  Finally, while the modal interpretation was designed to solve the measurement problem and reconcile quantum mechanics with special relativity, it faces challenges on both accounts.  First, in certain imprefect measurements (where there are imprefections in the coupling between the measured system and the pointer of the measurement apparatus and/or the pointer and the environment), modal interpretations that are based on the Schmidt biorthogonal-decomposition theorem (and more generally the spectral decomposition theorem) fail to account for definite measurement outcomes, in contradiction to our experience (see Bacciagaluppi and Hemmo 1996 and Bacciagaluppi 2000). For versions of the modal interpretations that seem to escape this problem, see Van Fraassen (1973, 1991), Bub (1992, 1997), Bene and Dieks (2002) and Berkovitz and Hemmo (2006a,b). Second, as we shall see in section 10.2, a number of no-go theorems challenge the view that modal interpretations could be genuinely relativistic.