 One can similarly argue from the linear dynamics and the properties of an ideal observer that if \(J\) repeats his spin measurement, he will end up with the sure-fire disposition to report that he got the same result for the second measurement as for the first (even when he did not in fact get an ordinary determinate result for either). Hence, it will appear to him that there has been a collapse of the quantum-mechanical state when there has been no collapse, splitting of worlds, or anything else that would produce an ordinary determinate measurement record. The subjective appearance of a collapse here is an illusion produced by the linear dynamics together with the observer’s dispositions.