 However, that response is only partial. It might show that introspection alone does not rule out the possibility that macrophenomenal properties are constituted by quiddities or by quiddities and structure. But the response does not explain how macrophenomenal properties might result from such constituents. Although some explanations have been proposed (e.g., Rosenberg 2004, 2015), many regard the combination problem for Russellian monism as unsolved and serious (see the entry  panpsychism;  Brüntrup and Jaskolla 2017; Chalmers 2017).