itaibn0 comments on Many Weak Arguments vs. One Relatively Strong Argument - Less Wrong

20 Post author: JonahSinick 04 June 2013 03:32AM

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Comment author: Eliezer_Yudkowsky 04 June 2013 06:18:46PM 11 points [-]

Penrose is a worrisome case to bring as an example, since he is in fact wrong, and therefore you're giving an example where your reasoning leads to the wrong conclusion. If you can't easily find examples where your reasoning led you to a new correct conclusion instead of new sympathy toward a wrong conclusion, this is worrisome. In general, I tend to flag recounts of epistemological innovations which lead to new sympathy toward a wrong conclusion, as though the one were displaying compassion for a previously hated enemy, for in epistemology this is not virtue.

The Penrose example worries me for other reasons as well, namely it seems like it would be possible to generate hordes and hordes of weak arguments against Penrose; so it's as if because the argument against Penrose is strong, you aren't bothering to try to generate weak arguments; reading this feels like you now prefer weak arguments to strong arguments and don't try to find the many weak arguments once you see a strong argument, which is not good Bayesianism.

You also claim there's a strong argument for Penrose, namely his authority (? wasn't this the kind of reasoning you were arguing against trusting?) but either we have very different domain models here, or you're not using the Bayesian definition of strong evidence as "an argument you would be very unlikely to observe, in a world where the theory is false". What do you think is the probability of at least one famous physicist writing a widely panned book about the noncomputability of human consciousness, in a world where consciousness is computable? I should not call it very low, and that means that the pure argument from authority, if you don't believe the actual specifics of that argument, is Bayesian evidence with a low likelihood ratio or as it would be commonly termed a 'weak argument'.

Comment author: itaibn0 05 June 2013 10:45:07AM 9 points [-]

Penrose is a worrisome case to bring as an example, since he is in fact wrong, and therefore you're giving an example where your reasoning leads to the wrong conclusion.

JonahSinick is not saying that Penrose is right, only that based on his heuristic he adjusted the probability of that upwards. To judge this wrong, it's not enough to know that Penrose is wrong, you must also know the probability estimates JonahSinick gave before and after. To give an absurd example, if JonahSinick used to believe the probability was 10^(-15), he would be wise to adjust upwards.

By the way, this isn't the first time I see you use the meta-heuristic that when a heuristic adds support to a wrong conclusion it should be taken less seriously. While it is valid to some extent, I think you are overusing it.