Divisions of philosophy: epistemology what can you know, metaphysics what is real, ethics what should i do, what should i be, social political philosophy how should i be governed, aesthetics what is beautiful. Man is the measure of all things. You can never see what another person sees: separated by time and space. Relativism no other perception but your own: gorgias. Even if there is one, you can"t know it. Even if you can know it, you can"t communicate it because you use words: different takes on reality, eg. Socrates learn universal not particular; by function sophists are lost on the inspection of particulars have to categorize by function (argument used against gorgias) beauty is function. Unexamined life not worth living , examined life = what am i doing, why am i doing this. Objects/world itself mathematics world of form opinion (sophists) knowledge perfect knowledge.