  Descartes’ contemporaries would have been surprised by this last remark. While reviewing an earlier version of the ontological argument, Aquinas had rejected the claim that God’s existence is self-evident, at least with respect to us. He argued that what is self-evident cannot be denied without contradiction, but God’s existence can be denied. Indeed, the proverbial fool says in his heart “There is no God” (Psalm 53.1).