LessWrong is online forum/community that was founded with the purpose of perfecting the art of human[2] rationality.

While truthfulness is a property of beliefs, rationality is a property of reasoning processes. Our definition[3] of rationality is that a more rational reasoning process tends to arrive at true beliefs and good decisions more often than a less rational process. For example, a reasoning process that responds to evidence is more likely to believe true things than one that just goes with what's convenient to believe. An aspiring rationalist[4] is someone who aspires to improve their own reasoning process to arrive at truth more often.

...a rationalist isn't just somebody who respects the Truth...All too many people respect the Truth. A rationalist is somebody who respects the processes of finding truth. – Rationality: Appreciating Cognitive Algorithms

[Aspiring] rationalists should win [at life, their goals, etc]. You know a rationalist because they're sitting atop a pile of utility. – Rationality is systematized winning

The Art [of rationality] must have a purpose other than itself, or it collapses into infinite recursion. - the 11th virtue of rationality

On LessWrong we attempt (though don't always succeed) to apply the rationality lessons we've accumulated to any topic that interests us, and especially topics that seem important, like how to make the world a better place. We don't just care about truth in the abstract, but care about having true beliefs about things we care about so that we can make better and more successful decisions.

Right now, AI seems like one of the most (or the most) important topics for humanity. It involves many tricky questions, high stakes, and uncertainty in an unprecedented situation. On LessWrong, many users are attempting to apply their best thinking to ensure that the advent of increasingly powerful AI goes well for humanity.[5]

Is LessWrong for you?

LessWrong is a good place for someone who:

values curiosity, learning, self-improvement, figuring out what's actually true (rather than just what you want to be true or just winning arguments)

will change their mind or admit they're wrong in response to compelling evidence or argument

wants to work collaboratively with others to figure out what's true

likes acknowledging and quantifying uncertainty and applying lessons from probability, statistics, and decision theory to your reasoning

is nerdy and interested in all questions of how the world works and who is not afraid to reach weird conclusions if the arguments seem valid

likes to be pedantic and precise, and likes to bet on their beliefs

doesn't mind reading a lot

If many of these apply to you, then LessWrong might be the place for you.

LessWrong has been getting more attention (e.g. we get linked in major news articles somewhat regularly these days), and so have many more people showing up on the site. We, the site moderators, don't take for granted that what makes our community special won't stay that way without intentional effort, so we are putting more effort into tending to our well-kept garden.

If you're on board with our program and will help make our community more successful at its goals, then welcome!

Okay, what are some examples of what makes LessWrong different?

I just had a crazy experience. I think I saw someone on the internet have a productive conversation.

I was browsing this website (lesswrong.com, from the guy who wrote that Harry Potter fanfiction I've been into), and two people were arguing back and forth about economics, and after like 6 back and forths one of them just said "Ok, you've convinced me, I've changed my mind".

Has this ever happened on the internet before?

– paraphrased and translated chatlog (from german) by Habryka to a friend of his, circa 2013-2014

The LessWrong community shares a culture that encodes a bunch of built up beliefs, opinions, concepts, and values about how to reason better. These give LessWrong a pretty distinct style from the rest of Internet.

Some of the features that set LessWrong apart:

We applaud you for saying "oops"

We treat beliefs as being about shaping your anticipations of what you'll observe[6]

The goal of our conversations is to figure out what's true, not to win arguments

we try to focus on what would change our minds

it's common for us to acknowledge when someone we are debating has made a convincing point, or has even outright convinced us entirely

We are very Bayesian

Rather than treating belief as binary, we use probabilistic credences to express our certainty/uncertainty. Rather than say that is "extremely unlikely", we'd say "I think there's a 1% chance or lower of it happening".

We are interested in Bayesian evidence for or against a hypothesis, i.e. observations we are more or less likely to make if the hypothesis is true vs not.

We avoid certain behaviors that seem to make conversation worse on the rest of the Internet.

examples here

And strive for other things that make conversations better.

these are not official LessWrong site guidelines, but suggestive of the culture around here: Basics of Rationalist Discourse and Elements of Rationalist Discourse

(http://www.autoadmit.com/thread.php?thread_id=5893530&forum_id=2锞兾告触锟界锟絇HPSESSID=962c303388ae8b5678383d002493727e#50070500)