Descartes" suggestion about the assent box have in common: He grasps each one of them clearly and distinctly- as much as the notion that i exist. Whatever i clearly and distinctly grasp is true. In order to justify, descartes needs to rule out the existence of an evil demon who could deceive him about the truth of what is grasped clearly and distinctly. This is equivalent to a proof of the existence of a benevolent god. In my mind i find the idea of god. Show that it has to have been implanted in my mind by a being, different from my mind, that is at least as perfect as the being represented by the idea. Classification of the ideas found in my mind according to. Ordering of objects according to their formal reality. Only 1 and 2 are interesting when we want to prove the existence of an object external to our mind.