Protagoras was an early Sophist and arguably the first postmodern thinker. If we describe the traditional thinker as one who derives values from the ancient Homeric and Hesiodic myths (μύθος) and the modern thinker as anti-traditional, looking for natural scientific explanations (λόγος), then we can define postmodern as one whose values come from (νόμος), the norms that are created by a given community as their culture. Where Aristotle applied some universal notions of ethical values in developing the constitution of thens, Protagoras famously travelled to different city-states and asked them for their cultural norms and conventions so he could incorporate them in a constitution. This was attacked by Socrates and Plato as "relativism," the idea that "what is true is what is true for me." Protagoras saw that "man is the measure of all things." But the word he used for "things" was not τὰ ὄντα, the "things that exist," or "entities," the "beings" (das Seinde) of Martin Heidegger. Protagoras used the word χρηήατα, loosely translatable as "things of value," or "needs."
πάντων χρημάτων μέτρον ἐστιν ἂνθροπος, τῶν μὲν ὂντων ὡς ἐστιν, τῶν δε οὐκ ὂντων ὡς οὐκ ἐστιν