 A further aspect of the relation between decoherence and spontaneous collapse theories relates to the experimental testability of spontaneous collapse theories. Indeed, if we assume that collapse is a real physical process, decoherence will make it extremely difficult in practice to detect empirically when and where exactly spontaneous collapse takes place: on the one hand, decoherence makes it look as if collapse has taken place already, while on the other it makes it difficult to perform interference experiments to check whether collapse has not yet taken place. (See the nice discussion of this issue in Chapter 5 of Albert (1992)).