The earliest documentation of critical thinking are the teachings of Socrates recorded by Plato. Socrates established the fact that one cannot depend upon those in 'authority' to have sound knowledge and insight. He demonstrated that persons may have power and high position and yet be deeply confused and irrational. He established the importance of asking deep questions that probe profoundly into thinking before we accept ideas as worthy of belief. He established the importance of seeking evidence, closely examining reasoning and assumptions, analyzing basic concepts, and tracing out implications not only of what is said but of what is done as well. His method of questioning is now known as 'Socratic questioning' and is the best known critical thinking teaching strategy. In his mode of questioning, Socrates highlighted the need for thinking for clarity and logical consistency. Socrates asked people questions to reveal their irrational thinking or lack of reliable knowledge. Socrates demonstrated that having authority does not ensure accurate knowledge. He established the method of questioning beliefs, closely inspecting assumptions and relying on evidence and sound rationale. Plato recorded Socrates' teachings and carried on the tradition of critical thinking. Aristotle and subsequent Greek skeptics refined Socrates' teachings, using systematic thinking and asking questions to ascertain the true nature of reality beyond the way things appear from a glance.