Protagoras：Man is the measure of all things

His exposure to many different societies, with lots of different customs, laws and religions, no doubt impressed upon him the vast latitude of ideas that the human mind could accept as true, Himself a teacher of Pericles, he showed the great leader the extent to which religious and moral codes were based not upon nature or some god-given truth but on socially constructed conventions. Rhetoric, tha art of persuasive speech, could and should therefore, according to him, be used to influence people's opinions and change them in ways that great leaders like Pericles could see would be best, at least relative to the interests of the society.

他暴露于许多不同的社会，许多不同的风俗、法律和宗教，无疑会给他留下广阔的思想，让人类的心灵能够接受这些想法。他本人就是伯里克利的一位教师，他向这位伟大的领袖表明，宗教和道德准则并非建立在自然或某些上帝赋予的真理的基础上，而是建立在社会建构的习俗的基础上。修辞学是一门具有说服力的演讲艺术，因此，在他看来，修辞学可以而且应该被用来影响人们的思想，并以像伯里克利这样的伟大领袖所认为的最好的方式来改变人们的观点，至少是与社会利益有关的方式来改变人们。