I would say that Expert is simply a label and not a position, and that it is always realtive. It also may or may not correlate to correctness. One important point is that almost every expert gets left behind, often within his or her own life span.
But experts can be wrong as well as right. The weight of evidence always trumps the Expert.
On the Biblical/Moses issue, there are several major schools of thought. I would imagine there are as many or more experts that agree there were mutiple authors as those that think Moses wrote it. But again, the weight of the evidence seems to favor those who support the multi-authorship. The sole-authorship crowd seem to have nothing but tradition supporting their position.
Aslan is not a Tame Lion