I have had similar thougths too, and hereby announce slight willingness to cooperate.
The main deviation from the mockup seems to be that I think that prouse is going to be dead weight to computers. And anything that requires participants first to to read and figure out lots of prose will also miss out on the computability. Thus I think that the free prose should be reduced nearly to the level of simple tags. Paragraphs surely won't do. The units should be language independent but be rendered (or approximated) to participants in their language. Some "basic" relationships such as belief, impication, conjucation are a given but I think it would be vital for flexibility to add new notions. Ideally the basic relationsships would not be "built in" but could in principle be inputted from scratch by users. It's a little "make a big database and hope for the best". The critical part would make it semi legible particable to someone not versed in it.
The core of the notions would be various rules of inference. For example the notion of modus ponens can be summed up as a rule regarding truths and implications. A rule of the same level would be appeal to authority. You could choose which notion princples you belief in (and they would be processed as beliefs as good as any). If many people do this (and set their beliefs as public) you could have distribution on why people belief what they belief. You could also point new users to take into consideration arguments that have gone throught for previous users that have believed like them (or maybe only those belief transitions that people have found positive). If an argument doesn't go throught with you you could point out why, which would allow further discussion. Actually one argument could branch into several depending on who has issue with which side and counterpoint of it.
The a big part of the cognitive work when using the system would be to express the thought with such clarity it can be explictly marked up. However it could be controlled by what kind of scope you allow for atomic notions. Say one says he believes in some "-ism". That could be accepted as a simple belief->"-ism". Then if big conflicts arise because of the ambiguity people could offer more elaborate explicit expressions of it. Some fo the "definitions" could be rejected or just fall out of fashion or focus. Explicications could be a move in the game.
By taking a record of what notion princples people believe in you could play a game where you extract a set of principles foreign to your own and try to apply them to get to a particular conclusion. This could be done without direct live interaction. Another level of game goal could be that when a user of with that set of princples logs in they could entertain the argument and the system could check whether the argument is successful (with the user being the judge). One game could be that a persons asks for checking their beliefs for possibilties to derive "a" and "not a".
The tricky part is how to make the notion princples easy enough to express comprehensively. Or coming up with the core or seed notion princples that meaningfull activity can be carried out.
The a big part of the cognitive work when using the system would be to express the thought with such clarity it can be explictly marked up.
I think that that's too big an obstacle. And for that reason, I think it needs to be more lightweight. You could get a lot of the benefits of structure with it being lightweight, without pushing people away from using it.
It would be cool if online discussions allowed you to 1) declare your claims, 2) declare how your claims depend on each other (ie. make a dependency tree), 3) discuss the claims, and 4) update the status of the claim by saying whether or not you agree with it, and using something like the text shorthand for uncertainty to say how confident you are in your agreement/disagreement.
I think that mapping out these things visually would allow for more productive conversation. And it would also allow newcomers to the discussion to quickly and easily get up to date, rather than having to sift through tons of comments. On this note, there should also probably be something like an answer wiki for each claim to summarize the arguments and say what the consensus is.
I get the feeling that it should be flexible though. That probably means that it should be accompanied by the normal commenting system. Sometimes you don't actually know what your claims are, but need to "talk it out" in order to figure out what they are. Sometimes you don't really know how they depend on each other. And sometimes you have something tangential to say (on that note, there should probably be an area for tangential comments, or at least a way to flag them as tangential).
As far who would be interested in this, obviously this Less Wrong community would be interested, and I think that there are definitely some other online communities that would (Hacker News, some subreddits...).
Also, this may be speculating, but I would hope that it would develop a reputation for the most effective way to have a productive discussion. So much so that people would start saying, "go outline your argument on [name]". Maybe there'd even be pressure for politicians to do this. If so, then I think this could put pressure on society to be more rational.
What do you guys think?
EDIT: If anyone is actually interested in building this, you definitely have my permission (don't worry about "stealing the idea"). I want to build it, but 1) I don't think I'm a good enough programmer yet, and 2) I'm busy with my startup.
EDIT: Another idea: if you think that a statement commits an established fallacy, then you should be able to flag it (like this). And if enough other people agree, then the statement is underlined or highlighted or something. The advantage to this is that it makes the discussion less "bulky". A simple version of this would be flagging things as less than DH6. But there are obviously a bunch of other things worth flagging that Eliezer has talked about in the sequences that are pretty non-controversial.
EDIT: Here is a rough mockup of how it would look. Notes:
- The claims should show how many votes of agreement/disagreement they got. Probably using text shorthand for uncertainty.
- The claims should be colored green if there is a lot of agreement, and red if there is a lot of disagreement.
- See edit above. Commenting in the discussion should be like this. And you should be able to flag statements as fallacious in a similar way. If there is enough agreement about the flag, the statement should be underlined in red or something.