"As originally put forward , there were four cardinal premises (of phrenology), namely that: (1) the brain is the material instrument through which the mind holds intercourse with the outer world ; (2) the mind entails a congeries of discrete mental faculties each with its own specific center or organ; (3) the size of each organ corresponds with the functional efficiency of each faculty; and (4) the development of the organ is reflected in the shape, size and irregularities of the encompassing cranium."