[net.politics.theory] The Dilemma of Finding Social Consensus

franka@mmintl.UUCP (Frank Adams) (01/28/86)

In article <524@hounx.UUCP> kort@hounx.UUCP (B.KORT) writes:
>There is an interesting result, due to the Nobel Prize Winning Economist,
>Kenneth Arrow, that the process of finding social consensus is an elusive
>goal.  In Arrow's famous Impossibility Theorem, he shows that there does
>not exist a function, meeting a handful of reasonable and desirable criteria,
>which amalgamates the collection individual preferences into a master
>ordering for society as a whole.  The nonexistence of the so-called Social
>Welfare Function is a surprising result which dashes our hopes of achieving
>consensus without some a priori constraint on individual preferences.

I think you are overstating Arrow's result here.  His results show that there
is no Social Welfare Function derivable from individual preference lists.
This is not equivalent to there being no Social Welfare at all.  If one
assumes that individual preferences can be quantized, and not just ordered,
then there certainly is a Social Welfare Function.

The problem with this in practice is that it is difficult to get an accurate
measure of quantitative preferences.  In particular, just asking people
doesn't work (at least if the results of the poll or election are to be
used to influence what is done), since there is every incentive to
exaggerate the intensity of one's preference.

This, I think, is the fundamental problem of democratic political systems.
Representative democracy goes a long way towards solving it.  Given two
candidates for office, one is likely to agree with one of them on some
issues, and disagree on others.  One's decision on which to vote for is
not based on how many issues one agrees with each on, but on how strongly
one feels about those issues.  (This is neglecting personalities, which
are also a factor.)
-------------------------------------------------------------------------
This discussion belongs in net.politics.theory.  I have cross-posted this
article; follow-ups should be to net.politics.theory only.

Frank Adams                           ihpn4!philabs!pwa-b!mmintl!franka
Multimate International    52 Oakland Ave North    E. Hartford, CT 06108