Hard to Vary or Hardly Usable?
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With an account, you can revise, criticize, and comment on ideas.My critique of David Deutsch’s The Beginning of Infinity as a programmer. In short, his ‘hard to vary’ criterion at the core of his epistemology is fatally underspecified and impossible to apply.
Deutsch says that one should adopt explanations based on how hard they are to change without impacting their ability to explain what they claim to explain. The hardest-to-change explanation is the best and should be adopted. But he doesn’t say how to figure out which is hardest to change.
A decision-making method is a computational task. He says you haven’t understood a computational task if you can’t program it. He can’t program the steps for finding out how ‘hard to vary’ an explanation is, if only because those steps are underspecified. There are too many open questions.
So by his own yardstick, he hasn’t understood his epistemology.
You will find that and many more criticisms here: https://blog.dennishackethal.com/posts/hard-to-vary-or-hardly-usable
Neil Hudson says in response to the bounty:
I wonder if this objection risks making a Hilbertian mistake: assuming that an objective criterion must provide a universal decision procedure. Gödel taught us not to equate objectivity with decidability. Why should HTV need to algorithmically rank every pair of explanations to be meaningful?
Not a mathematician but AFAIK, Hilbert basically asked if we could make a machine that answers every math question correctly. The answer to that is ‘no’. But an algorithm for rational decision-making isn’t about that.
Neil replies fallibility means the criterion must be able to get answers wrong or not deliver an answer at all sometimes. And if that’s the case, not any pair should be needed. Otherwise, “reliably compare” would be a demand for infallibility.
I reply:
The word “reliably” refers to the claim in BoI that ppl search for HTV explanations “systematically”; that they follow some yet-to-be-specified system to form preferences this way.
The system/program, being man-made, would of course be fallible. Still, since BoI says HTV is at the heart of all rational endeavors, the system must be universal. Hence the requirement for any pair.