The ontological argument is associated mainly with St Anselm and René Descartes. Anselm (1033 – 1109) was the first to devise the argument through a series of works named "Proslogion", which attempted to prove both the nature and existence of God. Anslem’s version originates from the meaning of the word ‘God’ by definition. He states that God is a being “that than which nothing greater can be conceived.” Anselm’s argument is that if God as a perfect being exists in our mind he must exist in reality as a God that did not exist could not be perfect.
Descartes (1596 – 1650) later develops the argument in central texts including the Principles of Philosophy. His version of the argument suports Anselm as he too states that to be perfect God must exist. Howerver it does differs slightly. Descartes' argument is also based on the theory of innate ideas. He does not solely rely on a definition of God but rather on an innate idea of the essence of God. Descartes' version summarised is; God's existence is inferred from the fact that necessary existence is contained in the clear and distinct idea of a supremely perfect being, and that God must exist because existence is a predicate of a perfect being. Therefore God must exist to avoid being self-contradictory. Descartes demonstrates that trying to imagine God without the predicate of existence is like trying to imagine a triangle without three sides. Both Descartes and Anselm stated that this tactic could not be applied to anything someone could imagine to exist, such as faries, but can only be applied to a necssary being; a being that must exist and exists independant of cause. God is such a being, he can not not exist.
Two modern day suporters of theory are Norman Malcom and Alvin Plantinga. Malcom said that Gods existence was either impossible or necessary and, assuming that the concept of God is neither absurd or contradictory, God must be necessary and therefore exist. Plantinga similarly states that a God with ‘maximal greatness’; one that is omnipotent, omniscient, omnibeevolent and moraly perfect has to exist in this world and any other possible worlds.
One classical objection to the ontological argument was first leveled by Gaunilo against Anselm's version, writing an immediate response in "Proslogion 2". Gaunilo stated that if someone was to describe a perfect island, untouched by man and lost somewhere, and then state that it must exist you would be a fool to believe him. The simple fact that this person has envisaged this island does not mean that this island exists. Gaunilo is trying to criticise how Anselm moves from a definition of God to presuming his existence.
Immanuel Kant also opposed the ontological argument. He believed that it is based on too many assumptions and points out that the argument assumes what it is trying to prove from the beginning. He states that a person can define something anyway they want to but it does not necessarily mean that this definition is true and that Anselm and Descartes’ definition of necessary presupposes that existence is included, but proof cannot be based on such presumptions. David Hume similarly stated that the ontological argument involves a prior belief; someone must believe in God and assume that he is many things as well as real before they believe that he is necessary and therefore must exist.
Aquinas also commented on the ontological argument. His critique was so devistating that it was largely the cause of the ontological argument dying out for several centuries (before being brought back by Descartes). Aquinas agrees that it is necessary for God to exist as the world has to have a cause and be dependant on something to keep it in motion. However he also states that it is impossible for a human being to truly know God’s essence and therefore we can never know if God’s essence includes existence. Aquinas believed that we could only know that God is necessary, and so exists, by examining the world around us, and not the definition of God, as we can never truly define God.
- How true is the claim that the ontological argument proves conclusively that God exists?
The ontological argument is very clever in many ways, as it cannot be disproved in the way that other arguments can, such as the argument from religious experience, as it does not use evidence that can be invalidated. It not only says that God does exist but that there is no reason to question the existence of God in the first place and anyone who does so simply does not understand God. It highlights the otherness of and perfection of God, which is a cornerstone of the Christian faith.
However many would argue that they understand the concept of God perfectly but do not believe that God exists. Even those who do believe in God and his existence, such as Aquinas, find fault with the Argument. Critics have said that the argument’s fundaments are simply assumptions. It assumes that God cannot be self-contradictory; Hume states that God cannot be impossible and ‘necessary’. However there are many obvious contradictions of God. If God is all loving and all-powerful why do horrible things happen in the world? Can got create a stone that is so heavy he cannot lift it? If you say yes then he is not all powerful because he cannot lift the stone, if you say no then he is limited because he cannot make the stone. To many people God is many different and contradictory things. However supporters of the argument state that God is unique and therefore the rules of the contingent universe do not apply to him in the same way, and he can be many things at one time, but primarily he must exist.
Kant agrees to some extent. He states that if God does exist then he would exist perfectly and be necessary just as for a triangle to exist it must have three sides. However you can apply a similar statement to other things; if unicorns do exist they would have horns, if fairies do exist they would have wings. Describing something does not mean it exists. Gaunilo’s argument that you cannot define things into existence is very similar to Kant’s criticism. By simply explaining what God is does not make God exist, just as explaining the imaginary desert island does not mean it is physically real. Supporters argue that it is different as God is a ‘necessary being’. However the idea that God is necessary is another assumption. It assumes that the universe had to have had a cause and needs something to maintain it, and this is God, something that cannot be proven to be true.
This lack of physical proof means that to many the ontological argument is weak and pointless if trying to convince an atheist. Empiricists say that this argument does not involve empirical evidence or experiences we can rely on and without this the, argument becomes useless. Just as Hume argued it relies on a prior faith and understanding of what God is which includes the understanding and belief that God has to exist beyond doubt. If someone does not believe that God’s existence is an actual quality of God, in the way that blue eyes would be, then it cannot be a predicate and the statement ‘God exists’ cannot be an analytic one, therefore the argument breaks down.
The argument is only successful in proving God’s existence to a person that already believes in God. Just like Kant someone can agree on a definition of God, they can agree that if God exists he would be perfect and that perfection would include necessity, but merely a definition can not erase the ‘if’ from a persons mind if it is there. Therefore the argument does not prove conclusively that God exists, as it does not offer any form of physical proof, which is largely the only way of persuading a non-believer to believe, which is what arguments for existence of God essentially aim to do.
