In our study, the discussions of religiousness that occurred in the society in the last period of the Ottoman Empire will be discussed in the context of the studies published in Islamist journals at that time. First of all, the emergence of the concept will be analyzed, and then the opinions expressed in the studies mentioned will be included. The perspective of Mustafa Asım Efendi who grew up in the Ottoman society, which entered the modernization process after the Tanzimat period, on the concepts of religiousness and irreligiousness in the world in the early 20th century will be evaluated through two comprehensive articles on the subject. The perception of religiousness and irreligiousness of the Ottoman intelligentsia, which was busy with wars, defeats and depressions, will be reflected through a distinguished intellectual example, in the world where positive science declared its dominance in every field and there is no place for belief in the face of science. First of all, brief information about Mustafa Asım Efendi's life and scientific personality will be given. What Mustafa Asım Efendi means by religiousness will be mentioned, how he looks at the concepts of irreligiousness, ignorance and blasphemy, and a determination study will be made on the religious and socio-cultural background of his view on these concepts. In addition, a connection will be made between current problems such as religiousness, deism and atheism and the place in the mind of an Ottoman intellectual in the conflict between religion and science in the modern world at the end of the 19th and the beginning of the 20th century