Rodin, there’s no other reason for you to believe it. No known facts support it and far beyond that, it makes no sense. Taken literally, biblical theology is preposterous. It doesn’t even make a good fairy tale, and its values taken as a whole are atrocious.
When you cite McDowell, the response you’ll get from people here will consist mainly of rolling eyes, though you may not see them roll. An old high school friend sent me his Evidence That Demands a Verdict in 2001. Because she was a good friend with a kind heart, I took the time to read it. My review, dated July 4, 2001, is still on Amazon. You can narrow your search by limiting it to the one-star reviews. Intellectually, the book is trash, and the reasons for that are (1) McDowell is practicing apologetics and (2) even within that field, he’s not very good at it: he’s trying to justify a conclusion, instead of looking at the evidence and reasoning through to the most reasonable conclusion. The method is completely backward, and of all the people who’ve ever done apologetics, McDowell is not someone to cite to anyone with a decent education or any substantial intelligence.