Comparison of ibn Sînâ's and Juwaynî's conceptions of substance (jawhar)

Since their birth, humankind being have thought about existence in terms of existing things, starting from their own existence. In this regard, logical and metaphysical truths have held significant value in explaining the relationship between God, the universe, and humanity throughout the history of thought. With the aim of understanding existence and its source and subsequently making sense of life, the first philosophers evolved some thought systems about the first causes of observable entities. In this context, the idea of jawhar (the substance), which emerged with the search for an essence and was later systematized by traditions and schools, developed as a result of the effort to provide holistic answers to these areas, including the ontological, epistemological, logical, physical and metaphysical aspects of existence. This issue, which comes from ancient times and has been transferred to Islamic thought through many stages, has provided the Islamic philosophy and Kalam (Islamic theology) traditions with the opportunity to holistically discuss issues related to physics and cosmology in connection with the jawhar (the substance), with the problems it contains and the effort to find answers to these problems. Due to these considerations, I discussed jawhar (the substance), a fundamental issue that appeals to many fields of thought and is considered the essence (unchanging reality) of existence in ontological terms. I have selected the names Ibn Sina (Avicenna) and al-Ghazali because of their significant positions within their respective traditions and their original contributions to thought within these traditions. Consequently, in my study, I discussed the trajectory of jawhar (the substance) up to the names Ibn Sina (Avicenna) and al-Ghazali in the two traditions mentioned and in the two different branches within these traditions, as well as the meanings attributed to jawhar (the essence) by these two names in both physical and metaphysical terms, in addition to their analyses of existence.