What do they mean when they say the lobes of the brain are "arbitrarily" divided or positioned?

Question

Are they saying it's "arbitrary" because specific things like perception or whatever can happen in multiple parts of the brain? or are they saying it's "arbitrary" because if the frontal lobe had been placed on the side it would work just as well? thanks..

Answer 1

mostly cause there is no definite place in the brain that divides the brain from the frontal lobes and parietal lobes for example. the division occurs through function of particular areas or through anatomical markers on the brain itself.