anselm ontological argument

main aim

to prove the existence of God based on the concept of God

premise one

the concept of being than which non greater can be conceived (GCB) exists as a coherent concept in the mind

premise twos

suppose that the GCB exists only in the mind and not in reality

premise three

a being that exists in the mind and in reality is greater than a being that exists only in the mind

conclusion one

based on our previous supposition, there is something greater than the GCB

conclusion

however this is a contradiction so we must reject our aforementioned supposition, so the GCB must exist in the mind and in reality

development

all the premises are justified a priori as a form of rational intuition

as the argument is deductive the conclusion should follow necessary