For Christians, living in a culture that has abandoned absolute truth and reason as its foundation means freedom to speak the truth about biblical truths crucial to our witness and influence within the culture. Jesus’ prayer to His Father in John 17 focuses on our role as witnesses who are not of the world (that is, not motivated or controlled by the world’s priorities), but who are in the world, where we are kept from the evil one (John 17:14-16). Jesus went on to pray, “Sanctify them in the truth; your word is truth. As you sent me into the world, so I have sent them into the world” (John 17:17-18). For at least 150 of our country’s 247 years of existence, Christianity was the main influencer in how judgments were made about right and wrong. We are now in a post-truth world where personal autonomy and the satisfaction of the self are the chief aims of culture. In his book, “The Rise and Triumph of the Modern Self,” Carl Truman writes that the modern world “is one in which the transcendent purpose collapses into the immanent and in which given purpose collapses into any purpose I choose to create or decide for myself.” In this world, truth becomes whatever we determine it to be apart from the facts that define reality. We are now living in a world where reality is in constant flux, tossed back and forth by the whims of individual desires.