 Quantum fundamentalists must indeed be ready to explain why the macroscopic world appears classical. An alternative to von Neumann’s projection postulate is the claim that the formalism should be read literally and that measurements (classical outcomes) do not describe the world as it really is. But there are ontological cost, which is significant to some. In one interpretation the world divides into as many worlds as there are possible measurement outcomes each time a system is observed or interacts with another system. Other fundamentalists had hoped that the decoherence program might come up with an appropriate explanation. The decoherence theory sees entanglement to exist not only between object and the measurement but also as something which includes the environment. If Bohr had known the idea of decoherence, he would probably have had no objection to it, as several authors have pointed to decoherence as a natural dynamical extension of his view that measurements is an irreversible amplification process (Schlosshauer and Camilleri 2015, 2017; Bächtold 2017, Tanona 2017; and Dieks 2017). However, it is generally agreed that decoherence does not solve the measurement problem (Bacciagaluppi 2016; Zinkernagel 2011). This might seems as if von Neumann’s projection postulate has to be reintroduced as a dynamical factor to explain why one and only one measurement result appears. However, as Dieks (2017) argues, Bohr’s interpretation could be understood as a non-collapse interpretation, since “the superposition does not have an empirical meaning independently of its interpretation via classically described experiments, so no replacement by another mathematical state is needed. We just have to interpret the formulas correctly.” In spite of that there is no general agreement to what extent Bohr opposed quantum fundamentalism.