scholar's suspension of judgement concerning the truth of religious claims, the eidetic vision is the search for the essence of religion, and intuition is the means by which the scholar recognises religion's essence in its empirical manifestations. Using these methods, Bleeker concluded that "the divine" is the key word of religion: the structure of all religion involves a relation of the human to God or the Holy, which produces specific religious rituals or practices.
