  : But that's not what IIA says.  Your example is a change from a linear order M > V (with W unknown, in one of the 5 possible positions) to a linear order V > M > W.  But this is nothing but a change in preferences; if W was later discovered to be infeasible, then the preferences would be V > M  a change from the original.  Under IIA there is no change, and given only M and V preferences would be M > V.  The example has nothing to do with IIA. : Sure, people can change their minds and this is sometimes (rarely) analyzed in social choice theory.  But it's a different thing entirely from IIA. :   |    