Nizari Ismaili theology is the pre-eminent negative or apophatic theology of Islam because it affirms the absolute Oneness of God ("tawhid") through negating all names, descriptions, conceptions, and limitations from God. The Ismaili theology of tawhid goes back to the teachings of the early Shi‘a Imams, especially Imam Ali ibn Abi Talib (d. 661), Imam Muhammad al-Baqir (d. 743), and Imam Ja‘far al-Sadiq (d. 765). Additionally, a number of eminent Ismaili Muslim philosophers—Abu Ya‘qub al-Sjistani (d. 971), Ja‘far ibn Mansur al-Yaman (d. 960), Hamid al-Din al-Kirmani (d. 1021), al-Mu’ayyad al-Din Shirazi (d. 1077), Nasir-i Khusraw (d. 1088), Abd al-Karim al-Shahrastani (d. 1153), Nasir al-Din al-Tusi (d. 1273)—consolidated and refined the Ismaili theology of tawhid using the strongest philosophical arguments of their time. Even in the present age, Imam Shah Karim al-Husayni Aga Khan IV, the present and 49th hereditary Imam of the Shi‘a Ismaili Muslims, continues to stress the absolute and utter transcendence of God. At the 1975 All-Ismailia Paris Conference, the Ismaili Imam endorsed and approved the following resolution concerning the contemporary Ismaili position on the concept of God: