modern ontological arguments

descartes

• Doesn’t attempt to claim that God exists in the understanding and so is not vulnerable to the accusation of confusing the concept of God with God himself or presuppose a particular faith -> his argument is grounded in his belief in innate ideas 

• He argued that the foundation of knowledge was intuition. 

•  Intuition operates through direct intellectual awareness, not the indirect analysis of linguistic representation employed by logical terms. 

• Intuition provides absolute certainty. 

• We can bring ideas before our mind and apprehend truths about them due to the psychological character in which they strike us. 

descartes’ proof

P1 – I have an idea of a supremely perfect being which contains all perfections 
P2 – Existence is a perfection 
C3 – God exists 

plantiga’s onto argument

• developed the ontological argument further in his book ‘The Nature of Necessity (1974)’.  

• He used a type of thinking called “modal logic” which involves imagining alternative possible worlds. 

•  For example, although our world is a possible world, there is another possible world in which Alvin Plantinga became a farmer rather than a philosopher.  

• If God can exist in one possible world, then God actually exists in all possible worlds, as God has necessary existence - (Possible World Theory / Modal logic) 

plantiga’s proof

•  P1: There is a possible world in which there exists a being with maximal greatness.  

• P2: A being has maximal greatness in a world only if it exists in every possible world.  

• C: A being of maximal greatness (“God”) must exist in this world, the actual world