[EM] James--Strategy, part 1

Sat Apr 23 23:03:26 PDT 2005

James--

You said:

All Condorcet methods are at least somewhat
vulnerable to burying

I reply:

James, say there are two gentlemen who sometimes  punch you in the face. One 
of them might  punch you in the face if someone tells him that you said 
something about his mother, unless you tell him that it isn't true.  The 
other will punch you in the face whenever he feels like it, for no 
particular reason. And he feels like it fairly often.

The 2nd one is better than the first one, right? Because the 2nd one isn't 
"vulnerable to false mother-insult reports".

You continue:

		I consider WV methods to be less vulnerable to burying (perhaps mostly
because it allows for much more stable counterstrategy) than margins
methods, on the theory that, at least in Duvergian scenarios (scenarios
with two major contenders)

I reply:

Duverger's law is about how Plurality results in a two party system. So then 
is a Duvergian scenario a scenario with only two winnable contenders as a 
result of Plurality being the method in use?
You seem to be using "Duvergian scenario" to mean any situation with only 
two winnable candidates, regardless of what method is in use. That seems 
like a wrong use of "Duvergian scenario".

You continue:

, supporters of one Duvergian candidate can
routinely truncate before ranking the other Duvergian candidate, making it
so that any beatpaths returning to the sincere CW will include a <50%
link. This counterstrategy should probably stave off the very worst
burying abuses

I reply:

You're right. If there are only two winnable candidates, then the supporters 
of those have no reason to rank a 2nd choice. Offensive order-reversal will 
backfire every time.

You continue:

, but its applications are somewhat limiting/distorting in
that they require widespread truncation.

I reply:

No, given your assumptiont that there are only 2 winnable candidates, 
offensive order-reversal disappears as a problem. "Widespread truncation" is 
the obvious expected way of voting for supporters of the big-two candidates. 
That would be known to every voter.

You continue:

	But anyway, yes, Condorcet methods (including WV) do have a problem that
IRV doesn't have, because they fail LNH

I reply:

Maybe I neglected to tell you that I'm not interested in the question of 
whether, by some way you define "new problem", wv has a new problem. I 
didn't say that before? I meant to tell you that I'm more concerned about 
certain undesirable results that I defined, results that are just as bad 
regardless of what particular mechanism led to them. And, though I didn't 
spell that out before, maybe it's necessary to tell you that running through 
a list of other criteria that I've never agreed with the importance of has 
no relevance to this discussion. LNH is a different topic, for a different 
time. I thought we were talking about failure to elect CWs, and 
majority-wishes violations.

You continue:

and are vulnerable to burying.

I reply:

You say that you don't repeat, but what do you call that? You've told me 
many times that wv is vulnerabale to burying. Every time you say that, I say 
this: The undesirable results that can happen due to "burying" in wv will 
often happen in IRV and Plurality without anyone using any offensive 
strategy at all. Remember the gentleman who isn't vulnerable to false 
mother-insult reports?

And then I add this: The difference? IRV and Plurailty will give those 
undesirable results automatically, on their own, while in wv they're a 
result of offensive order-reversal. Additionally, in IRV and Plurality, 
those undesirable results can be prevented only by defensive 
favorite-burial, while in wv they can be prevented by mere equal ranking. 
And, in fact, mere truncation is enough to deter the offensive strategy that 
could otherwise cause those undesirable results.

I've answered that statement for you about twenty times now.

You continue:

	I call your "majority wishes" definition the "WV-defined immune set".

I reply:

That's a good name for it, except for three things:

1. Majority wishes is about preferences, and the immune set is about votes.

2. The immune set definition doesn't mention majority.

3. Majority wishes isn't "wv-defined".

The 1st 2 statements are obvious. I'll explain the 3rd one: wv and margins 
are for measuring the strength of a defeat, for the purpose of choosing 
which defeat to drop next in PC, for instance.

Majority wishes is defined in terms of majority pairwise preferences, 
instances of a majority of the voters preferring one candidate to another. 
For one thing, wv and margins refer to votes. But let's ignore that and 
pretend that we were disussing majority rule, which is about votes. A 
majority pairwise vote is an instance of a majority of the voters voting one 
candidate over another. Where do you find wv in that? Majority wishes and 
majority rule aren't wv-defined. They're majorilty-defined. Whether you 
wanted to measure defeat-strength by wv or margins, a majority pairwise 
preference can only mean that a majority prefer one candidate to another.

So, for one thing, your name for majority wishes doesn't make any sense. 
"Majority wishes" is a simple and obviously descriptive name for what I'm 
referring to. For another thing, why do you feel a need to rename what I 
define? It hadn't occurred to me to find a different name for Cardinal 
Pairwise, because it's your proposal. But then why not, if anyone can just 
rename what someone else has defined and named?

I'd said:

>Those things are what I mean by "undesirable results".

You reply:

	There are results that could be said to be more grimly undesirable than
your definition. For example, choosing a Pareto-dominated candidate

I reply:

How could you choose a candidate over whom everyone prefers someone else, 
without violating majority wishes, as I define it?

You continue:
,
choosing a Condorcet loser, choosing a candidate who is the sincere last
choice of 90% of the electorate

I reply:

When there's a CW, how would you do those things without failing to elect 
the CW?

You continue:

If you assume that not
selecting from the WV-defined immune set [James' idiotic name for violating 
majority rule]  is the worst thing that could
possibly happen, then of course it is difficult to argue for any other
method besides WV.

I reply:

Imbecile, I didn't say that violating majorilty wishes was the worst thing 
that could possibly happen. I merely said that it is undesirable. And I also 
included failure to elect a CW under the term "undesirable results".

But even if violating majority wishes isn't the worst thing that can happen, 
if we can avoid violating majorilty wishes, then we also avoid electing 
someone over whom everyone prefer someone else. And if we avoid failing to 
elect a CW, then, when there is one, we also avoid electing a Condorcet 
loser.

In other words, your concerns are covered by my suggestion that it's good to 
avoid undesirable results.

Yesterday I said that I hadn't intended to post these answers yet. This 
message reply is where I intended to post them.

Maybe, instead of electing the CW, your goal is just to elect anyone but the 
Condorcet loser. Maybe, instead of majority wishes, your goal is just to 
avoid electing someone over whom all the voters prefer someone else. Fine. 
Your goals are a lot more modest than mine. As I said yesterday, there's 
nothing wrong with being willing to settle for less. You probably voted for 
Kerry. Yes, I'm repeating what I said yesterday. This reply is where those 
comments belong.

You continue:

	In addition to saying that a result is particularly undesirable if it
elects a very unpopular candidate (as above), one might say that a result
is particularly undesirable if it fails to elect a very popular candidate.
For example, failing to elect a candidate who is the sincere first choice
of 90% of the voters, failing to elect a CW with nearly half of the first
choice votes, etc.

I reply:

And how do you propose to do either of those two things without failing to 
elect a CW?

Do you see why I suggest that you take more care in your replies?

I'm going to post this now, as part one of my reply to your strategy 
posting. I'll post part two tomorrow. If you reply to this part one, instead 
of waiting for part two, please try to make your separate replies to parts 
one and two each only half as long as a reply to both would be. I hesitate 
to reply in two parts, if it could result in two full-length replies from 
you.

Mike Ossipoff

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