- Science can only be explanation: asserting what is there in reality.
- The only purpose of formalism, predictions, and interpretation is to express explanatory theories about what is there in reality, not merely predictions about human perceptions.
- Restricting science to the latter would be arbitrary and intolerably parochial.
Concerning the development and practice of quantum mechanics Deutsch says:
- It is assumed that in order to discover the true quantum-dynamical equations of the world, you have to enact a certain ritual.
- First you have to invent a theory that you know to be false, using a traditional formalism and laws that were refuted a century ago.
- Then you subject this theory to a formal process known as quantization (which for these purposes includes renormalization).
- And that’s supposed to be your quantum theory: a classical ghost in a tacked-on quantum shell.
- In other words, the true explanation of the world is supposed to be obtained by the mechanical transformation of a false theory, without any new explanation being added.
- This is almost magical thinking.
- How far could Newtonian physics have been developed if everyone had taken for granted that there had to be a ghost of Kepler in every Newtonian theory—that the only valid solutions of Newtonian equations were those based on conic sections, because Kepler’s Laws had those. And because the early successes of Newtonian theory had them too?
The logic about Schrödinger's linear multi-d equation then is:
- Interpretations must be made to give the equation a meaning.
- All interpretations are basically equivalent.
- One interpretation is MWI.
- MWI is absurd non-physics.
- Linear multi-d Schrödinger equation does not describe physics.