Rob-- You wrote:
I agree with Warren that a system that doesn't break down in the face of full rankings is highly desirable, for many of the reasons that he cites. I reply: I assume you're implying that MDDA breaks down in the fact of full rankings. If everyone but me were going to vote full rankings in MDDA, I'd vote only for Nader, and so Nader would automatically win the approval count. Unless Nader has a majority defeat and someone else doesn't, Nader wins. The full-ranking electorate have given me the power to choose the president. For everyone to rank fully in MDDA would be unstable, because any one voter could improve his/her expectation by bullet-voting, assuming that we don't have information about who is likely to be majority-disqualified. Approval, too, would "break down" if everyone voted for all the candidates. I recommend against doing so. As Kevin pointed out, it makes no sense whatsoever to rank all the candidates in MDDA. Don't rank your last choice. Then you're voting everyone over him/her in Approval. You're casting an Approval vote that says who is the worst candidate. As Kevin said, if everyone did that, a tie would be as unlikely as it is now in ordinary Plurality. So let's lay to rest this notion of MDDA having a problem with everyone ranking all the candidates. You continued: I think his argument could be reworded slightly to be less controversial. It's not that there's a universal or near-universal desire to provide full rankings. I reply: That's for sure. I've just voted in an Internet presidential poll with 15 candidates. Ranking all of them was a bit of work. Even more so in the EM presidential poll with 46 candidates. Few people will want to bother ranking all the candidates when there are more than a few. You continued: A system that violates later-no-harm therefore has a serious political liability in that regard. I reply: That's a strong statement, and it requires justification. Who says that rightness requires that people should have no incentive to not rank everyone? You continued: My personal belief is that satisfying later-no-harm (or at least minimizing violation to rare instances) is highly desirable. I reply: All criteria are desirable. It's a question of choosing which ones one considers most important, especially when it isn't possible to comply with all of them. To you it's very important to encourage people to rank all the candidates, with no incentive to do otherwise. To me it's more important to assure people that there's absolutely no reason to bury their favorite. I don't say that your standards are wrong. But remember that others' standards aren't wrong because they differ from yours. There aren't right or wrong standards. What's wrong is the notion that there are. And, by the way, MDDA's SFC compliance gives some protection against LNH failures, for people who rank the candidates they don't like. Its premise conditions aren't at all implausible. But you're right that it would usually be a better idea to not rank the ones you don't like. Sure, I could help to give Bush a majority defeat from Kerry, but why should I do that when I can just vote an Approval difference against both of them by ranking neither. But MDDA's SFC guarantee means that it doesn't do so much harm when the giveaway progressives insist on ranking Kerry. They're failing to vote an Approval difference between Kerry and their favorite, but they're still contributing toward a possible majorilty defeat for Kerry. If you think that's unrealistic that a majority would rank Nader over Kerry, consider that Nader is usually the voted CW in nearly all presidential rank-ballotingl polls. Sure, Condorcet(wv) encourages ranking all the candidates, unless offensive order-reversal is expected. But I found it a bit yucky to rank candidates I don't like. I have no objection whatsoever to a method in which it's strategically better to not rank disliked candidates. You continued: I personally believe that getting people to think deeply about compromises is how we get to a more civil state in politics. If people can be jostled out of their comfort zone and consider the relative merits of candidates who they might at first blush consider "evil", then perhaps we'll truly get less evil candidates than the current batch who foment partisan rancor. I reply: I disagree. Why is it better if people consider the relative merits of Kerry and Bush, or McKain and Hillary Clinton, etc.? To talk of their relative merits implies that there is a significant merit difference. Why waste time, debasing oneself with concern about the merit-difference between meritless candidates? That won't give us less evil candidates, but if we continue trying to find how one is better than another, then it tends to perpetuate their undeserved success. Discard the undeserving candidates. In Condorcet(wv), if you don't expect offensive order-reversal, go ahead and strategically rank them in reverse order of winnability, if you can hold your nose tight enough. That will decrease the chance that one will win. Blake and others have complained about that incentive and used it to argue for margins over wv. But margins has much bigger strategy problems--major defensive strategy need, to protect majority rule or the CW, as opposed to relatively minor strategy incentive. You continued: Here's a related set of questions I've been meaning to ask: 1. Are the Later No Harm (LNH) criterion and the Sincere Favorite Criterion (SFC) mutually incompatible? I reply: SFC stands for Strategy-Free Criterion. Doesn't MMPO meet both of those criteria? You continued: 2. Are LNH and the Favorite Betrayal Criterion (FBC) mutually incompatible? I reply: Doesn't MMPO meet both? You continued: 3. Are LNH, SFC and FBC mutually incompatible? I reply: Doesn't MMPO meet all of those? But regrettably, MMPO has a big problem, as Kevin pointed out. Mike Ossipoff _________________________________________________________________ Express yourself instantly with MSN Messenger! Download today - it's FREE! http://messenger.msn.click-url.com/go/onm00200471ave/direct/01/ ---- election-methods mailing list - see http://electorama.com/em for list info