There is absolute truth and that truth transcends the relativity of human knowing. There is more knowledge than we know to be known.
What God has said is absolutely true.
If we wish to know that truth, truly, our only way is to know the One who knows absolutely and this mean we must adopt an attitude that we are going to submit to God and believe what reason cannot do.
We can know truth, of course not absolutely, but we can know its true truly, even if we only know it partially and imperfectly.
God / Well, This is What I Think
Of course the atheist and the agnostic can say that is your “presupposition” (if they know what that word means) at us, and they do, but we can point out as well that they are presupposing that God has not spoken.
And if they say “all truth is relative” really can say nothing, for if all truth is relative, then the statement that all truth is relative must be relative, which means that no such absolute statement can be made.
So what do you think about that agnostic?
Here is the difference between the Bible and the agnostic approach regards knowledge as the the place of origin or the earliest know history of something only begins who are finite and relative, and therefore then “truth” can only be a relative term. i.e. you can only compare to something else, not absolute)
But whereas the bible recognizes One who transcends relative knowledge and knows absolute truth and He speaks to His people so they may know it (The Bible)