Arguments based on reason
A posteriori Arguments that draw conclusions based on observation through
arguments experience
Ontological To do with the nature of existence
A priori arguments Arguments that draw conclusions through the use of reason
Contingent Depending on other things
Necessary existence Existence which does not depend on anything else
Predicate A term which describes a distinctive characteristic of something
Epistemic distance A distance in knowledge and understanding
Logical fallacy Reasoning that has a flaw in its structure
The ontological argument claims that simply by thinking logically about what we understand to be the
nature of God and what the implications of that must be, we can deduce that there must be such a
God. It claims that is impossible for God to not exist as it is in his nature to exist; existence is part of
the definition of God. The argument is a priori which means that it is working from first principles and
definitions in an attempt to demonstrate the existence of God. It is also a deductive argument as it is
based in logic rather than sense experience. According to the ontological argument, everything other
than God is contingent and under any other circumstances, everything would cease to exist. There
was no time where God did not exist and there is nothing that could happen to stop God from existing.
Anselm and the ontological argument
Anselm (1033-1109) was an Archbishop of Canterbury and produced an ontological argument from
the perspective of someone with faith searching understanding rather than to convince others of
God’s existence.
In the first form of the argument, Anselm begins by defining God as ‘that than which nothing greater
can be thought’. Whether we believe in God or not, he argued that this is what everyone meant by
‘God’. He is understood to be the most perfect being and that nothing could surpass him. Anselm
argued that if we have an idea of a God who is perfect in every way, where nothing could be greater,
then this God must exist in reality. This is because a God that exists solely in our heads is inferior to a
God that exists in reality, and we have already agreed that God is not inferior in any way. So, God
must exist, in order to reach his own definition.
In the second form of the argument, he argued that it would be impossible for God to not exist.
Contingent beings are inferior to necessary beings. Here, Anselm argues that God must exist
because a necessary being cannot fail to exist; only contingent beings can fail to exist.
1. God is that than which nothing greater can be thought.
A real, existent being would be greater than an imaginary, illusory being.
Therefore, the concept of God is surpassed by an actual, existent God.
2. God is that than which nothing greater can be thought.
Because God is unsurpassable in every way, God must have a necessary existence.
Therefore, God exists necessarily.
One way of understanding the ontological argument draws a distinction between two different kinds of
proposition (a statement which proposes something, or says that such-and-such is the case). This is
particularly associated with Kant’s criticisms.
An analytic proposition is one which is true by definition – bachelors are unmarried men. This does
not need to be proven, it can be arrived at through deduction. Anselm claims that ‘God exists’ is
analytic – the concept of God includes the concept of existence, and without existence, the term ‘God’
would not apply. A synthetic proposition is one that adds to our understanding – this is not deductive,
but arrived at through sense experience. For example, the ‘corner shop sells newspapers’ is synthetic
as the concept of a corner shop does not include the concept of selling newspapers.
A posteriori Arguments that draw conclusions based on observation through
arguments experience
Ontological To do with the nature of existence
A priori arguments Arguments that draw conclusions through the use of reason
Contingent Depending on other things
Necessary existence Existence which does not depend on anything else
Predicate A term which describes a distinctive characteristic of something
Epistemic distance A distance in knowledge and understanding
Logical fallacy Reasoning that has a flaw in its structure
The ontological argument claims that simply by thinking logically about what we understand to be the
nature of God and what the implications of that must be, we can deduce that there must be such a
God. It claims that is impossible for God to not exist as it is in his nature to exist; existence is part of
the definition of God. The argument is a priori which means that it is working from first principles and
definitions in an attempt to demonstrate the existence of God. It is also a deductive argument as it is
based in logic rather than sense experience. According to the ontological argument, everything other
than God is contingent and under any other circumstances, everything would cease to exist. There
was no time where God did not exist and there is nothing that could happen to stop God from existing.
Anselm and the ontological argument
Anselm (1033-1109) was an Archbishop of Canterbury and produced an ontological argument from
the perspective of someone with faith searching understanding rather than to convince others of
God’s existence.
In the first form of the argument, Anselm begins by defining God as ‘that than which nothing greater
can be thought’. Whether we believe in God or not, he argued that this is what everyone meant by
‘God’. He is understood to be the most perfect being and that nothing could surpass him. Anselm
argued that if we have an idea of a God who is perfect in every way, where nothing could be greater,
then this God must exist in reality. This is because a God that exists solely in our heads is inferior to a
God that exists in reality, and we have already agreed that God is not inferior in any way. So, God
must exist, in order to reach his own definition.
In the second form of the argument, he argued that it would be impossible for God to not exist.
Contingent beings are inferior to necessary beings. Here, Anselm argues that God must exist
because a necessary being cannot fail to exist; only contingent beings can fail to exist.
1. God is that than which nothing greater can be thought.
A real, existent being would be greater than an imaginary, illusory being.
Therefore, the concept of God is surpassed by an actual, existent God.
2. God is that than which nothing greater can be thought.
Because God is unsurpassable in every way, God must have a necessary existence.
Therefore, God exists necessarily.
One way of understanding the ontological argument draws a distinction between two different kinds of
proposition (a statement which proposes something, or says that such-and-such is the case). This is
particularly associated with Kant’s criticisms.
An analytic proposition is one which is true by definition – bachelors are unmarried men. This does
not need to be proven, it can be arrived at through deduction. Anselm claims that ‘God exists’ is
analytic – the concept of God includes the concept of existence, and without existence, the term ‘God’
would not apply. A synthetic proposition is one that adds to our understanding – this is not deductive,
but arrived at through sense experience. For example, the ‘corner shop sells newspapers’ is synthetic
as the concept of a corner shop does not include the concept of selling newspapers.
