Paradox

218 A BRIEF HISTORY OF THE PARADOXthe paradox fails to get off the ground. The riddle of theinverted image is an example of a paradox that was raised byexperiments and resolved by conceptual analysis.According to Descartes, your body is determined by thelaws of nature. But your mind is free. Indeed, Descartesblamed all errors on human willfulness. We jump to conclusionsout of laziness and desire. We should be ashamedbecause God’s goodness ensures that he has given us enoughresources to ascertain the true nature of reality. If God hadrigged up the world in the way feared by the skeptics, thenGod would be a deceiver—which is incompatible with God’sbeneficence and power. God must have given us a fairopportunity to learn about the nature of the external worldbeyond our minds. Descartes’s Discourse on Method showsphilosophers and scientists how to exploit this opportunity.In the Meditations Descartes endeavors to prove all thisfrom an indubitable basis. The possibility of dreams andillusions drives him to a purely internal perspective. If he canprove that God exists, Descartes will prove that we can knowthe external world. But until God is proved, Descartes can onlyuse the data available to his immediate consciousness. ThusDescartes is confined to a priori proofs of God’s existence.Descartes’s first proof portrays his idea of God as an infallibletrace of God himself. All other sources for the idea are methodicallyexcluded: Descartes could not have obtained that ideafrom himself because he is finite. Nor can an idea of God resultfrom adding two finite ideas (in the way Descartes gets the ideaof a unicorn by combining the idea of a horn and the idea of ahorse). Adding finite things together only produces finitethings. Nor can the idea of God come from subtracting one ideafrom another. Infinity is not a subtraction from finitude. So theidea of God must have come from God himself. Descartes also