Come up with a testable hypothesis regarding God's existence, and prove it to be true, and we'd HAVE to acknowledge God's role in our origins.
I suppose if that were possible it would have been done already. What sort of hypothesis would have to be proven true for you to accept it? According to the author's own definition of modern science supernatural explanations are not allowed. So how do you prove the existence of a supernatural being when supernatural explanations are not allowed, again, by definition.