The subject of deliberation leads us to the core of ethics, because it concerns a method of reaching practical decisions, and to understand this method requires an understanding of how value concepts can be recognized and estimated in practical situations, and this understanding in turn must be based on understanding what value concepts are. In this paper I shall compare the theories of deliberation of two rationalists of different traditions. Aristotle in ancient Greece and ʿAbd al-Jabbār in classical Islam. Any historical link of affiliation between them is either very indirect or nonexistent, and the interest of comparing them does not reside in a search for origins. It consists rather in illustrating two ways in which deliberation has been thought of in the past, and how each way arose out of its own intellectual tradition and environment.

The choice of Aristotle for this study hardly needs explanation, since he alone of the Greeks gave a detailed discussion of deliberation, in his systematic yet probing manner. On the side of Islam the Muʿtazilite school represents the rationalist tradition in theology, and among them only the works of ʿAbd al-Jabbār survive in substantial length. A Persian who lived in Iran and Iraq in the tenth and eleventh centuries (c. 935–1025 a.d.), this theologian wrote his many volumes of the Mughnī and other books in Arabic, as was usual at that time.