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Rationalism is an ideal, yet those who label themselves as such do not realize their base of knowledge could be wrong.

They lack an understanding of epistemology and it gives them confidence. I wonder if these 'rationalists' are all under age 40, they havent seen themselves fooled yet.

It's every bit a proto religion. And frankly quite reminiscent of my childhood faith.

It has a priesthood that speaks for god (quantum). It has ideals passed down from on high. It has presuppositions about how the universe functions which must not be questioned. And it's filled with people happy that they are the chosen ones and they feel sorry for everyone that isn't enlightened like they are.

In the OPs article, I had to chuckle a little when they started the whole thing off by mentioning how other Rationalists recognized them as a physicist (they aren't). Then they proceeded to talk about "quantum cloning theory".

Therein is the problem. A bunch of people vociferously speaking outside their expertise confidently and being taken seriously by others.

This seems like exactly the opposite of everything I've read from the rationalists. They even called their website "less wrong" to call attention to knowing that they are probably still wrong about things, rather than right about everything. A lot of their early stuff is about cognitive biases. They have written a lot about "noticing confusion" when their foundational beliefs turn out to be wrong. There's even an essay about what it would feel like to be wrong about something as fundamental as 2+2=4.

Do you have specific examples in mind? (And not to put too fine a point on it, do you think there's a chance that you might be wrong about this assertion? You've expressed it very confidently...)

They're wrong about how to be wrong, because they think they can calculate around it. Calling yourself "Bayesian" and calling your beliefs "priors" is so irresponsible it erases all of that; it means you don't take responsibility if you have silly beliefs, because you don't even think you hold them.

I am really not sure where you get any of these ideas. For each of your critiques, there are not only discussions, but taxonomies of compendiums of discussions about the topics at hand on LessWrong, which can easily be found by Googling any keyword or phrase in your comment.

On "considering what should be the baseline assumption":

https://www.lesswrong.com/w/epistemology

https://www.lesswrong.com/w/priors, particularly https://www.lesswrong.com/posts/hNqte2p48nqKux3wS/trapped-pr...

On the idea that "rationalists think that they can just apply rationality infinitely to everything":

https://www.lesswrong.com/w/bounded-rationality

On the critique that rationalists are blind to the fact that "reason isn't the only thing that's important", generously reworded as "reason has to be grounded in a set of human values", some of the most philosophically coherent stuff I see on the internet is from LW:

https://www.lesswrong.com/w/metaethics-sequence

https://www.lesswrong.com/w/human-values

On "systematically plan to validate":

https://www.lesswrong.com/w/rationality-verification

https://www.lesswrong.com/w/making-beliefs-pay-rent

On "what could hold true for one moment could easily shift":

https://www.lesswrong.com/w/black-swans

https://www.lesswrong.com/w/distributional-shifts

https://www.lesswrong.com/w/forecasting-and-prediction

Looking it the first link https://www.lesswrong.com/w/epistemology - it has frankly a comically shallow description of the topic, same with https://www.lesswrong.com/w/priors. In just about every discussion, I may be just the entirely wrong audience, but to me they don't even begin to address the narrow topic of choice, let alone form competent building blocks to form any solid world view.

I support anyone trying to form rational pictures of the universe and humanity. If the LessWrong community approach seems to make sense and is enriching to your understanding of the world then I am happy for you. But, every time I try to take a serious delve into LessWrong, and I have done it multiple times over the years, it sets off my cult/scam alerts.