Theme 2C: Deductive arguments: Challenges to the ontological argument

Gaunilo's Challenge

A critique of Anselm's ontological argument arguing that understanding in the mind is different from true existence.

Reductio ad Absurdum

A principle used by Gaunilo to demonstrate the weakness of Anselm's definition by arguing it could apply to an imaginary perfect island.

TTWNGCBT

An acronym standing for 'that than which nothing greater can be thought', used in Anselm's ontological argument.

Kant's Triangle Analogy

Kant's argument that just because something can be logically defined (like a triangle having three angles) doesn’t mean it exists.

Existence as a Predicate

Kant's assertion that existence is not a defining characteristic or predicate of God.

Intrinsic Maximum

A concept debated by Anselm and Gaunilo concerning whether God can possess a maximum quality that cannot be exceeded.

A Priori Reasoning

A type of reasoning that involves deduction from general principles, central to the debate on the ontological argument.

Kant's 100 Thalers Example

A critique illustrating that the existence of objects does not add value to their concept, as imaginary and real items have the same value.

Brian Davies Quote

“According to Gaunilo, if Anselm is correct then it is not only God’s existence that can be established by reasoning akin to Anselm’s.”

Gaunilo's Island Argument

An analogy used by Gaunilo to show that if Anselm's reasoning is valid, one could also argue for the existence of a 'most excellent island', which is nonsensical.

Kant's View on Being

Kant argued that 'being' is not a real predicate, meaning it does not add to our understanding of what something is.

Immanuel Kant's Assertion

“To posit a triangle, and yet to reject its three angles, is self-contradictory; but there is no contradiction in rejecting the triangle together with its three angles.”

Debate on God's Existence

The discussion surrounding whether Anselm's ontological argument or Kant's critiques provide a more convincing position on God's existence.