Version 1 of #3530

I think your challenge asks for the wrong kind of thing. Deutsch’s “hard to vary” is a guideline for criticizing explanations, not a step by step decision algorithm. In this paper he says scientific methodology does not prescribe exact procedures, and that “better” explanations are not always totally rankable in a clean, mechanical way. “Hard to vary” mainly means avoiding explanations that can be tweaked to fit anything, because then they explain nothing, so the lack of a universal scoring program does not refute the idea.

THE LOGIC OF EXPERIMENTAL TESTS, PARTICULARLY OF EVERETTIAN QUANTUM THEORY

https://www.constructortheory.org/portfolio/logic-experimental-tests/

From the Paper:

An explanation is better the more it is constrained by the explicanda and by other good explanations,[5] but we shall not need precise criteria here; we shall only need the following: that an explanation is bad (or worse than a rival or variant explanation) to the extent that…

• (i)

  it seems not to account for its explicanda; or

• (ii)

  it seems to conflict with explanations that are otherwise good; or

• (iii)

  it could easily be adapted to account for anything (so it explains nothing).