One of the great exchanges in the Fourth Gospel comes when Jesus says he came to testify to the truth and Pilate asks in response "What is truth?"

What the evangelist means is that truth is not the criterion we use to determine how we will speak and deal with one another. He means that we shape our lies so that others will accept them and give us the response we want -- including their political support. After Pilate asks his question, he says to the crowd "I find no guilt in this man." 

The evangelist's point, which is often overlooked by pious exegesis, is that neither he nor the people could long survive if they had to speak the truth. Crowds cheer for the politicians who tell us the lies we want to hear, until we don't want to hear them any more.