Abstract: The realist view of the physical world represents it as something whose existence is logically independent of the human mind and philosophically fundamental. If we retain allegiance to this view, then even when we set aside the problem of perception, there turns out to be a severe limitation on what we can empirically discover about the nature of the world. For while we can find out much about the structure and organization of the realist's world, we have no way of discovering the nature of its forms of intrinsic content. Thus, we have no way of discovering what, beyond their properties of spatial structure, the occupants of space are like in themselves, nor any way of discovering what, beyond its geometrical structure, the spatial medium is like in itself. Not only are the forms of intrinsic physical content empirically inscrutable, but we cannot, in physical terms, even envisage what they might be.

Keywords: realist, physical world, empirically discover, structure, organization, occupants, space, geometrical structure,