Vladimir_Nesov comments on Making Beliefs Pay Rent (in Anticipated Experiences) - Less Wrong

110 Post author: Eliezer_Yudkowsky 28 July 2007 10:59PM

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Comment author: Vladimir_Nesov 09 August 2010 08:05:55PM 1 point [-]

It does contradict that assertion, but not at first approximation, and not in the sense you took the issue with. You have to be very careful if a belief doesn't translate into anticipated experience. Beliefs about historical facts that don't translate into anticipated experience (or don't follow from past experience, that is observations) are usually invalid.

Comment author: Dpar 09 August 2010 08:17:30PM 0 points [-]

You seem to place a good deal of value on the concept of anticipated experience, but you give it a definition that's so broad that the overwhelming majority of beliefs will meet the criteria. If the belief in ghosts for instance can lead to the anticipated experience of reading about them in a book, what validity does the notion have as a means of evaluating beliefs?

Comment author: Vladimir_Nesov 09 August 2010 08:25:58PM *  1 point [-]

When a belief (hypothesis) is about reality, it responds to new evidence, or arguments about previously known evidence. It's reasonable to expect that as a result, some beliefs will turn out incorrect, and some certainly correct. Either way it's not a problem: you do learn things about the world as a result, whatever the conclusion. You learn that there are no ghosts, but there are rainbows.

The problem are the beliefs that purport to be speaking about reality, but really don't, and so you become deceived by them. Not being connected to reality through anticipated experience, they take your attention where there is no use for them, influence your decisions for no good reason, and protect themselves by ignoring any knowledge about the world you obtain.

It is a great heuristic to treat any beliefs that don't translate into anticipated experience with utmost suspicion, or even to run away from them in horror.

Comment author: Dpar 09 August 2010 08:47:13PM 0 points [-]

How would you learn that there are no ghosts? You form the belief "there are ghosts" which leads to the anticipated experience (by your definition of such) that "I will read about ghosts in a book", you go and read about ghosts in a book. Criteria met, belief validated. Same goes for UFOs, psychics, astrology etc. What value does the concept of anticipated experience have if it fails to filter out even the most common fallacious beliefs?

Comment author: Vladimir_Nesov 09 August 2010 09:06:32PM 2 points [-]

That there are books about ghosts is evidence for ghosts existing (but also for lots of other things). There are also arguments against this hypothesis, both a priori and observational. A good model/theory also explains why you'd read about ghosts even though there is no such thing.

Comment author: Dpar 09 August 2010 09:25:01PM 0 points [-]

You're not addressing my core point though. If the criteria of anticipated experience as you define it is as likely to be satisfied by fallacious beliefs as it is by valid ones, what purpose does it serve?

Comment author: Vladimir_Nesov 09 August 2010 09:28:00PM *  1 point [-]

I addressed that question in this comment; if something is unclear, ask away. The difference is between a belief that is incorrect, and a belief that is not even wrong.

Comment author: Dpar 09 August 2010 09:42:10PM 1 point [-]

Alright, I think I see what you're getting it, but I still can't help but think that your definition of sensory experience is too broad to be really useful. I mean the only type of belief that it seems to filter out is absolute nonsense like "I have a third leg that I can never see or feel", did I get that about right?

Comment author: Vladimir_Nesov 09 August 2010 09:49:11PM *  1 point [-]

I mean the only type of belief that it seems to filter out is absolute nonsense like "I have a third leg that I can never see or feel", did I get that about right?

Yes. It happens all the time. It's one way nonsense protects itself, to persist for a long time in minds of individual people and cultures.

(More generally, see anti-epistemology.)

Comment author: Dpar 09 August 2010 09:55:46PM 1 point [-]

So essentially what you and Eliezer are referring to as "anticipated experience" is just basic falsifiability then?

Comment author: jimrandomh 09 August 2010 10:09:28PM 1 point [-]

Falsifiability can be quantified, in bits. If the only test you have for whether something's true or not is something lame like whether it appears in stories or not, then you have a tiny amount of falsifiability. If there is a large supply of experiments you can do, each of which provides good evidence, then it has lots of falsifiability.

(This really deserves to be formalized, in terms of something along the lines of expected bits of net evidence, but I'm not sure how to do so, exactly. Expected bits of evidence does not work, because of scenarios where there is a small chance of lots of evidence being available, but a large chance of no evidence being available.)

Comment author: SilasBarta 09 August 2010 10:20:53PM *  3 points [-]

Just a note about terminology: "expected bits of evidence" also goes by the name of entropy, and is a good thing to maximize in designing an experiment. (My previous comment on the issue.)

And if I understand you correctly, you're saying that the problem with entropy as a measure of falsifiability, is that someone can come up with a crank theory that gives the same predictions in every single case, except one that is near impossible to observe, but which, if it happened, would completely vindicate them?

If so, the problem with such theories is that they have to provide a lot of bits to specify that improbable event, which would be penalized under the MML formalism because it lengthens the hypothesis significantly. That may be want you want to work into a measure of falsifiability.

But then, at that point, I'm not sure if you're measuring falsifiability per se, or just general "epistemic goodness". It's okay to have those characteristics you want as a separate desideratum from falsifiability.

Comment author: Dpar 09 August 2010 11:09:43PM 1 point [-]

Isn't it an essential criteria of falsifiability to be able to design an experiment that can DEFINITIVELY prove the theory false?