In his prologue to the moral part of the Summa theologiae, Thomas reflects on the meaning of the truth that man is made in the image and likeness of God. In this man is unique among creatures of the sublunary world. All creatures are like their creator to some degree -- as vestiges and shadows, as Bonaventure will say -- but man shares in capacities that give him dominion over his own life. He has an intellect and free will and thus can both know that which is fulfilling of him and responsibly pursue it.