 That said, there are theorists who maintain not only that some conscious states in a subject are unified but that all conscious states must be unified. Bayne and Chalmers (2003: 24; Bayne 2010: ch. 1.4) call this the unity thesis: necessarily, any set of conscious states of a subject at a time is unified. As we saw, Brentano probably held this view. Hill (1991) does, too. Scepticism about this view would be weaker than either of the two kinds of scepticism about unified consciousness that we just examined.