[EM] Reply to Chris regarding the Approval bad-example

[MIKE OSSIPOFF]

Chris said:

Mike refers to this scenario:
 
> The Approval bad-example is an example of that. I'll give it again here:
>
> Sincere preferences:
>
> 49: C
> 27: A>B
> 24: B>A
>
> A majority _equally strongly_ prefer A and B to C.
>
>
> Actual votes:
>
> The A voters defect, in order to take advantage of the 
> co-operativeness and
> responsibility of the A voters:
>
> 49: C
> 27: A>B
> 24: B
>
 
I agree that *if* the sincere preferences are as Mike specifies then a 
just interventionist mind-reading God
should award the election to A.

[endquote]

Fine. But can Chris say what's wrong with that outcome in other instances?

Chris continued:
 
But a voting method's decisions and philosophical justification should 
be based on  information that is actually
on the ballots, not on some guess or  arbitrary assumption about some 
maybe-existing "information" that isn't.

[endquote]

Why? Why shouldn't a voting system avoid a worst-case, if, by so doing,
it hasn't been shown to act seriously wrongly in other cases?
 
And MMPO & MDDTR don't just bring improvement in the Approval bad-example. They,
in general, get rid of any strategy dilemma regarding whether you should middle-rate
a lesser-evil instead of bottom-rating hir. For instance, consider the 
A 100, B 15, C 0 utility example.

In MCA, there's a question about whether you should middle-rate or bottom-rate B. In
MDDTR and MMPO, that dilemma is completely eliminated.

In those methods, middle rating someone can never help hir against your favorite(s).

Chris continues:

I think a very reasonable tenet is that if, based on the information on 
the ballots, candidate X utterly dominates
candidate Y then we should not elect Y.

[endquote]

Yes, there are many reasonable tenets among the aesthetic criteria.

 Chris continues:

For several reasons (for those who can pooh-pooh this as "merely 
aesthetic"): electing Y gives the supporters
of X a  very strong post-election complaint with no common-sense or 
philosophically cogent answer, X is highly
likely to be higher Social Utility (SU),  Y's victory will have 
compromised legitimacy.

[endquote]

Wait a minute. These candidates in this example are A, B, and C.

How does A lack legitimacy? Among the candidates not majority-defeated, A
has more favoriteness-supporters than any other candidate.

 Chris continues:

The Plurality criterion is one very reasonable criterion that says that 
C  is so much stronger than A that the election
of  A can't be justified. .

[endquote]

There are lots of aesthetic criteria that say things like that, and they all sound
aesthetically reasonable. How great is their practical strategic importance?


Chris continued:

There are other criteria I find reasonable 
that say the same thing:
 
"Strong Minimal Defense": If the number of ballots on which both X is 
voted above bottom and Y isn't is greater than
the total number of ballots on which Y is voted above bottom, then don't 
elect Y.

[endquote]

But can you word that in such a way that it isn't met by Plurality?

What sort of strategic guarantees are protected by the criteria
that you propose in this posting?

Chis continues:

The election of  A is unacceptable because C's domination of  A is 
vastly more impressive than A's pairwise win over
B.  The Plurality criterion plus the three other criteria I define above 
all loudly say "not A".

[endquote]

In other words, it looks bad from those perspectives.

The election of A is justified by its being consistent with FBC, SFC or SFC3,
freedom from dilemma about middle-rating a compromise, and either 
Later-No-Harm or non"failure" in Kevin's MMPO bad-example.  --things that are
guaranteed by MMPO and MDDTR.

Additionally, as I was showing to Jameson, electing A in these methods
isn't really wrong.
 

 
> The A voters defect, in order to take advantage of the 
> co-operativeness and
> responsibility of the A voters:
 
 Chris replies:

The plausibility of  arbitrary claims about the voters' sincere 
preferences and motivations

[endquote]

More a matter of "what if", rather than claims.

Chris continued:

can weighed in the light of the
used election method's incentives. How is it so "co-operative and 
responsible" of the A voters to rank B when doing
so (versus truncating) can only help their favourite?

[endquote]

It's co-operative because it defeats the candidate commonly disliked by A
voters and B voters, in MCA, MDDTR and MMPO.

If neither did that, C would win.

If the A voters refused to, and, instead, the B voters co-operated, then it would
be B would win, by being the defectors.

Chris continues:

And why would the 
B voters be insincerely truncating ("defecting")
when doing so can only harm their favourite?

[endquote]

In MCA that defection could give their favorite the win, if the A voters have
co-operated, in spite of the A voters being more numerous.

In MPPO or MDDTR, the problem doesn't exist. The A voters can co-operate or
defect, and A will still win, having more top ratings. Hardly a controversial
result.

Chris continues:

Given the incentives of the MDD,TR method that Mike is advocating, it is 
only reasonable to assume that the truncators
are all sincere

[endquote]

Wait a minute: I'm not saying that B truncation is a problem in MDDTR or MMPO. In fact,
my point is that it is _not_.  But co-operaton/defection is indeed a problem in MCA.
Hency my advocacy of MDDTR and MMPO.

  		 	   		  
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