On Feb 9, 2012, at 9:02 PM, Kevin Venzke wrote:
Hi Robert,
De : robert bristow-johnson <[email protected]>
À : [email protected]
Envoyé le : Jeudi 9 février 2012 10h07
Objet : Re: [EM] [CES #4445] Re: Looking at Condorcet
On 2/8/12 1:25 PM, Juho Laatu wrote:
> On 8.2.2012, at 7.33, robert bristow-johnson wrote:
>
> ...
>> if it's not the majority that rule, what's the alternative?
> I'm not aware of any good alternatives to majority rule in
competitive two-candidate elections (with some extra assumptions
that rule out random ballot etc.).
>
> Juho
thank you Juho, for stipulating to the obvious. i will confess that
i am astonished at the resistance displayed here at the EM list to
this obvious fact.
Nobody on EM said anything contrary to Juho's statement. I agree
with Juho. And Bryan said something similar at the end of his post.
With two candidates, most of us agree that you have to use majority
rule. That doesn't mean it gives perfect answers according to some
ideal. If your ideal is maximum utility, then it's pretty clear
majority rule isn't always giving the correct answer. Not because
the ballots make it clear that this is happening, but because almost
any model of voter preferences will lead to this conclusion. It
would be frankly bizarre, if "fairness" and utility always gave the
same answers.
Actually, a majority is not needed here, but is close enough that we
almost never complain. For an excuse for making trouble I offer:
40 A
41 B
8 A,B legal to vote for more than one in Condorcet.
8 spoiled ballots - can happen even here.
(Your idea of all the utilities being 0 or 1 can't even be made to
work as a model, I don't think, unless voters really only have two
stances toward candidates. Because what happens when you introduce a
third candidate that some people like even better? Utilities don't
change based on who else is in the race, they are supposed to
represent in absolute terms the benefit from a candidate being
elected.)
Utilities do not change? I buy that they do - given that A or B offer
no special value and that neither is worth voting for, getting C in
the race can matter if C is known as willing and able to be useful.
When you try to make an argument for Condorcet and 3+ candidate
scenarios, based on the inevitability of using majority rule with
two candidates, you will fail to convince an advocate of utility,
because an advocate of utility probably doesn't think the method
options are as limited anymore, once you have 3+ candidates. The
majority rule procedure with two candidates may be necessary (Clay
may even disagree with that though), but that doesn't mean it was
always doing the right thing.
Those of us that dislike runoffs might argue against demanding
majority in what follows :
40 A
30 B
15 C>B>A
I count 45B>40A, 30B>15C, 40A>15C - with B winning if we do not
demand majority
Is this clear enough? I understand you want to make a fairness
argument in favor of majority rule with two candidates, and then
build off of that. But a utility advocate may reject fairness and
prefer utility, even without offering a different method that could
be used with two candidates. (He may perceive that there is no
utility improvement to be had by doing something else.) So even if
you attack Range as silly in the two-candidate case, you're not
making the point that fairness is paramount over utility.
Seems to me the voters saw utility - but there is nothing here giving
it a measurable value because there is nothing to measure it with
other than the vote counts (but it is the vote counts that show how
much they saw backing the value they voted for).
I'd note also that utility goes far beyond the question of whether
Range is a workable method. A utility advocate is free to leave
Range in the trash-bin while seeking to maximize utility under other
methods that you might recognize as less prone to exaggeration
strategies.
And from your last mail to me:
>> It could be true if it so happens that nobody wants to vote
truthfully under
>> Condorcet methods, while Approval in practice never has any bad
outcomes, etc.
>
>it could be true that hundreds of people who have testified to such
have actually been abducted by extraterrestrial aliens who poked
needles into them
>and did experiments on human subjects. but it's an extraordinary
claim that requires extraordinary evidence.
Yes, you're right. However, the important point here is just that it
could be true. "More Condorcet than Condorcet" isn't inherently
nonsense. You just have to read it as "better sincere Condorcet
efficiency than under Condorcet methods." Such a thing is possible.
Kevin
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