How successful are ontological arguments?
Ontological arguments are a priori and seek to propound the reality of God, departing from
the concept of God, in an attempt to prove His existence through His definition. The term
‘ontological’, as coined by Immanuel Kant, literally means “to do with being”. Philosophers
such as Anselm and Descartes present their ontological arguments as being underpinned
by the statement ‘God exists’, suggesting that this must be correct through the idea that
the statement is true analytically.
Anselm, a Christian philosopher, employed his Basic Argument to ontologically argue for
God’s existence. The Basic Argument proposes that God is “that which nothing greater
can be conceived”, thus, as God exists as a concept in the minds of all, it can be said that
a God that exists in reality would be better than one limited to potentiality. Due to Anselm’s
definition of God, it must be that if God existed exclusively in the mind, the definition of
God would be false as there is an opportunity for a ‘greater’ being - one that exists in real-
ity. Therefore, God must exist in reality and not simply as a concept. The Basic Argument
is convincing in that it succeeds as a proof of God for all, regardless of whether one is a
Christian or an atheist, as it is true that all have a concept of God in their mind. However,
Anselm prefaces his argument with a presupposition of God’s existence, “For I do not seek
to understand in order that I may believe, but I believe in order to understand”, thereby
making his argument circular. This means that Anselm’s conclusion that God exists is al-
ready assumed in his initial premise, making the Basic Argument flawed. Furthermore, the
Catholic monk Gaunilo criticises Anselm “On behalf of the fool” arguing that Anselm’s ar-
gument is reductio ad absurdum, meaning that his logic must be wrong as it creates ab-
surd conclusions when applied elsewhere. This can be observed through the illustration of
a ‘perfect island’, using Anselm’s logic the ‘perfect island’ conceived in one’s mind cannot
be perfect as a real ‘perfect island’ would naturally be better, thus the ‘perfect island’ in the
mind must exist in reality. This is of course false and, as an imitation of the Basic Argu-
ment, it further invalidates Anselm’s ontological argument. Furthermore, Gaunilo is sup-
ported by Thomas Aquinas who adds that God’s existence is obvious to God himself but
cannot be proved ontologically, as Anselm seeks to do, as God’s nature simply cannot be
grasped by the human mind.
However, Anselm conceived a second form of argument, one that uses the same definition
for God as the Basic Argument to suggest that it is greater to be a necessary being than a
contingent being and, therefore, God must be a necessary being in order to satisfy the def-
inition that there is nothing greater than God. This argument is more successful and more
convincing than the Basic Argument in outlining God’s existence as it is not fallacious in
the same ways, and therefore is more difficult to refute. Descartes reinforces the strength
of ontological arguments by stating that a priori arguments are inherently better than a
posteriori arguments, like those that are cosmological or teleological, arguing that sense
evidence is not sufficient to determine the existence of God. Furthermore, Descartes’ Med-
itation 5 is an ontological argument derived from his definition of God as a “supremely per-
fect being”. From this definition, Descartes postulates that existence is a perfect quality
and God must possess all perfect qualities in order to be perfect himself, thus, God must
possess existence. Descartes utilises the illustration of a triangle to emphasise his point,
stating that just as a triangle must have three sides in order to be a triangle, God must
have existence to be God. This is a convincing argument as it emphasises that God and
existence cannot be separated, intensifying the argument that God does exist and support-
ing Anselm. However, Immanuel Kant criticises Descartes’ Meditation 5 by exposing that it
only works in proving God to those who already believe in God. This is seen through his
argument that if you already have a triangle then it must have 3 sides but if you do not
