the mathematical representations (i.e., vectors and operators) with predictions, is trough the Born rule (and possibly through the EE rule as well). That is, the only way to extract a claim regarding what to expect with respect to the physical properties of a quantum system, from the fact that its quantum state is such and such, is via the Born rule (an possibly the EE rule as well). In this regard, the Born and EE rules play the role of *physical interpretations* of the mathematical formalism of standard quantum mechanics. That is, they constitute the dictionary that translates between the math and the world that the physics tries to describe.

But what happens if one decides to drop the Born rule and the collapse postulate, as is proposed, e.g., within the decoherence program in order to deal with the conceptual difficulties of quantum theory? Then one must necessarily substitute this interpretation of the mathematics of the formalism for something else. If one does not do that, then we do not have, properly speaking, a physical theory. That is, the link between the formalism and physical predictions is lost. Moreover, by considering a purely unitary formalism, i.e., by dropping the collapse 