“Why Haven’t We Been Taught This Material Until Now?”
20th July 2016
As always, near the end of the course I cover foundational public-choice economics – including an introduction to Arrow’s Impossibility Theorem. Summarizing the conclusions of this literature as succinctly as my meager writing skills permit, Arrow’s theorem – made famous by Nobel laureate economist Kenneth Arrow (and often explained using examples from the work of the Scotsman Duncan Black) – says that it is impossible for any collective decision-making mechanism or procedure to generate outcomes that reflect only the preferences of the choosers. The outcomes of all collective decision-making mechanisms or procedures – including majoritarian voting – necessarily are determined in part by the manner in which those mechanisms or procedures are used to settle upon outcomes. Put differently, Arrow proved that it is impossible to devise any collective decision-making mechanism or procedure that generates results free of the influence of arbitrary factors (that is, factors that reasonable people believe should not play a role in determining the outcome of decision-making procedures).
The short conclusion for majoritarian voting is this: the preferences of the voters are not the only factors that determine the outcomes of elections. If the manner in which the vote in conducted is changed, the outcome of an election will change even if no voter’s preferences change.
Put even more succinctly: in almost all elections, there isn’t only one correct outcome. There isn’t one outcome that reflects the individual-voters’ collective “preference” better or more accurately than some other possible outcomes. Stated differently, in almost all collective-decision-making settings, there is no “will of the people.” It’s a mistake to anthropomorphize a group of people. Each individual has preferences; a collection of individuals has only a collection of individual preferences and not a separate and determinate group preference.
Democracy is a means, not an end, and sometimes not a very good one.