[lbo-talk] Arrow (Was Re: law)

andie nachgeborenen andie_nachgeborenen at yahoo.com
Sat Sep 11 01:54:16 PDT 2004


ALl of this is true, but the point of bringing up the Arrow Theorem is that there is a deep theoretical problem with democracy even if we fix all of that, and it doesn't even make us blink in our support for democracy. Rather, we do thes ort think Ted does, and try to avoid it theoretically, or the sort of thing you do, and blow it off -- which is fine, after all all, it is only a theoretical problem, while the ones you list are practical problems _for_, rather than _with_ democracy.

That was the point I was making to BM -- it doesn't matter to us if we have a justification of democracy or an answer to the objections or problems. We'd like a justification, but as long as we agree on democratic procedures, it's onlt icing. Democracy (as Rorty says) is prior to philosophy, deeper than justification. jks

--- joanna bujes <jbujes at covad.net> wrote:


> The only real paradox here is #5. But even that
> strikes me as trivial
> compared to the actual problems of
>
> -- lack of education
> -- incessant brainwashing
> -- gerrymandering
> -- intimidation/exclusion of minority voters
> -- fraud
>
> Let's tackle those first...and then see what
> remains.
>
> Joanna
>
>
> andie nachgeborenen wrote:
>
> >Warning, Slightly Technical Stuff Here:
> >
> >Yes, Arrow's results concern voting. But voting is
> how
> >things are decided in a democracy. The math is
> >rock-solid. Here's a standard proof:
> >
>
>http://www.tulane.edu/~dnelson/COURSES/IntroPE/arrow.pdf
> >
> >That, plus the impotrtance of the result, is why
> Arrow
> >won the Nobel Prize, although Michigan didn't find
> the
> >result interesting and (before Arrow won the Nobel)
> >turned him down for tenure.
> >
> >Arrow showed that you cannot have a voting system
> that
> >satisfies the following conditions, four of which
> seem
> >absolutely crucial to any system that calls itself
> >democratic:
> >
> >1) Nondictatorship (no one person's vote decides an
> >issue (except as a tie breaker);
> >
> >2) Monotonicity: No choice can be harmed in a vote
> by
> >being ranked higher by an individual, or (stronger)
> >
> >2a) Pareto optimality: if everyone prefers a
> certain
> >choice, it will be the outcome society prefers
> >
> >3)Universality: the voting system can in principle
> >rank all choices that citizens might make relative
> to
> >one another
> >
> >4) Citizen Sovereignty. Every possible ranking of
> >choices can be achieved from some set of individual
> >votes.
> >
> >5)Independence of irrelevant alternatives: You
> should
> >not be able to affect the outcome of a vote by
> >introducing another choice into it, unless the
> extra
> >choice actually wins (The Nader problem!)
> >
> >That is, in social choice-ese. the outcome of a
> choice
> >among a limited set of options should be
> consiststent
> >with the choice among all options, so that choices
> >outset the subset (irrelevant ones) should not
> affect
> >the choice within it. (This one is the least
> >intuitive, but it seems like it should be true).
> >
> >The theorem is that with two voters and three
> options,
> >you cannot satisfy these conditions at the same
> time:
> >not all choice sets are attainable without
> violating
> >at least one of them.
> >
> >There is a vast literature on getting out of the
> >paradox because it is very trouble to democrats
> that
> >no voting system can satisfy these criteria, all of
> >which appear fundamental to democracy.
> >
> >The problem isn't that no _single_ voting system
> can
> >accurately represent the will of the majority --
> you
> >can't _combine_ voting systems to avoid the
> paradox.
> >
> >The problem rather sugests that there is no such
> thing
> >as "the will of the majority," if that is taken to
> be
> >an aggregate of individual preferences. That of
> >course is an interpretation, not a result. It's
> >embraced by right wing, market-oriented public
> choice
> >theorists like James Buchanan who want to take
> >everything out of the public realm and make choices
> by
> >buying and selling instead. So it is even more
> >troubling for the left.
> >
> >Nonetheless I suggest that nothing, not even a
> >mathematical proof, would make us give up our faith
> in
> >democracy. Even the public choice crowd does not
> >advocate getting rid of democratic politics, just
> >limiting its scope a lot.
> >
> >jks
> >
> >
> >
> >
> >--- John Adams <jadams01 at sprynet.com> wrote:
> >
> >
> >
> >>On Thursday, September 9, 2004, at 11:24 PM, andie
> >>nachgeborenen wrote:
> >>
> >>
> >>
> >>>By way of illustration, the economist Kennth
> Arrow
> >>>
> >>>
> >>has
> >>
> >>
> >>>a theorem -- a mathematical proof -- that four or
> >>>
> >>>
> >>five
> >>
> >>
> >>>absolutely fundamental and completely obvious
> >>>conditions for democracy are inconsistent.
> >>>
> >>>
> >>If I remember correctly--seems like David Duke was
> >>running for Senate
> >>that year, so it would've been '90 when we had the
> >>seminar--Arrow's
> >>work is specific to voting systems. This was given
> >>by the math
> >>department, though, so I can't swear whoever
> >>presented interpreted him
> >>correctly. (Didn't Arrow get a Nobel Prize in
> >>economics for this? There
> >>was some discussion during the seminar about
> whether
> >>the math of it was
> >>worthy--I seem to recall suggesting it was the
> >>cleverness of his
> >>application of the math that was being recognized,
> >>but then, that's the
> >>sort of argument I make around people more
> >>knowledgeable than myself.)
> >>
> >>
> >>
> >>>That doesn't make us think, oops, better go with
> >>>dictatorship. It makes us think there is
> something
> >>>funny about Arrow's proof, although no one has
> >>>
> >>>
> >>been
> >>
> >>
> >>>able to say just what.
> >>>
> >>>
> >>I recall the interpretation of his work as being a
> >>bit different--more
> >>that no single voting system can be guaranteed to
> >>accurately represent
> >>majority will given all possible election results.
> >>It's been a long
> >>time, though, and I was busy that fall, so I'm not
> >>shocked if I
> >>misremember.
> >>
> >>All the best,
> >>
> >> John A
> >>
> >>___________________________________
> >>
>
=== message truncated ===

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