Truth excludes its opposite. The person who denies the exclusive nature of truth is also making a truth claim. The question is whether the truth claim being made can be sustained by the tests for truth.
By Ravi Zacharias.
Excerpted from: Geisler, N. L., & Hoffman, P. K. (2001). Why I am a Christian : Leading thinkers explain why they believe (268). Grand Rapids, Mich.: Baker Books.