1. Criticisms of the Ontological Argument
Thomas Aquinas, Immanuel Kant, David Hume, GE Moore
Bertrand Russell

2. Aquinas Human reason is fallible
We cannot fully comprehend God – God is beyond human understanding
A Priori knowledge is inadequate for gaining knowledge of God
Proof of God’s existence must come from inductive arguments based on A Posteriori knowledge

3. Predicates? Bananas are yellow Rhinos have horns
Kant claimed that a predicate tells us something about the subject – it adds to our idea of what the subject is like.
To say “God exists” tells us nothing about God whereas God is angry does.
Bananas are yellow
Rhinos have horns
Giraffes have long necks
Snowflakes melt
God is angry
God exists

4. Kant’s Objection
“existence is not a predicate” - it is not the same as red, green, large, small, happy, sad
While it is impossible to separate subject from predicate in analytic statements,
Unicorn Horn
It is possible to deny the existence of both the subject & the predicate.
The most we can infer is that if unicorns exist, they necessarily have horns
Same is true of God: if there is a God, he necessarily exists.

5. David Hume Hume is an empiricist
‘Knowledge’ must be provable using scientific methods
Evidence is needed to back up claims
No such thing as “necessary” existence – everything that exists is contingent.
He also said existence is not a predicate

6. Some tame tigers do not growl Some tame tigers do not exist
G.E. Moore
Some tame tigers do not growl
Some tame tigers do not exist
GE Moore reinforced what Kant argued
“Existence” does not work in the same way as other predicates.
“Existence” is a term used to refer to things existing in the universe.

7. Cows are brown and exist
Bertrand Russell
The term “existence” refers to something which exists in the spacio-temporal world
Cows are brown
Cows are brown and exist
The second statement tells us nothing more than the 1st statement.
“existence” is not part of the description of a thing – it is an indication of its extension to reality.
Whether dragons exist or not has no impact on my idea of what a dragon is

8. Russell cont… Men exist SantaClaus is a man
The grammatical structure of a statement does not indicate its validity.
Men exist
SantaClaus is a man
Therefore Santa Claus exists
Syllogism
If we are to talk about something existing, we need to find evidence for it in the real (spacio-temporal) world