Descartes and HisThoughts Regarding Dreams Vs Reality

In first mediation Descartes ponders on the idea of what is real and what is a dream; he concludes that anything thing he can doubt is false and therefor a dream. After establishing the existence of the dream world he tries to figure out who is responsible for tricking him into this false world. He ponders on the idea that God could be responsible for tricking him, but quickly disregards that assumption believing that God, who represents everything that is good, could not deceive him; and concludes that is has to be a faulty demon who is tricking him. In the second meditation he ponders on his own existence, after assuming the existence of the dream world and the evil demon trickster in the first meditation. By the end of the mediation he determines that no matter what the demon does to trick him into doubting his existence, at that moment when he thinks he knows that he exists. By the third meditation he is certain of two things first there is a dream world that is controlled by a d emon, and second he knows that he exists. In the third mediation he ponders on the existence of god; and Descartes ultimately achieves that god exists because he has this idea of a prefect being that he did not learn about or imagine so this idea of god was put in him by a superior perfect being. That brings us to the fourth meditation where Descartes tries to figure out why do we have faults and make wrong decisions, errors. By this point Descartes know a few things to be certain first he