  One of the hallmarks of Descartes’ version of the ontological argument is its simplicity. Indeed, it reads more like the report of an intuition than a formal proof. Descartes underscores the simplicity of his demonstration by comparing it to the way we ordinarily establish very basic truths in arithmetic and geometry, such as that the number two is even or that the sum of the angles of a triangle is equal to the sum of two right angles. We intuit such truths directly by inspecting our clear and distinct ideas of the number two and of a triangle. So, likewise, we are able to attain knowledge of God’s existence simply by apprehending that necessary existence is included in the clear and distinct idea of a supremely perfect being. As Descartes writes in the Fifth Meditation: