bhobba said: then the ensemble interpretation is kaputt

Why? There is a difference between an interpretation and a derivation.An interpretation of quantum mechanics relates the formalism to the actual informal practice of using quantum mechanics in our scientific culture.Thus it may use objects familiar from our culture without having to explain their working. It must only show that there is a consistent relation between theory and practice.** The minimal statistical interpretation (which you call the ensemble interpretation) does this for predicting the outcome of experiments. It is silent about the interpretation of quantum mechanics in the absence of measurements, and in particular about the interpretation of quantum physics applied to the far past before experiments were possible.I think that this is a is a serious gap, but since the interpretation is silent here it is not wrong or broken (kaputt), just very incomplete (as it should be for a ''minimal'' interpretation).** The Copenhagen interpretation that claims that nothing can be asserted in the absence of a measurement is also consistent, but it is part of the reason why quantum mechanics is considered to be weird - a tree fallen in the wood has fallen only after someone has seen it.** In a many-world interpretation anything goes, and at not even specifiable times the world splits and splits, completely unnoticed by us. This is already weird by conception.Thus neither interpretation is satisfactory.A derivation of quantum mechanics must derive quantum mechanics from general assumptions, and hence must be applicable to all of quantum mechanics.If it cannot derive how QM treats a harmonic oscillator it is worthless.If it needs measurement devices as inputs it is worthless, too, since it cannot explain why QM worked before the first human measured something.Hardy claims in his abstract that ''it is shown that quantum theory can be derived from five very reasonable axioms''. But his derivation fails on both accounts. He derives quantum information theory, not quantum mechanics.