Ontology is the branch of philosophy that studies concepts such as existence, being, becoming, and reality. It includes the questions of how entities are grouped into basic categories and which of these entities exist on the most fundamental level.

We present here the ontological arguments from past and present. How did reality come into existence? Using logical constructs basic we present their basic premises and conclusions. Like philosophy, ontology is under constant debate and usually receives strong reactions in persons dependent on their worldview. This is a walk through currently known ontological arguments in a series of posts. What do you think? Please submit comments below.

See also: Reasons for Intelligent Design

Anselm, Proslogian II Ontological Arguments

1) [Suppose] God exists in the understanding but not in reality.
2) Existence in reality is greater than existence in the understanding alone.
3) A being having all of God’s properties plus existence in reality can be conceived.
4) A being having all of God’s properties plus existence in reality is greater than God. (1, 2)
5) A being greater than God can be conceived. (3, 4)
6) It is false that a being greater than God can be conceived. (def. of “God”)
7) So, it is false that God exists in the understanding but not in reality. (1, 5, 6)
8) So, God exists in reality.

● A. D. Smith, Anselm’s Other Argument (Harvard, 2014).

Alternative:
1) A being than which no greater can be conceived exists at least in the mind.
2) It is greater to exist in reality than to exist only in the mind.
3) So, a being than which no greater can be conceived exists not only in the mid but also in reality.
4) So, God exists.

“I clearly see that existence can no more be separated from the essence of God than can its having three
angles equal to two right angles be separated from the essence of a triangle, or the idea of a mountain from the idea of a valley; so there is no less absurdity in thinking of a God (a supremely perfect being) who lacks existence than in thinking of a mountain without a valley.” – Descartes

Descartes Ontological Arguments


1) If I cannot conceive of x without y, then y belongs to the nature of x.
2) I cannot conceive of a supremely perfect being without existence.
3) Therefore, existence belongs to the nature of a supremely perfect being. (1, 2)
4) If existence belongs to the nature of a supremely perfect being, then a supremely perfect being exists.
5) A supremely perfect being exists. (3, 4)

See Also: Does the Cosmos Explain God? and Is There a Necessary Being?