Economic historian Sabri F. Ülgener is a social scientist who interested in different disciplines and educated in different sciences. Ülgener focused on, in Turkey, inability to achieve capitalist development, particularly the extent and scope of the relationship between economic decline and mentality. Using literary and religious sources related to the period, Ülgener examines the ethics of economy, economic mentality and dissolution concepts. He argues that, despite the progress of the Western world, the material and moral reasons of the economic decline experienced by the Eastern world should be taken into account together. According to Ülgener, the decline of the Ottoman Empire was more about turning into a medieval morality in terms of intellectual, artistic and educational rather than political and military. Medieval morality imposes a closed lifestyleEconomic decline is closely related to morality and mentalityIn this study, in the center of Ülgener's work titled “(İktisadî Çözülmenin Ahlâk ve Zihniyet Dünyası) The Moral and Mental World of Economic Dissolution”, economic decline, the mentality roots of the failure of the entrepreneurial culture and their consequences were tried to be emphasized.