Gaunilo

• He was an 11th Century monk
• He aimed to criticise Anselm's ontological argument
• He is most famous for his perfect island argument

Anselm of Canterbury

• Was the Arch Bishop of Canterbury
• (1033-1109)
• He was greatly influenced by plato and throughout his life wrote about the nature of God
• He is most famously known for his ontological argument

Descartes

• (1596-1650)
• Many philosophers see him as the founder of modern philosophy
• His most famous book is his Meditations of Philosophy
• Most famous for his ontological argument

Descartes' Ontological Argument

(The Background)

• Before presenting his argument Descartes concluded:
• God has placed in every person the idea of God. Descartes likened this idea to a trademark from a craftsman.
• He argued that God's existence is a truth somewhat similar to mathematics.
• Demonstrating God's existence is about showing that there is no reason to ever doubt that God exists.

Descarte's Ontological Argument

(Triangles)

• Descartes labelled a triangle as 'immutable'- meaning incapable of change.
• Descarte goes on to say that a triangle is a triangle whether it is understood by a person or not, if noone knew what it was it would still have three sides.
• According to Descartes part of God's nature is that he exists. This is immutable.
• For descartes the essence of God is that he exists and existence is a predicate fo God

Descartes Ontological Argument

(The argument)

1. God is a supremely perfect being
2. A property of perfection is existence
3. Therefore, God exists

Descartes Ontological Argument

(So why should we believe that God exists?)

Descarte Gives two answers:

1. If you study the idea of God enough it becomes obvious that God is necessarily perfect
2. Descarte insists that existence is a perfection therefore God must exist.

Gaunilo's response to Anselm's Argument

(Gaunilo's argument: Part 1)

Gaunilo argues that Anselm's argument is 'unintelligible'. Gaunilo suggests that the fool might reply to Anselm in the following way.

Gossip: The fool could have in mind all sorts of things that do not exist in reality. For example someone may have heard Gossip and chosen to believe it. Just because the fool has an idea of God does not mean it is a reliable one.

Gaunilo's response to Anselmn's argument

(The argument: Part 2)

Defining things in to existence: You can not define an idea in to existence.

Gaunilo's response to Anselmn's argument

(The argument: Part 3)

Gaunilo's island: His most famous argument is the perfect island argument. Anyone can think of a perfect paradise island, Gaunilo argues that whilst this can be concieved it does not exist. Gaunilo concludes that it is absurd to say that just because you have an idea of something it must exist, therefore either the argument is a joke, the man making the argument is a fool or the person believing the argument is a fool. 

Anselm's response to gaunilo's response to Anselm's Ontological argument

(The argument: Part1)

Anselm's response to gaunilo's response to Anselm's Ontological argument

(The argument: Part2)

Anselm's response to gaunilo's response to Anselm's Ontological argument

(The argument: Part 3)