When a society tears itself apart over beliefs it cannot justify, philosophy steps in to ask what it really means to know anything at all. 

Topics explored

• The 16th and 17th centuries were marked by intense religious fanaticism and violence (e.g., the Peasant Rebellion, Münster, the Thirty Years’ War).
• These events pushed thinkers to demand firmer foundations for belief—not mere authority or dogma.
• But agreement proved impossible: philosophers disagreed sharply about what counts as justification and what a belief must rest on to be considered rational.
• Meanwhile, ancient texts and ideas—especially from Plato and the skeptics—were being rediscovered, raising old questions in a new era.
• The lesson introduces epistemology, the study of knowledge, and frames the central issue: What makes a belief justified?
• Plato’s Justified True Belief (JTB) theory sets the stage, but Agrippa’s Regress Argument challenges whether justification is possible at all (the setup for the next steps in the course).
• Pyrrhonian skepticism reappears as a powerful alternative: suspend judgment to achieve ataraxia, tranquility free from dogmatic conflict.