I am in gratitude to David Wells for his concise summary of postmodern epistemology.  Certainty itself is hacked away.

“The dichotomy which postmodern epistemology wants to force is one between knowing everything exhaustively or knowing nothing certainly at all.  And since it would be arrogant in the extreme to claim to know what God alone knows the only other option, it seems is to accept the fact that our knowledge is so socially conditioned, so determined by our own inability to escape our own reality, that we are left with no certain knowledge of reality at all.  This is the epistemological position accepted by Richard Middleton and Brian Walsh. All attempts at `getting reality’ right, they say, have proved to be failures and Christians should concede as much.”  Above All Earthly Powers, p. 158 (footnote 46)

For encouragement that we can be certain in what we know about God, see I John 2:26-27, “I write these things to you about those who are trying to deceive you.  But the anointing that you received from him abides in you, and you have no need that anyone should teach you.  But as his anointing teaches you about evreything- and is true and is no lie,  just as it has taught you- abide in him” and also I John 5:20, “And we know that the Son of God has come and has given us understanding, so that we may know him who is true; and we are in him who is true, in his Son Jesus Christ.  He is the true God and eternal life” and Luke 1:3-5 “it seemed good to me… to write an orderly account for you… that you may have certainty concerning the things you have been taught.”