You can't live postmodern!
If Christians are to communicate the gospel truth to today’s postmodern generations, we will likely have to do more than simply state the truth. In many cases, it will not suffice to hold forth our Bible and walk friends down the famous “Romans Road” series of evangelistic verses.
In addition, and often beforehand, we will need to answer questions such as, “Why should I accept that the Bible is true?” and, “That may be true for you, but why should it be true for anyone else?” These are questions concerning epistemology, that is, our beliefs and assumptions about knowledge and truth. Prior to giving our witness to Christian truth, we will often have to present clear Christian views about truth itself.
“Truth” is always held by actual persons, and those persons are deeply shaped by culture, language, heritage, and community. There will be differences, involving both strengths and weaknesses, in how a Westerner will read a certain passage of Scripture and how a sub-Saharan African Christian will read the same passage. For instance, the Westerner is more likely to emphasize the individualist and the African the corporate aspects of the passage.
Regardless of the question of absolute truth itself, postmodernity correctly points out that actual people are finite and therefore have a limited, subjective understanding of truth
Christians, in particular, believe that truth derives from and is revealed by God. Thus, the truth is authoritative. Here is where postmodernity parts company with historic Christianity, for the postmodern view rejects the reality of truth, positing an implicit (and in some cases, explicit) relativism in which nothing is really and finally true. Survey after survey shows that this mindset prevails in Western culture today. “Do you believe in absolute truth, or is all truth relative?” Clear majorities today, even among professing Christians, affirm the postmodern dogma that nothing is really, absolutely true.
Moreover, postmoderns steadfastly insist that even if there is the ultimate truth, finite and flawed men and women can never know the truth authoritatively. The postmodern junta now governing Western culture holds this relativism as its sole absolute: no one has the right to say that he possesses the truth absolutely so that others are absolutely wrong. There may be “my truth” and “your truth,” but the postmodern mind dogmatizes against anyone claiming dogmatically to possess the truth (except the postmodern dogma against said dogma).
The crisis of the postmodern position is that it cannot believe or live out its own claims. Postmodernity has nothing to believe, including its own unbelief, despite the aching need of humans to know and believe.
One professor made this point after his college class had united against him in insisting that nothing is ultimately true or morally wrong in an objective sense. The next day the professor informed the students that regardless of their performance on the exam they were all going to receive an F. The students objected in unison, “But that’s wrong!” and the professor’s point against relativism was made. No one can live it, and therefore no one really believes it. This is the crisis of truth in our postmodern times: our society dogmatically rejects truth in theory but cannot live that way in practice.
An evangelical Christian epistemology begins by affirming that truth corresponds to reality. The external world in which every individual lives is not a world we subjectively construct through our narrow experience. Rather, God created reality and upholds it by his ongoing providential rule.
The basis for this Christian doctrine of real truth is that God exists
Phillips, R. D. (2011). Can we know the truth?. (D. A. Carson & T. J. Keller, Eds.) (pp. 12–13). Wheaton, IL: Crossway.