  The derivation of FUNC essentially consists in the construction of an observable (i.e. f(Q)) via an operator (i.e., f(Q)) from the probability distribution of a variable (i.e. f(v(Q)) which number in turn is constructed from another variable, (i.e. v(Q)). Now, instead of denying that v(Q) exists in all cases (as the first option (5.1) would have it), we can reject that the existence of a number α and the construction of f(Q) automatically lead to an observable, i.e. we reject VR. This amounts to rejecting that for every self-adjoint operator, there is a well-defined observable.