[EM] Condorcet Criterion for plurality.

[MIKE OSSIPOFF]

Markus said:

>you wrote (13 Dec 2000):
> > My point was not that IIAC is no good because Plurality
> > meets it. My point was that IIAC means that Approval, and
> > even Plurality, are better than IRV, for all those people
> > who bring up Arrow's criteria.
>
>The intention of IIAC is to guarantee that the result of
>the elections cannot be manipulated by running additional
>candidates who change the result of the elections without
>being elected. But you define IIAC is such a manner that
>even plurality --which is highly vulnerable to this strategy--
>meets this criterion. Therefore your definition of IIAC has
>nothing to do with the original intention of this criterion.
>Therefore --and this is what Blake is saying-- you have to
>present an additional justification for your definition of
>IIAC. And in so far as you are unwilling or unable to
>justify your definition of IIAC, the usefulness of your
>"universally accepted" concept is questionable.

What's questionable is how "my" universally accepted concept
that Plurality doesn't collect & use rankings somehow depends on
what the correct definition of of IIAC is, or whether I can
justify IIAC.

I don't know what the correct definiton of IIAC is. All I'm saying
is that my definition of it is the only complete definition of it
that has ever been posted here.

Justify IIAC? I've repeatedly said that IIAC doesn't mean anything
to me. Its importance derives entirely from the fact that lots
of people, including IRVies, keep bringing it up. That's great when
they do that, since the only complete IIAC definition that I've
heard of says that Approval is better than IRV and that even
Plurality is better than IRV. Obviously there are many reasons
why those methods are better than IRV, but when the IRVies' own
citation of Arrow counts against IRV, that makes IIAC useful.
_That's_ my justification of IIAC.

Maybe Arrow's own definition of IIAC is different from mine. Maybe
it's justified in some way that mine isn't. Fine. Arrow, as I said,
is a mystery man whose criteria are shrouded in myth & legend.
Apparently it's going to stay that way on this list. I don't care.

>
>You wrote (13 Dec 2000):
> > Layton asked for uniformity, and I have to agree with
> > him that Markus's system (if it uses different rules for
> > different methods) is quite useless for compring voting
> > systems, because uniformity of criterion application rules
> > is necessary for comparing methods by criteria.
>
>If you had read Craig Layton's mails more carefully, you
>would have observed that he wrote (13 Dec 2000): "It doesn't
>make sense to define systems with reference to themselves,
>which is what MIKE is attempting to do, because this makes
>it impossible for any meaningful kind of comparison between
>systems."

Yes, and I replied to that by asking you what I defined in terms
of itself. You didn't answer the question, because you knew
that you were just barking again.

But Markus, you're all confused, because I was referring to
something else that Layton said, to the effect that uniformity
is necessary in order to meaningfully compare methods. A particularly
bizarre lack of uniformity is if you would use a different special
rule for applying criteria to each of various different methods.
Then, it's no longer the same criterion that you're applying to the
methods, and so no meaningful comparison is possible by your
system. But then I must admit that you've never really told us
what your system is.

But I couldn't care less if you ever define your system for
applying criteria. I asked if you wanted to define it, and you
don't want to, because you don't know how your journal authors
define it. And, though you don't really know what their system is,
you still want to advocate it and declare your loyalty to it. Fine.

Mike Ossipoff

_____________________________________________________________________________________
Get more from the Web.  FREE MSN Explorer download : http://explorer.msn.com