In the second/eighth century, Sunni Islam saw the emergence of a group called the Mu'tazilites. It was responsible for whetting the appetite of Muslims for speculative investigations. It adopted logic, philosophy, and rationalism to sharpen the tools of dialectical theology to defend Islam against Christianity, Manichaeism, and other forms of alien religious thought. The Mu'tazilites went into excesses in their beliefs, particularly in respect of tawḥīd (Oneness of God) and the creation of the Quran (khalq al-Qur'ān).
The beatific vision (seeing God in the hereafter) was another matter of controversy among them and other early Islamic schools of thought. The Quran says: "Some faces that Day will beam (in brightness and beauty) looking towards their Lord" (LXXV, 22-23). This verse implies that on the Last Day the faces of the loyal servants of God will be radiant with joy by looking at His Countenance. The same truth is emphasized by the hadīth, many of which assert that one of the boundless blessings that the faithful (mu'minūun) will receive in the hereafter is that they will see God Most High and that this will be the source of the greatest bliss and happiness for them. But the Mu'tazilites denied the possibility of beatific vision on the ground that it was not logically possible because only a thing that exists in material form or has color or surface can be seen by the human eye. They argued that since God has neither form nor substance nor is He contained in space and time, the question of seeing Him does not arise. The possibility of seeing God was rejected by the Mu'tazilites on rationalistic grounds, even though such a rejection meant refuting the relevant verse of the Quran.
Although the Mu'tazilites were Sunnis, such views were not accepted by the majority of Sunnis, who believed that since the Prophet has asserted authoritatively the possibility of the beatific vision in his sayings, and that the sahabah too had drawn no other inference from these ahādīth except that in the hereafter the faithful (mu'minūn) will be blessed with an unconcealed view of God, every Muslim must believe in the possibility of such vision.