Ontological Arguments
Briefly - What is an Ontological Argument?
• Ontological arguments are arguments that try to prove from the concept of God
alone, that God exists.
Anselm’s Ontological Argument
Context
• Our first Ontological argument begins in 1078 with St. Anselm of Canterbury
(1033–1109).
That than which nothing greater can be conceived - Anselm’s Proslogion II (1078)
• In his Proslogion II (1078), Anselm claims that God is: ‘That than which nothing
greater can be conceived’ and from this definition, God must exist.
• He arrives at this conclusion by stating the following:
It cannot exist in the intellect alone - Anselm’s Proslogion II (1078)
• ‘We believe [God] to be something than which nothing greater can be thought. The
Fool when he hears “something than which nothing greater can be thought,”
understands what he hears, and what he understands is in his intellect.
• (But) it cannot exist in the intellect alone. For if it exists only in the intellect, it
can be thought to exist also in reality, which is greater.
Something than which no greater can be thought exists both in the intellect and in
reality - Anselm’s Proslogion II (1078)
• If therefore it exists only in the intellect, this same thing than which a greater cannot
be thought, is a thing than which a greater can be thought. But this surely cannot be.
So, something than which no greater can be thought exists both in the intellect
and in reality’.
• (Charlesworth 1965, 116, translation).
, Formalised Argument
1. A being than which nothing greater can be conceived (henceforth: ABTWNGCBC)
exists in the mind.
2. Either ABTWNGCBC exists only in the mind or ABTWNGCBC exists in reality
also.
3. A being that exists in the mind AND reality is greater than a being that only exists
in the mind.
4. Since, if a ABTWNGCBC exists only in the mind, there is something that can be
conceived of that is greater than ABTWNGCBC, namely a ABTWNGCBC that
exists in reality.
5. But we cannot imagine something that is greater than God - a being greater than
the greatest possible being is contradictory.
6. Therefore, God exists both in mind and in reality.
Premise 1: A being than which nothing greater can be conceived exists in the mind.
• To claim that something exists in the mind, is to claim that we have a concept of
it.
• For example, we have a concept of a unicorn, therefore unicorns exist in the
mind.
• Whereas a round square, is not something we have a concept of (as it is not
logically possible) and so a round square does not exist in the mind.
• Some philosophers have argued that even this premise is wrong: that the
concept of God is not coherent nor logically possible.
• In order to give Anselm a chance and not begin another essay about whether
the concept of God is even possible, we shall assume that it is and leave that
question for another time.
Premise 2: Either ABTWNGCBC exists only in the mind or ABTWNGCBC exists in
reality also
Briefly - What is an Ontological Argument?
• Ontological arguments are arguments that try to prove from the concept of God
alone, that God exists.
Anselm’s Ontological Argument
Context
• Our first Ontological argument begins in 1078 with St. Anselm of Canterbury
(1033–1109).
That than which nothing greater can be conceived - Anselm’s Proslogion II (1078)
• In his Proslogion II (1078), Anselm claims that God is: ‘That than which nothing
greater can be conceived’ and from this definition, God must exist.
• He arrives at this conclusion by stating the following:
It cannot exist in the intellect alone - Anselm’s Proslogion II (1078)
• ‘We believe [God] to be something than which nothing greater can be thought. The
Fool when he hears “something than which nothing greater can be thought,”
understands what he hears, and what he understands is in his intellect.
• (But) it cannot exist in the intellect alone. For if it exists only in the intellect, it
can be thought to exist also in reality, which is greater.
Something than which no greater can be thought exists both in the intellect and in
reality - Anselm’s Proslogion II (1078)
• If therefore it exists only in the intellect, this same thing than which a greater cannot
be thought, is a thing than which a greater can be thought. But this surely cannot be.
So, something than which no greater can be thought exists both in the intellect
and in reality’.
• (Charlesworth 1965, 116, translation).
, Formalised Argument
1. A being than which nothing greater can be conceived (henceforth: ABTWNGCBC)
exists in the mind.
2. Either ABTWNGCBC exists only in the mind or ABTWNGCBC exists in reality
also.
3. A being that exists in the mind AND reality is greater than a being that only exists
in the mind.
4. Since, if a ABTWNGCBC exists only in the mind, there is something that can be
conceived of that is greater than ABTWNGCBC, namely a ABTWNGCBC that
exists in reality.
5. But we cannot imagine something that is greater than God - a being greater than
the greatest possible being is contradictory.
6. Therefore, God exists both in mind and in reality.
Premise 1: A being than which nothing greater can be conceived exists in the mind.
• To claim that something exists in the mind, is to claim that we have a concept of
it.
• For example, we have a concept of a unicorn, therefore unicorns exist in the
mind.
• Whereas a round square, is not something we have a concept of (as it is not
logically possible) and so a round square does not exist in the mind.
• Some philosophers have argued that even this premise is wrong: that the
concept of God is not coherent nor logically possible.
• In order to give Anselm a chance and not begin another essay about whether
the concept of God is even possible, we shall assume that it is and leave that
question for another time.
Premise 2: Either ABTWNGCBC exists only in the mind or ABTWNGCBC exists in
reality also
