No one should take as truth those who say truth is not knowable because then that truth would be unknown. I am not personally educated enough to know if relativity as discovered by Einstein is a basis for the relative nature of modern beliefs. I have heard there is a similarity. But for me I do not need to understand which I am too lazy not too unintelligent to do these relativity special and general to feel I can make an assessment about relativity as regards morals. Perhaps the Heisenberg Uncertainty Principle which may not have to do with Einstein is relevant to the discussion of relative ethics being that truth would appear to change with the observer and his method of observing but I am honestly out of my element when it comes to science. However, I think that the truth of the Bible is straight-forward enough to knock relativity out without exhaustively exploring relativity’s origins.
The Bible has a very strong record after years and years of attacks of all sorts which have perhaps undermined some peoples’ beliefs but not the bedrock truth of the word as transmitted through 40 some authors over hundreds of years. Numerous scrolls and records have brought faithfully down to us the complete word of God with no errors of any consequence even as I believe no errors at all. A strong mind can adequately explain any supposed discrepancy in the Bible. Even those things which are difficult to explain are if one waits long enough in one’s life explainable eventually by some turn in archaeology or textual analysis of a brighter mind or when explained by the Holy Ghost. To anyone who believes in the Apocrypha I challenge anyone to compare these books to the other books in the Bible. I think you will find they contradict and are not substantive enough as truth to be joined with the rest of scripture. There are other books as well especially the Gospel of Thomas which is no gospel at all when compared to the sturdy backbone of the canonical gospels.
The truth is out there to quote the X-files. But will you find it? You will if you seek it with all your heart and all your mind and all your strength. Ask God to reveal the truth and prudently and soberly study the evidence of scripture.