"Modern visions of the Ontological Argument are more successful than early versions"

   So, Anselm argued that firstly that existence is perfection and that anything that exists will be greater than anything that does not exist. Also, it is necessary existence that is a perfection, anything that has necessary existence is greater than that which has contingent existence.        

   While St. Thomas Aquinas (1224-1274) believed that God's existence is self-evident, he rejected the idea that it can be deduced from claims about the concept of God. Aquinas argued, plausibly enough, that "not everyone who hears this word 'God' understands it to signify something than which nothing greater can be thought, seeing that some have believed God to be a body." The idea here is that, since different people have different concepts of God, this argument works, if at all, only to convince those who define the notion of God in the same way. On Aquinas's view, even if we assume that everyone shares the same concept of God as a being than which none greater can be imagined, "it does not therefore follow that he understands what the word signifies exists actually, but only that it exists mentally."

   René Descartes (1596-1650) resurrected Anselm’s argument, stating that the idea of God as a perfect being requires existence. Just as a triangle requires the idea of 3 angles adding up to 180º. If we are to call God “that than which nothing greater can be conceived” it must have all supreme perfections – one being existence.

   Hume (1711-1776) argued that although God could exist, he could also not exist, nothing necessarily exists and so even God is contingent, he rejected Anselm’s argument purely on the basis that there was no such thing as necessary existence.

   Kant (1724-1804) also criticised Anselm’s argument by arguing that the notion of existence is being treated as the wrong logical type. Concepts, as a logical matter, are defined entirely in terms of logical predicates. Since existence isn't a logical predicate, it doesn't belong to the concept of God; it rather affirms that the existence of something that satisfies the predicates defining the concept of God. While Kant's criticism is phrased in terms of the logic of predicates, it also makes a plausible metaphysical point. Existence is not a property, rather it is a precondition for the instantiation of properties in the following sense: it is not possible for a non-existent thing to instantiate any properties because there is nothing to which a property can stick. Existence isn't a great-making property because it is not a property at all; it is rather a metaphysically necessary condition for the instantiation of any properties. So in summary, Kant argued that existence was not a predicate and that necessary existence does not work either.

   The last early philosopher to object was Bertrand Russell (1872-1970). He argued that there were different types of existence, such as if you have an idea of a cow you can go out and find one. However, if you have an idea of a unicorn, that image exists only in the mind. Russell argues that people are confusing first and second order predicates; so while the cow has first order predicates such as hoofs and ears (material properties), the unicorn only has second order predicates ( conceptual properties). So, he argued that God can only be thought of in terms of second order predicates.

   Once Anselm’s argument had been subjected to so many 17th -18th century criticisms it was left virtually untouched until the 20th century when modern philosophers decided to attempt to create a more plausible version of the ontological argument. The main contributors to this were realist Alvin Plantigna (1932-) and anti-realist Norman Malcolm (1911-1990) who argued for the existence of God.

   Norman Malcolm focused on Anselm’s second stage of the argument in which God is impossible to be thought of as not existing. This has meant a shift from the idea of logical necessity to the idea of existential necessity. Basically his argument was formed from 7 premises leading to the conclusion that God exists. He argued that

1. God, as the greatest conceivable being, cannot be a limited being.
2. Therefore, if God doesn’t exist, he can neither be caused to come into existence nor merely happen to come into existence. Both cases would impose a limitation on God and contradict premise 1.
3. Similarly, if God does exist, he cannot merely come into existence or cease to exist. Both cases would impose a limitation on God and so contradict premise 1.
4. The implication of premise 2 is that, if God does not exist, his existence is impossible; and the implication if premise 3 is that, if he does exist, his existence is necessary.
5. Either God does not exist or he does exist.
6. Therefore God’s existence is either impossible or necessary.
7. God’s existence is not impossible (i.e. the notion of his existence is not self-contradictory.)
8. Therefore, God necessarily exists. 

John Hick is the principal objector to this argument because he believes Malcolm jumps from factual necessity to logical necessity.

   Perhaps the most influential of contemporary modal arguments is Plantinga's version. Plantinga begins by defining two properties, the property of maximal greatness and the property of maximal excellence, as follows;

1. A being is maximally excellent in a world W if and only if it is omnipotent, omniscient, and morally perfect in W; and  
2. A being is maximally great in a world W if and only if it is maximally excellent in every possible world.

Thus, maximal greatness entails existence in every possible world: since a being that is maximally great at W is omnipotent at every possible world and non-existent beings can't be omnipotent, it follows that a maximally great being exists in every logically possible world. Accordingly, the aim is to show that a maximally great being exists in some world W because it immediately follows from this claim that such a being exists in every world, including our own. But notice that the claim that a maximally great being exists in some world is logically equivalent to the claim that the concept of a maximally great being is not self-contradictory; for the only things that don't exist in any possible world are things that are conceptually defined in terms of contradictory properties. There is no logically possible world in which a square circle exists (given the relevant concepts) because the property of being square is inconsistent with the property of being circular. Since, on Plantinga's view, the concept of a maximally great being is consistent and hence possibly instantiated, it follows that such a being, i.e., God, exists in every possible world. However, as with many arguments, there is a problem with this. His argument is not valid and he constructs a syllogism. This argument shows that if it is possible that there be a greatest possible being and if that idea includes necessary existence, then in fact there is a being that exists in every world and in some world has a degree of greatness that is nowhere excelled. Of course it doesn’t follow that the being in question has this degree of greatness in this world. So, the argument restated by Plantinga was,

1. There is a possible world where there is a being of maximal greatness.
2. It has maximal excellence. (as part of maximal greatness.)
3. If maximal excellence and maximal greatness exist in our world then,
4. There is a God.

This is now certainly a valid argument leading Plantinga to the conclusion that he was correct. However, Plantinga’s argument could argue the non-existence of God, or the existence of a malevolent God if the properties were changed.

   So, it is not right to say that modern versions of the Ontological Argument are better than Anselm’s. So far they are more successful in that they have not been criticised so much but they had an original argument plus original criticisms to construct their arguments from. However, an argument that is constructed purely by using logic and that is no way empirical is not going to be successful at all to the masses – theists already have the faith needed, others are going to need more sound proof. Some philosophers such as Findlay have made the Ontological Argument also work to prove the non-existence of God:-

• If God’s existence was contingent, then God couldn’t be God
• If God’s non-existence is necessary (could not, not exist), then God’s existence is impossible since nothing capable of non-existence can exist.

This implies that the Ontological Argument is not going to really hold together, if an argument can be used both ways then it is not really strong enough. Also, any formulation of the Ontological Argument amounts to tautology. Any definition of God can be taken, for example if God is defined as a necessary being, then God necessarily exists translates as “A necessary being exists necessarily.” This statement is analytic but doesn’t state anything new.