Descartes' Ontological Argument

Descartes writes his argument from a sceptical stance, and it is similar to Anselm’s in that it begins with a definition of God, in this case as ‘the supremely perfect being’ (SPB). He goes on to describe the SPB as having all the perfections. He continues to say that existence is perfection, so God must therefore exist in order to fulfil his definition as the SPB. Descartes ends his argument by saying that God exists necessarily, or in other words, he possesses the perfect quality of existence.

Descartes uses the example of a triangle to illustrate his point. A triangle will always have three sides and its angles will always equal 180 degrees. Whether or not we have ever experienced a triangle, these facts will always be true of it. In the same way that a triangle and three sides are interlinked, God and existence also are linked as the nature of these two is immutable.

By describing existence as a predicate of the SPB, Descartes encounters the issue of the differentiation between possessing the quality of existence and actually existing in reality. 

Anselm's Ontological Argument and Gaunilo's Response

In this argument, Anselm starts by defining God as that than which nothing greater can be conceived (TTWNGCBC). He then goes on to say that everyone has an idea of God as TTWNGCBC as by using the word ‘God’ it demonstrates an understanding and recognition of the principle of God. This means that even the fool that "says in his heart, ‘there is no God'" (psalms 14:1 and 53:1) is contradicting himself as he is showing that he holds a concept of what God is. Anselm uses the example of the painter to further explain this point as the painter has an idea of a painting, which after he paints it exists not only in his mind but also reality. Anselm states that it is greater to exist in reality than in concept. In order for God to fulfil his definition as TTWNGCBC, he must exist in reality rather than just in concept. Therefore, God exists. 

However, Gaunilo responded to Anselm in his argument ‘on behalf of the fool’ which is a reduction ad abusrdem argument. Gaunilo used the concept of a perfect island ‘that than which nothing greater can be conceived’ to show how a word alone cannot explain its existence if we have not experienced it. He argued that just because you can conceive of something, does not mean it exists in reality.

Anselm developed his argument in order to overcome Gaunilo’s criticisms. He argues that comparing God to an island is an unfair comparison as an island is contingent (can be thought of to not exist) whereas God’s existence is necessary (cannot be thought of as not existing). Nothing on this Earth can be compared to God due to the contingent nature of it. A God who cannot be thought of as not existing is greater than a God who can be thought of as not existing; therefore, Anselm proves that God exists necessarily. 

Evil and the God of Love - John Hick

(Useful for the evil and suffering topic).

One of Hicks's arguments is that evil and suffering are created by God as a scheme of "soul-making", in order for humans to better themselves to be accepted into heaven. He states that development of the human soul has to occur in a world of distress as we cannot grow in a world where everything is already perfect.

There are a number of problems with John Hick's "soul-making" theodicy. Primarily, not all suffering and evil have benefits for the growth of human morality as the negative responses may outweigh the positive. For example, a young child dying may develop feelings of empathy and compassion, however the consequent sorrow and pain may prevent an individual in moral development and putting their trust in God.