In the fourth/eleventh century, the world of Islam saw the emergence of three trends in the intellectual sphere: the Sunni theologians believed that the study of theology was causing more harm to common people than good; others felt that religious knowledge was incompatible with secular knowledge; and ordinary Muslims regarded the study of science as irrelevant to their spiritual life. A genius was needed to bring about an intellectual synthesis of these mutually repellent trends. The world of Islam found such a genius in the person of Imam Abū Hamid al-Ghazzalī (450/1058505/1111), who was one of the greatest Sunni scholars. After carefully considering the works of Muslim philosophers such as Abu 'Alī Sīna (Avicenna) and al-Kindī as well as the works of Greek philosophers translated into Arabic, he came to the conclusion that they were not explaining, but were rather explaining away, Islamic beliefs. In criticizing them, al-Ghazzālī restricted the limits of human reason in apprehending Divine Truth. He strongly believed that Sufism alone could revive the religion through its emphasis upon spirituality.