The Ontological Argument is an a priori argument for the existence of God It was first formulated by the medieval philosopher Anselm of Canterbury in the 11th century and is based upon the notion that God is the greatest being that could possibly exist. The argument maintains that if it is possible for God to exist, then God must necessarily exist. This is because, by definition, any being that is greater than any other must include the characteristic of existing, which means that God must exist.
The classic version of the Ontological Argument was first articulated by St. Anselm of Canterbury. He argued that because God is defined as the greatest possible being, such a being must necessarily exist since it could not be greater if it did not exist. Anselm's formulation states that:
“God is the being than which nothing greater can be conceived.”
This means that if something is greater than everything else, then it must necessarily exist.
Five best examples of ontological argument include:
1. James Anderson’s Perfection Argument: Anderson suggests that God’s existence is necessary to make sense of perfections such as beauty, love, justice, and so on. If a realm of perfection exists, then God must exist in order to sustain this realm.
2. Malcolm’s Modal Argument: Malcolm’s argument states that if it is possible for God to exist, then it must be necessary for God to exist. This argument is based upon the notion that if something is possible, then it must be necessary.
3. Charles Hartshorne’s Ontological Argument: Hartshorne suggests that if God’s existence is possible, then it is necessary since nothing could be more perfect than a being that exists necessarily.
4. Alvin Plantinga’s Ontological Argument: Plantinga argues that God’s existence is possible because there is no self-contradiction in the concept of a perfect being. He suggests that if it is possible for a perfect being to exist, then it must be necessary for a perfect being to exist.
5. William Lane Craig’s Ontological Argument: Craig’s argument is similar to Hartshorne’s and Plantinga’s in that he suggests that if God’s existence is possible, then it must be necessary. This is because a being that exists necessarily is greater than a being that only exists contingently.