The environment is now not correlated with the alternatives inside the box. Nevertheless there are still two orthogonal eigenstates, representing alternative decoherent histories of the full system, in one of which the cat is alive and in the other of which the cat is dead. 

There is no alternative in which only the cat is in a superposition of alive and dead. 

As discussed in [24], we can consider the state of our actual universe to be one or the other of the alternatives in Eq. (42), selected with probabilities given by | ψ no R | 2 and | ψ yes R | $^{2}$. But, even though one or the other alternative may be chosen as “the” state of the universe—and the cat certainly knows which one it is!—if the box is closed, this information is simply un- available to the environment outside the box. The outcome for E is thus the same regardless of what happens inside the box. 

Note that the above analysis is not changed if we presume that the intent to open the box is formulated in the brain of the experimenter sometime after the initiation of the experiment. Or if the experimenter is replaced with, say, a device that may randomly open the box during the run of the experiment. In all cases, by the end of the experimental period, the box will be either open or still closed. 

Whether the box is opened or remains closed, this example illustrates how a microscopic quantum event with orthogonal outcomes can be amplified to determine orthogonal eigen- states for an entire macroscopic system and its environment—and, conceptually, the entire universe. These orthogonal eigenstates represent a consistent set of alternative histories, in one of which the cat is alive and in the other of which the cat is dead. The alternatives of the cat being dead and alive are thus clear and classical. Indeed, the composite subsystem in the interior I of the box is already sufficient to provide the necessary decoherence of alternatives, regardless of whether this information can get outside of the box to its external environment. 

## VIII. CONCLUDING REMARKS 

As with any derivation, Zurek’s derivation of Born’s rule is based on a number of basic assumptions, as nicely elucidated by Schlosshaur and Fine [42] and further addressed by Zurek himself [34]. These assumptions condition the interpretation of the non-relativistic formalism used by Zurek, where two entangled systems are represented as evolving into a Schmidt state in which the individual states of the two systems are correlated. Clearly, sim- 

