Meta question here: why does reference-class forecasting work at all?

Presumably, the process is that when you cluster objects by visible features, you also cluster all their invisible features too, and the invisible features are what determines the time evolution of those objects.

If the category boundary of the "reference class" is a simple one, then you can't fool yourself by interfering with the statistical correlation between visible and hidden attributes.

For example, reference class forecasting predicts that cryo will not work because cryo got clustered with all the theistic religious afterlives, and things like the alchemists' search for the Elixir of Life. The visible attribute we're clustering on is "actions that people believe will result in an infinite life, or >200 year life".

But a cryonics advocate might complain that this argument is trampling roughshod over all the careful inside view reasoning that cryonicists have done about why cryo is different than religion or superstition: namely that we have a scientific theory for what is going on.

If you drew the boundary around "Medical interventions that have a well accepted scientific theory backing them up", then cryo fares better. The different boundaries you can draw lead to focus upon different hidden attributes of the object in question: cryonics is like religion in some ways, but it is also like heart transplants.

Alter these reference classes even tiny bit, and the result you get is basically just the opposite. For cryonics, just use the reference class of cases where people thought either a) that technology X could prolong the life of the patient, or b) that technology X could preserve wanted items, or c) that technology X could restore wanted media. Comparing it to technologies like this seems much more reasonable than taking the single peculiar property of cryonics(that it could theoretically for the first time grant us immortality) and using only that as a reference class. You could use same argument of using the peculiar property as reference class against any developing technology and consistently reach ~0% chance for it, so it works as perfectly general counter argument too.

Coming of a new world seems more reasonable reference class for singularity, but you seem to be interpreting in a bit strickter way than I would. I'd rephrase that as reference class of enormous changes in society, and there has indeed been many of such. Also, we note that processing and spreading information has been crucial to many of these, so narrowing our reference class to crucial properties of singularity(which basically just means "huge change in society due to artifical being that is able to process information better than we are"), we actually gain opposite result than what you did.

We do have a fairly good track record of making artifical beings that replicate parts of human behavior, too.

The problem with a lot of faulty outside view arguments is that the choice of possible features to focus on is too rich. For a reference class to be a good explanation of the expected conclusion, it needs to be hard to vary. Otherwise, the game comes down to rationalization, and one may as well name "Things that are likely possible" as the reference class and be done with it.

"Now in some situations we have precise enough data that inside view might give correct answer - but for almost all such cases I'd expect outside view to be as usable and not far away in correctness."

Why? The above statement seems spectacularly wrong to me, and to be contradicted by all commonplace human experience, on a small scale or on a large scale.

"Reference class of predictions based on technology which isn't even remotely here has perhaps non-zero but still ridiculously tiny success rate."

What? Of such a tech, fairly well und... (read more)

This seems to me to argue yet again that we need to collect an explicit dataset of prior big long-term sci/tech based forecasts and how they turned out. If I assign a ~5+% chance to cryonics working, then for you to argue that goes against an outside view you need to show that substantially less than 5% of similar forecasts turned out to be wrong.

If you actually look a little deeper into cryonics you can find some more useful reference classes than "things promising eternal (or very long) life"

http://www.alcor.org/FAQs/faq01.html#evidence

1. Cells and organisms need not operate continuously to remain alive. Many living things, including human embryos, can be successfully cryopreserved and revived. Adult humans can survive cardiac arrest and cessation of brain activity during hypothermia for up to an hour without lasting harm. Other large animals have survived three hours of cardiac arrest n

I don't know if those are the right reference classes for prediction, but those two beliefs definitely fall into those two categories. That should set off some warning signals.

Most people seem to have a strong need to believe in life after death and godlike beings. Anything less than ironclad disproof leads them to strong belief. If you challenge their beliefs, they'll often vigorously demonstrate that these things are not impossible and declare victory. They ignore the distinction between "not impossible" and "highly likely" even wh... (read more)

It is not a good idea to try and predict the likelihood of the emergence of future technologies by noting how these technologies failed to emerge in the past. The reason is that cryonics, singularities, and the like, are very obviously more likely to exist in the future than they were in the past (due to the invention of other new technologies), and hence the past failures cease to be relevant as the years pass. Just prior to the successful invention of most new technologies, there were many failed attempts, and hence it would seem (looking backward and applying the same reasoning) that the technology is unlikely ever to be possible.

I think we should taboo the words "outside" and "inside" for purposes of this discussion. They obscure the actual reasoning processes being used, and they bring along analogies to situations that are qualitatively very different.

The main use of outside views is to argue that people with inside views are overconfident, presumably because they haven't considered enough failure modes or delays. Thus your reference class should include some details of the inside view.

Thus I reject your reference classes "things promising eternal life" and "beliefs in almost omnipotent good or evil beings" as not having inside views worth speaking of. "Predictions based on technology which isn't even remotely here" is OK.

Our proposed complicated object here is "cryonics, singularity, superhuman AI etc." and I'm looking for a twist that decomposes it into separate parts with obvious references classes of objects taw finds highly probable. (Maybe. There are other ways to Transform a problem.) How about this: take the set of people who think all of those things are decently likely, then for each person apply the outside view to find out how likely you should consider to be. Or instead of people use journals. Or instead take the set of people who think none of those... (read more)

Biting the outside view bullet like me, and assigning very low probability to them.

I am going to stop using the term 'bite the bullet'. It seems to be changing meaning with repeated use and abuse.

For some things (especially concrete things like animals or toothpaste products), it is easy to find a useful reference class, while for other things it is difficult to find which possible reference class, if any, is useful. Some things just do not fit nicely enough into an existing reference class to make the method useful - they are unclassreferencable, and it is unlikely to be worth the effort attempting to use the method, when you could just look at more specific details instead. ("Unclassreferencable" suggests a dichotomy, but it's more of... (read more)

I'd say that this is clashing with the sense that more should be possible in the world, and it has the problem that the reference classes are based on specific results. You almost sound like Lord Kelvin.

The reference class of things promising eternal life is huge, but it's also made of stuff that is amazingly irrational, entirely based on narrative, and propped up with the greatest anti-epistemology the world has ever known. Typically there were no moving parts.

The reference class for coming of a new world, to me, includes predictions like talk about the... (read more)

Reference class forecasting might be an OK way to criticise an idea (that is, in situations where you've done something a bunch of times, and you're doing the exact same thing and expect a different outcome despite not having any explanations that say there should be a different outcome), but the idea of using it in all situations is problematic, and it's easy to misapply:

It's basically saying 'the future will be like the past'. Which isn't always true. In cases like cryonics -- cases that depend on new knowledge being created (which is inherently unpredic... (read more)

Any wrongness can be explained as referencing a suboptimal reference class compared to an idealised reference class.

I knew that there was something else that I wanted to ask.

How closely is the Optimism Bias similar to the Dunnin-Krueger Effect?

reference class of beliefs in coming of a new world, be it good or evil, is huge and with consistent 0% success rate.

That's odd. This would imply that you don't believe in evolution of homo sapiens sapiens from previous hominids, or the invention of agriculture... . Heck, read the descriptions of heaven in the New Testament: the description of the ultimate better world (literally heaven!) is a step backward from everyday life in the West for most people.

It seems we have lots of examples of the transformation of the world for better, though I'd say there's not much room for worse than the lowest-happiness lives already in history.

Typo in para 1: "guess which will invariably turned out" => "turn out"

"Many economic and financial decisions depend crucially on their timing. People decide when to invest in a project, when to liquidate assets, or when to stop gambling in a casino. We provide a general result on prospect theory decision makers who are unaware of the time-inconsistency induced by probability weighting. If a market offers a sufficiently rich set of investment strategies, then such naive investors postpone their decisions until forever. We illustrate the drastic consequences of this “never stopping” result, and conclude that probability distortion in combination with naivité leads to unrealistic predictions for a wide range of dynamic setups.""

The whole issue of "singularity" needs a bit of clarification. If this is a physical singularity, i.e. a breakdown of a theory's ability to predict, then this is in the reference class of "theories of society claiming current models have limited future validity", which makes it nearly certain to be true.

If its a mathematical singularity (reaching infinity in finite time), then its reference class is composed nearly solely of erroneous theories.

You can get compromises between the two extremes (such as nuclear chain reactions - massive self feeding increase until a resource is exhausted), but it's important to define what you mean by singularity before assigning it to a reference class.