At a time when “Alternative facts” has become a new buzzword, and politicians and media in many countries seem comfortable telling provable falsehoods, I am reminded of this passage from a speech by the Greek orator Demosthenes:
οὐδὲν γὰρ ἔσθ᾽ ὅ τι μεῖζον ἂν ὑμᾶς ἀδικήσειέ τις ἢ ψευδῆ λέγων. οἷς γάρ ἐστ᾽ ἐν λόγοις ἡ πολιτεία, πῶς, ἂν οὗτοι μὴ ἀληθεῖς ὦσιν, ἀσφαλῶς ἔστι πολιτεύεσθαι;
There is nothing which wrongs you, the people, more than telling lies. After all, when the government is based on words, if those words are not true, how can we be properly governed?
~Demosthenes 19 On the False Embassy, section 184