Descartes
French philosopher who developed a version of the Ontological Argument using geometric necessity. Descartes argued that existence is essential to God's nature as three sides are essential to a triangle. His systematic method of doubt sought indubitability; God's existence grounds his metaphysics.
Real World
Descartes' 'I think, therefore I am' from his 1641 Meditations remains so culturally influential that it appears on philosophy department walls worldwide — and his proof of God was essential to rebuilding knowledge after his method of radical doubt.
Exam Focus
Use the triangle analogy precisely: existence belongs to God's essence as three angles belong to a triangle's definition.
How well did you know this?