  Leibniz presented a number of arguments for the existence of God, which represent great contributions to philosophical theology and which will be discussed below. But one of the most basic principles of his system is that God always acts for the best. While this is generally treated as an axiom, the opening of the Discourse on Metaphysics does present something of an argument for it: “God is an absolutely perfect being”; “power and knowledge are perfections, and, insofar as they belong to God, they do not have limits”; “Whence it follows that God, possessing supreme and infinite wisdom, acts in the most perfect manner, not only metaphysically, but also morally speaking…” (AG 35) This might not appear a surprising claim from a theist, but it is not obvious that God must always act for the best or even create the best world. (See Adams 1972) And Leibniz sometimes implicitly, sometimes explicitly, appeals to this principle in his metaphysics, most notably when he is also employing the Principle of Sufficient Reason.  Indeed, when it comes to the creation of the world, the “sufficient reason” for God's choice of this world is that this world is the “best” of all possible worlds; in other words, in this case the Principle of Sufficient Reason is essentially the Principle of the Best. 