[asdff]

Ideally, but once you are deep in a field what a field even is becomes murky. You have a biology paper you submit for review, but methodologically it's not really a biology paper, but maybe a statistics paper, or a computer science paper, or a theoretical math paper. Who reviews that paper, the person who knows the biology in question or the methods through and through? Sometimes the only person in the world who knows the theory and the technology in question the best is the author.