Born in the Thracian town of Abcera, Protagoras spent most of his adult life in Athens. We can find no absolute truth, he held, but only truths that hold for given men under given conditions.
Different truths can hold for different people at different times.
Truth, goodness, and beauty are subjective and relative. Second, because perceptions vary with the previous experiences of the perceiver, they will vary from person to person. Third, what is considered to be true will be, in part, culturally determined because one's culture influences one's experiences. Because his central concerns were problems related to human existence, Socrates has sometimes been called the first existential philosopher. Socrates lived by all these principles.