The book of Genesis is an "oral history" as recorded by Moses via divine inspiration (that goes all the way back TO THE BEGINNING).......Moses nor Gilgamesh nor "YOU" were around to give a 1st hand account of these events. Its the prima facie evidence found in the Holy Scriptures that can be tested by science and history found not to be lacking that gives credibility to the entire history recorded. Its a most difficult thing to prove that Sumer, Dilmun, Ugarit......proves that Gilgamesh PREDATEED "THE BEGINNING".
Over 90% of the Bible can be tested by History Actual and Applied Science and have never been debunked. Until someone can present Objective evidence that disproves this oral history.......it stands as truth, just as prima facie evidence found in court rooms stands until proven beyond doubt to be false.
If up to 90% of the scriptures cannot be subject to refutation though objective evidence.........why should the 10% that cannot be subject to first hand testing be dismissed as false? Answer: preconceived opinions based not on science or history but personal bias.
The prison system is filled with convicts that have been convicted on prima facie witness accounts that could not be dismissed via objective evidence beyond doubt........many are on death row.