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From: cik@l.cc.purdue.edu (Herman Rubin)
Newsgroups: news.groups
Subject: Re: ``Paradoxes'' are wishy-washy when applied to approval voting
Summary: Voting paradoxes are unavoidable.
Message-ID: <1738@l.cc.purdue.edu>
Date: 23 Nov 89 14:51:24 GMT
References: <4037@sbcs.sunysb.edu>
Distribution: usa
Organization: Purdue University Statistics Department
Lines: 44

In article <4037@sbcs.sunysb.edu>, brnstnd@stealth.acf.nyu.edu (Dan Bernstein) writes:
> The usual, rigorous, mathematical proofs of voting paradoxes do not
> apply to approval voting, as in Alien's MAUVE and WEIP systems discussed
> in news.groups.

			.......................

> This doesn't apply to approval voting because the vote for name A
> is independent of the vote for name B. In the example above, rec.aquaria
> will get its 500 votes whether or not rec.aquarium is present. Approval
> voting just adds up the votes for each name; and so rec.aquaria wins.
> This independence is crucial to the theoretical and practical success
> of approval voting.
> 
> Herman Rubin considers this independence between names to be impossible,
> for reasons of psychological ``rationality.'' He argues, in the case of
> newsgroup creation, that someone who prefers sci.aquaria to rec.aquaria
> will vote against rec.aquaria, so as to improve sci.aquaria's chance of
> winning---even if rec.aquaria would be acceptable.

Suppose that those in favor of sci.aquaria think that rec.aquaria is only
marginally better than the previously existing alt.aquaria.  This may
very well be the case (I do not know, and I did not participate in the
vote).  It may even be that sci.aquaria would defeat rec.aquaria almost
unanimously among those who want an aquaria group in the regular groups,
and still lose in approval voting.  It only takes one person who wants
rec.aquaria and not sci.aquaria to get this result.

| But no sensible voter would adopt that strategy. After all, if everyone
| did, then both names would fail---and hence it's not the right strategy
| for someone who wants the group to pass. (Such reasoning---assuming that
| there is an optimal strategy, then assuming that everyone else will find
| it, and finally figuring out what it is---is called ``superrational'' by
| Hofstadter. I don't know if he originated the term.)
 
There are times that a superrational strategy can be justified, but I see no
evidence of it in this case.  My previous paragraph shows that this can be
false.


-- 
Herman Rubin, Dept. of Statistics, Purdue Univ., West Lafayette IN47907
Phone: (317)494-6054
hrubin@l.cc.purdue.edu (Internet, bitnet, UUCP)