The Mu'tazilites were sponsored by the Caliph al-Ma'mun, who was the greatest supporter of Greek thought in Islamic history. He is said to have had a dream in which Aristotle appeared to him. He asked the philosopher, "What  is the good?" and Aristotle answered, "It is what is rationally good." And so al-Ma'mun embraced this rational school of theology - the Mu'tazilites - and also sponsored al-Kindi, the first Arab philosopher.