- argument, ontological
- The ontological argument, classically formulated by Anselm of Canterbury and later by Descartes, has been a bone of philosophical contention for nearly a millennium. One formulation of the argument, derived from Anselm, goes like this:1. The concept of God is, by definition, the concept of a being than which nothing greater can be conceived.2. God certainly exists in the mind: even atheists have this concept of God.3. It is greater to exist in reality than in the mind alone.4. Suppose, for a reductio ad absurdum, that God exists in the mind alone.5. Then there would be a concept of a greater being, namely, a concept of a being just like God but also existent in reality (by (3)).6. But there cannot be a concept of a greater being than God (by (1)).7. Therefore, our supposition in (4) was false.8. Therefore, God exists in reality as well as in the mind.Doubt has been cast on this argument at almost every turn: many have complained that the concept of God here employed is the concept of the 'God of the philosophers', but certainly not the concept of the 'God of Abraham, of Isaac and of Jacob'; others have complained that, although atheists have a concept of God, there is no sense in which God 'exists in the mind'; Kant famously complained that one could not compare objects in respect of existence; and still others have tried to find a logical flaw in the argument's structure. Different versions of the argument have been propounded to try to circumvent these objections. Plantinga has devised a modal version of the argument that moves, using the system of modal logic S5, from the premise that it is possible that a necessary being exist, to the conclusion that it is necessary that a necessary being exist. Although Plantinga's argument is valid within his system, this has not stopped the debate; many object that we have no good reason to think it possible that a necessary being exist.See Anselm of Canterbury; Descartes, René; God, arguments for the existence of; Kant, Immanuel; Plantinga, AlvinFurther reading: Barnes, Jonathan 1972; Hick and McGill 1967; Oppy 1995; Plantinga 1965 and 1974b
Christian Philosophy . Daniel J. Hill and Randal D. Rauser. 2015.