 One further aspect that is characteristic for Heisenberg and that prima facie does not fit with the theory of decoherence, is that Heisenberg does not take quantum states as fundamental. For him, Schrödinger’s notion of a ‘state’ was just a mathematical artifact that is convenient for calculating transition probabilities between values of (measured) observables. This can also be seen as underpinning the movability of the cut: there is no matter of fact about when the collapse takes place, and all that matters physically are the transition probabilities between values of observables. This view is still compatible with decoherence, however, as long as one sees the role of the quantum state there as again just a convenient tool for calculating transition probabilities (say, in a decoherent histories  framework).[34]