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It does sound like Deutsch thinks all these different criteria boil down to being about hard vs easy to vary, see #3814.

Not according to Deutsch. He says hard to vary is epistemologically fundamental, that all progress is based on it. For example, he phrases testability in terms of hard to vary (BoI chapter 1):

When a formerly good explanation has been falsified by new observations, it is no longer a good explanation, because the problem has expanded to include those observations. Thus the standard scientific methodology of dropping theories when refuted by experiment is implied by the requirement for good explanations.

He also says that “good explanations [are] essential to science…” (thanks @tom-nassis for finding this quote). Recall that a good explanation is one that is hard to vary.

For Deutsch, hard to vary is the key mode of criticism, not just one of many.

It does sound like Deutsch thinks all these different criteria boil down to being about hard vs easy to vary, see #3807.

The quote may be false, but I don’t see how it’s misleading. I’m not quoting Deutsch in isolation or cherry-picking information or anything like that.

Liberty responded (1:39:46) that that quote is misleading because it makes it sound like hard to vary is the only criterion people use when making decisions, which can’t be true. There are other criteria, like “consistency with data”, “logical consistency”, “fitting in with existing theories”, etc.

I’m fine allowing user input to sidestep the creativity problem, see #3802.

I’m not saying hard to vary is a decision-making method. I’m saying it’s an integral part of Deutsch’s decision-making method. As I write in my article:

He argues that “we should choose between [explanations] according to how good they are…: how hard to vary.”

Liberty said (at 1:38:39) hard to vary isn’t a method of decision-making. It’s a factor people take into account when they make decisions, but decision-making itself is a creative process.

Not according to Deutsch. He says hard to vary is epistemologically fundamental, that all progress is based on it. For example, he phrases testability in terms of hard to vary (BoI chapter 1):

When a formerly good explanation has been falsified by new observations, it is no longer a good explanation, because the problem has expanded to include those observations. Thus the standard scientific methodology of dropping theories when refuted by experiment is implied by the requirement for good explanations.

For Deutsch, hard to vary is the key mode of criticism, not just one of many.

fundamental

@zelalem-mekonnen suggested during a space (37:36) that hard to vary is just one mode of criticism.

But calling a theory ‘good’ sounds like an endorsement. Deutsch also writes (BoI chapter 10) that a “superb” theory is “exceedingly hard to vary”. Ultimately we’d have to ask him, but for now, given the strength and positivity of those terms, I think it’s fair to conclude that he means ‘hard to vary’ as an endorsement.

Even if we allow creative user input, eg a score for the quality of an explanation, we run into all kinds of open questions, such as what upper and lower limits to use for the score, and unexpected behavior, such as criticisms pushing an explanation’s score beyond those limits.

Huh, no. I said you found a level where the epistemology is unproblematic to specify and turned that into Veritula. I said the opposite. You misunderstood me.

As I write in my article:

… Popper did formalize/specify much of his epistemology, such as the notions of empirical content and degrees of falsifiability. So why couldn’t Deutsch formalize the steps for finding the quality of a given explanation?

Deutsch’s yardstick applies to computational tasks. It’s not meant for other things. It’s not clear to me that the criterion of democracy is a computational task.

Yes, many ideas fail Deutsch’s yardstick. But so what? That doesn’t make things better.

@dirk-meulenbelt suggested in a space (at 21:30) that a bunch of epistemology is underspecified. There are many epistemological concepts (like criterion of democracy, falsifiability, etc.) that we don’t know enough about to express in code.

Veritula and hard to vary are different in this regard. Deutsch claims that ‘hard to vary’ is epistemologically fundamental, that it’s at the core of rationality, and that all progress is made by choosing between explanations based on how hard to vary they are. In other words, he suggests (though only vaguely) a decision-making method.

Veritula has a different decision-making method: one of criticizing ideas and adopting only those with no pending criticisms. That decision-making method is fully specified, with zero vagueness or open questions (that I’m aware of).

Veritula does not pre-specify ahead of time what criticisms people can submit, this is true. But that’s not a problem. It’d be like asking Deutsch to specify ahead of time what explanations people can judge to be easy or hard to vary. That’s not the specification that’s lacking with hard to vary.

During a space, starting at around 15:00, @dirk-meulenbelt suggested that Veritula suffers from underspecification: it does not specify which kinds of criticisms users can submit. But there are lots, like Occam’s razor, hard to vary, lack of testability, etc.

Since I criticize Deutsch’s ‘hard to vary’ criterion for being underspecified, Veritula shouldn’t be underspecified either.

(Correct me if I misunderstood you here, @dirk-meulenbelt.)

The ancient Greeks might have found the Persephone myth extremely hard to vary, eg due to cultural constraints. They wouldn’t have agreed that one could just swap out Persephone for someone else.

But then the ease with which a criticism could be varied might have no effect on its parent. So why even bother having a notion of ‘easiness to vary’ at that point?

What if we simply clamp the score at 0?

Even so, if a criticism gets score -10, that will push the parent theory’s score above 0.

But calling a theory ‘good’ sounds like an endorsement. Deutsch also writes (BoI chapter 10) that a “superb” theory is “exceedingly hard to vary”. Ultimately we’d have to ask him, but for now I think it’s fair to conclude that he means ‘hard to vary’ as an endorsement.

@lola-trimble suggested during a space that a theory is hard to vary if it’s not easy to vary. So the maximum score would be 0, not +1,000 or whatever. In which case ‘hard to vary’ isn’t an endorsement.