Talk:Arrow's impossibility theorem: Difference between revisions
Talk:Arrow's impossibility theorem (view source)
Revision as of 00:27, 10 January 2020
, 4 years ago→EPOV on Arrow and cardinal methods
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Dr. Edmonds (talk | contribs) |
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I expand on these points quite a bit in my email. The full message is archived here: "'''[http://lists.electorama.com/pipermail/election-methods-electorama.com/2020-January/002403.html (EM) Arrow's theorem and cardinal voting systems]'''". I'm eager to read what the membership there thinks on this topic, since that group of people has frequently been successful at changing my mind on a particular topic. I'm also eager to read your response to my message (privately or publicly, via whatever mode of communication you prefer). -- [[User:RobLa|RobLa]] ([[User talk:RobLa|talk]]) 23:47, 9 January 2020 (UTC)
: I would not say you are wrong but there are a few things you are missing. Most importantly is that Gibbard-Satterthwaite theorem is not Arrows theorem. Yes they are related but Gibbard-Satterthwaite is way more general. Arrows theorem talks about the specific criteria which will be failed. The importance of arrows theorem is that it shows that Ordinal systems must have one of the bad issues. Gibbard-Satterthwaite shows that all systems has some issue with strategy but it may not be a particularly bad issue. I realize that it is tempting to say all systems have issues but I think that is a misguided narrative because it implies that all issues are equally bad. All systems have trade-offs and some of the trade-offs are not worth it. The question is about what is the optimal balance. Most use Arrow as a way to say that Ordinal systems will not be monotonic and monotonicity is too important to trade away when cardinal systems exist. The narrative "Who cares if IRV is nonmonotonic? Arrows theorem shows that all systems will be nonmonotonic" is pushed by FairVote. It is wrong. Monotonicity is a core concept to fair voting. --[[User:Dr. Edmonds|Dr. Edmonds]] ([[User talk:Dr. Edmonds|talk]]) 00:26, 10 January 2020 (UTC)
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