The word ‘ontos’ means ‘being.’
The Ontological argument thus attempts to prove the existence of God a priori by focusing on the nature of his existence or being.
St. Anslem (1033-1109) was the Archbishop of Canterbury.
His argument was first presented in the form of a prayer in his book, ‘Proslogion,’ directed at the fool of the Psalm (Psalm 14) who says in his heart that there is no God.
Anselm's Two Forms
There are two forms to Anslem’s Ontological argument:
1/ God can be defined as ‘that than which nothing greater can be conceived’
2/ We can all conceive of a perfect being in our minds, however we can also conceive of an even greater being that exists both in our minds (in intellectu) and in reality (in re)
3/ Beings that exist in both the mind (in intellectu) and reality (in re) are greater than those that only exist in the mind (in intellectu)
4/ Therefore God must exist both in the mind (in intellectu) and in reality (in re) otherwise something greater in reality (in re) could be perceived.
It is impossible to conceive of a God not existing (John Hick agreed):
1/ A necessary being is greater than a contingent being since a contingent being depends on something else for its existence and we can be thought of as not existing
2/ God can be defined as ‘that than which nothing greater can be conceived’ and therefore God must be a necessary being – his existence does not depend on other forms
3/ It is impossible to conceive of a necessary being not existing
4/ Therefore God must necessarily exist
Descartes formulated his own Ontological argument for the existence of God based on perfection as a necessary attribute of God:
1/ God possesses all perfections
2/ Existence is a perfection
3/ Therefore God exists
ANALOGY OF A TRIANGLE
The analogy of a triangle can be used to explain Descartes’ form of the Ontological argument.
A triangle has predicates (necessary characteristics); for example, all of its internal angles must add up to 180°. If these predicates are removed the triangle is no longer a triangle.
Anslem said, in the same way, existence is a predicate of God.
Immanuel Kant opposed Descartes’ form of the Ontological argument and argued that existence is not a predicate of perfection.
Adding ‘and exists’ to the end of the word ‘bachelor’ does not change its literal definition
Gaunilo in his book ‘On Behalf of the Fool’ used the analogy of a perfect island to illustrate the absurdity of the first form of Anslem’s Ontological argument.
He cited the example in which one could conceive of ‘the most perfect island’ in their mind. According to Anslem, existence is a part of perfection; therefore, following Anselm’s line of argument, the image of a perfect island that exists in one’s mind must necessarily exist in reality because its existence presupposes its perfection.
If it didn’t exist in reality the grottiest island that exists in reality would be better than the ‘perfect’ island that exists only in the mind.
ANSLEM’S COUNTER ARGUMENT
Anslem’s response to Gaunilos’s criticism was to maintain that he was not arguing about contingent beings such as islands, but beings that existed necessarily; ‘that than which nothing greater can be conceived.’
Islands have no ‘intrinsic maxim’ and can always be bettered – according to John Hick, notations of perfection are subjective.
Anslem thus formulated the second form of his Ontological argument to counter this criticism.