You've lifted a phrase without respect to its context. The "settled precepts of science" include the Scientific Method...a self-correcting discipline of research. The phrase does not mean that the book is closed by any means on the theories of our origins. As we accumulate more data, hypotheses and theories are refined, redefined, or discarded as needed.
I think that if you look at the context, you cannot help but see that the particular "settled precept" in question there was not the scientific method at all, but a naturalistic presupposition that the laity are not allowed to question.