In Christology, Logos ( logos, that is, "word", "discourse" or "reason" i.e., rationality or reasoning) is a name or title of Jesus Christ, seen as the pre-existent Second Person of a Trinitarian God. It has been important in endeavoring to establish the doctrine of the divinity and morality of Jesus Christ and his position as God the Son in the Trinity by Trinitarian theologians as set forth in the Chalcedonian Creed.