 Another problem for the relational view is that it cannot easily handle cases of normal misperception, for example, the Muller-Lyer illusion. Campbell tells us that idiosyncrasies of the perceiver may affect phenomenal character, but he has no account to offer of cases in which something looks other than it is even to normal observers in normal circumstances. Here the scene before the eyes fails to capture the phenomenology. Brewer says that illusions are to be accounted for in terms of visually relevant similarities to paradigms of a kind of which the perceived object is not an instance. In the case of the Muller-Lyer, the paradigm is a pair of lines one longer and more distant than its plane, the other shorter and less distant. This proposal encounters various potential difficulties (Pautz 2010). For example, in the waterfall illusion, the water appears to be moving and not moving at the same time. Here there are no suitable paradigms in the real world. (See the entry on  the disjunctive theory of perception.)  