Before 529 a. d. plato and his followers founded the academy. Justinian only wanted his society to be centered on christianity. In 529 a. d. justinian shut down the school. Give specific geographical locations of philosophy during that period. Spread across various european nations including greece, rome, and great britain. True knowledge (there are not a lot of things you can prove 100%) False knowledge (if you do not know what"s true, how do you know what"s false) Uncertain or doubtful knowledge: we only know a certain amount of knowledge. Gradually eliminate uncertainty one doubtful element at a time. Completely reject all knowledge which is uncertain. Phil 1500 final study guide: very radical approach. He said that we should get rid of all knowledge that is uncertain. Then we should build our knowledge based on true knowledge only. We believe some areas in our knowledge to be certain while others to be not.