And nowhere does God tell us that truth is subjective. Truth is objective and logical, and it is found in and restricted to the sixty-six books of the Bible. The problem here is that when one divorces logic from epistemology, he is left with skepticism. And skepticism is self-contradictory, for it asserts with certainty that nothing can be known for certain. The words of God and Satan mean the same thing.
Rational discourse is impossible.
Neither God nor the world can be known, leaving us in a state of uncertainty. Herein we have a Christian epistemology, a Christian philosophy, a Christian worldview set before us. But this is not the starting point. A system cannot start unless it starts. And the first principle or starting point or axiom in Christian dogmatism is the Word of God, biblical revelation.