The fundamental problem of social choice

The fundamental problem of social choice is aggregating individual preferences into a collective preference function that…

The fundamental problem of social choice is aggregating individual preferences into a collective preference function that allows society to make a decision. We approached this question with both normative and positive theory and surprisingly found that they both point in the same direction. Normatively, Arrow’s Impossibility Theorem started with a reasonable set of requirements for the social choice process and showed that they were internally inconsistent. Positively, McKelvey’s Theorem showed that when the mechanics of social choice do not provide a decisive choice under majority rule, chaos ensues and democratic ideals are lost. Assume you are talking with a friend (also a political science major) who has not taken this class.

  1. Explain Arrow’s and McKelvey’s Theorems to your friend in terms that he or she can understand.
  2. Indicate how the two theorems are related
  3. Tell your friend why Professor Roberts can’t sleep at night when he thinks about the results of these theorems. That is, describe what is disturbing about the theorems.