Al-Mu'tazila is an Islamic theological school that emerged in the 8th century. It is known for its emphasis on reason and rationality in understanding faith. The Mu'tazilites believed that human reason could discern moral truths and that individuals have free will, which allows them to choose between good and evil. The Mu'tazila also advocated for the unity and justice of God, arguing that God cannot act unjustly. They rejected anthropomorphism, insisting that God is beyond human attributes. Their ideas significantly influenced Islamic philosophy and theology, although their prominence declined by the 10th century due to opposition from other theological schools.