[EM] FW: IRV Challenge - Press Announcement

[Kristofer Munsterhjelm]

Markus Schulze wrote:
> Dear Jonathan Lundell,
> 
> I wrote (7 Oct 2008):
> 
>> Well, the second paper is more general. Here they use
>> Arrow's Theorem to argue why monotonicity has to be
>> sacrificed.
> 
> You wrote (7 Oct 2008):
> 
>> Or at least that something has to be sacrificed. Do
>> you see that as a problem?
> 
> Well, monotonicity is actually not needed in Arrow's
> Theorem. Therefore, Arrow's Theorem is frequently
> stated as saying that no single-winner election
> method can satisfy (1) universal admissibility,
> (2) Pareto, (3) nondictatorship, and (4) independence
> from irrelevant alternatives.
> 
> Therefore, using Arrow's Theorem to argue that
> monotonicity should be sacrificed to get
> compatibility with the other criteria seems
> to be odd.

If you want to be generous, you could read the argument as "all methods 
fail one of Arrow's criteria; monotonicity failure is a result of this, 
and if a method doesn't fail monotonicity, it'll fail something else". 
That's still odd, though, because you can turn the argument around and 
say "well, then if you think Arrow failure makes all methods equal, 
there's no disadvantage to using Condorcet, but if you think some 
criteria are more important than others, then there's an advantage to 
using Condorcet, therefore in any case there's no disadvantage to using 
Condorcet".