I don't think there's a single defining point of difference, but I tend to think of it as the difference between the traditional social standard of having beliefs you can defend and the stricter individual standard of trying to believe as accurately as possible.
The How to Have a Rational Discussion flowchart is a great example of the former: the question addressed there is whether you are playing by the rules of the game. If you are playing by the rules and can defend your beliefs, great, you're OK! This is how we are built to reason.
X-rationality emphasizes having accurate beliefs over having defensible beliefs. If you fail to achieve a correct answer, it is futile to protest that you acted with propriety. Instead of asking "does this evidence allow me to keep my belief or oblige me to give it up?", it asks "what is the correct level of confidence for me to have in this idea given this new evidence?"
Eliezer uses "Traditional Rationality" to mean something like "Rationality, as practised by scientists everywhere, especially the ones who read Feynman and Popper". It refers to the rules that scientists follow.
A surely incomplete list of deficiencies:
In some ways, Eliezer is too hard on Traditional Rationalists (TRists). In the "wild and reckless youth" essay, which you cite, he focuses on how TR didn't keep him from privileging a hypothesis and wasting years of his life on it.
But TR, as represented by people like Sagan and Feynman, does enjoin you to believe things only on the basis of good evidence. Eliezer makes it sound like you can believe whatever crazy hypothesis you want, as long as it's naturalistic and in-principle-falsifiable, and as long as you don't expect others to be convinced until you deliver good evidence. But there are plenty of TRists who would say that you ought not to be convinced yourself until your evidence is strong.
However, Eliezer still makes a very good point. This injunction doesn't get you very far if you don't know the right way to evaluate evidence as "strong", or if you don't have a systematic method for synthesizing all the different evidences to arrive at your conclusion. This is where TR falls down. It gives you an injunction, but it leaves too much of the details of how to fulfill the injunction up to gut instinct. So, Eliezer will be contributing something very va...
I just started listening to THIS (perhaps 15min of it on my drive to work this morning), and EY has already mentioned a little about traditional rationality vs. where he is now with respect to reading Feynman. I'm not sure if he'll talk more about this, but Luke's page does have as a bullet point of the things covered:
Eliezer’s journey from ‘traditional rationality’ to ‘technical rationality’
so perhaps he'll continue in detail about this. Off hand, all I can specifically remember is that at one point he encountered some who thought that multiple routes...
One relevant attempt at a definition:
I will be using "extreme rationality" or "x-rationality" in the sense of "techniques and theories from Overcoming Bias, Less Wrong, or similar deliberate formal rationality study programs, above and beyond the standard level of rationality possessed by an intelligent science-literate person without formal rationalist training."
In one essay, Eliezer seems to be saying that Traditional Rationality was too concerned with process, whereas it should have been concerned with winning. In other passages, it seems that the missing ingredient in the traditional version was Bayesianism (a la Jaynes). Or sometimes, the missing ingredient seems to be an understanding of biases (a la Kahneman and Tversky).
All of those are problems with traditional rationality, and Elizeer has critiques traditional rationality for all of them. Traditional rationality should have helped Elizeer more than i...
Eliezer uses "Traditional Rationality" to mean something like "Rationality, as practised by scientists everywhere, especially the ones who read Feynman and Popper".
Traditional rationality goes back to Aristotle and is something that both Feynman and Popper rejected. Among other things, traditionality rationality is:
Popper rejected all of the above, so calling his philosophy "traditional rationality" is highly misleading. Bayesianism, on the other hand, is firmly in the tradition of Aristotle.
It refers to the rules that scientists follow
Popperian philosophy is not a set of rules; Popper emphasized that the truth is not manifest and that there is no road to truth.
A surely incomplete list of deficiencies:
The practitioners only use it within some small domain.
Well, no. Popperism has been applied in many domains, including morality (which empiricist, instrumentalist, Bayesianism is pretty much silent about). See, for example, David Deutsch's "Taking Children Seriously". Also see his new book The Beginning of Infinity. As a point of logic, saying that something is used in a small domain is not a criticism that something can't be used outside that domain.
Maybe they even believe that one can only be rational in this domain.
This just betrays a lack of familiarity with Popperism.
Designed to work for groups, not for individuals. Telling someone to use Science to become smart is like telling them to use Capitalism to become rich.
Popperian philosophy is important for individuals because it is about how knowledge is created and everybody creates knowledge. Again, I refer you to Deutsch. Also, since you mentioned capitalism, Popperian philisophy offers explanations for why capitalism is good, and it can do so because economics is another domain in which it applies :)
It doesn't tell you how to create hypotheses,
Lol. That is a criticism of Bayesianism, not Popperism. Bayesianism is about assigning probabilities to hypotheses and not about how to create new hypotheses. In Popperism, we don't just want to create hypotheses, we want to create explanatory knowledge. Talking about hypotheses is just another sign of instrumentalism. Popperism says that explanatory knowledge arises as conjectural solutions to problem situations. Bayesianism says knowledge is induced from data, which, as Popper argued, is impossible (And this is a very hard thing for people to get their head around because the memes of traditional rationality have seeped into all aspects of most people's thinking. Popper really is different).
Imprecise understanding of probability and knowledge (which are the same thing).
It is an utter debasement of knowledge to say it is all probability. In what sense does a probability correspond to an explanation? How can you reduce the content of an explanation to a probability?
Bizarre fetishisation of "falsification".
It has now been pointed out repeatedly in these forums that Popperism is not falsificationism. Bayesians: please pay attention.
Failure to concentrate on the important problems.
Huh? What important problems did Popper and Feynman not concentrate on?
As prase said, you've been confused by the specific term used - the "Traditional Rationality" that EY was talking about isn't the actual human being that was Karl Popper, but the pop-culture version of Popper which has been a major influence on the thinking of most scientifically-literate people of the modern era.
To make an analogy: if someone asked me what "Romeo" and "Juliet" meant in Taylor Swift's song "Love Story", my answer would be quite inaccurate as a description of the play - because the "Romeo" and "Juliet" in the song aren't the two love-besotted idiots in the play, they're the stereotypical young lovers of pop culture.
In several places in the sequences, Eliezer writes condescendingly about "Traditional Rationality". The impression given is that Traditional Rationality was OK in its day, but that today we have better varieties of rationality available.
That is fine, except that it is unclear to me just what the traditional kind of rationality included, and it is also unclear just what it failed to include. In one essay, Eliezer seems to be saying that Traditional Rationality was too concerned with process, whereas it should have been concerned with winning. In other passages, it seems that the missing ingredient in the traditional version was Bayesianism (a la Jaynes). Or sometimes, the missing ingredient seems to be an understanding of biases (a la Kahneman and Tversky).
In this essay, Eliezer laments that being a traditional rationalist was not enough to keep him from devising a Mysterious Answer to a mysterious question. That puzzles me because I would have thought that traditional ideas from Peirce, Popper, and Korzybski would have been sufficient to avoid that error. So apparently I fail to understand either what a Mysterious Answer is or just how weak the traditional form of rationality actually is.
Can anyone help to clarify this? By "Traditional Rationality", does Eliezer mean to designate a particular collection of ideas, or does he use it more loosely to indicate any thinking that is not quite up to his level?