 The central claim at the basis of RQM is therefore that: “different observers can give different accounts of the same set of events” (Rovelli 1996: 1643). Textbook quantum mechanics is a complete description of the perspective of a single observer, but it disregards the effect of this observer system on the perspective of other systems. RQM emphasises the fact that the observer itself behaves as a quantum system, when acting on other systems. The relation between perspectives is discussed below.