Last time I talked about what the people want, there were two main points.
First, there are always more than two options. The point of this is that if even in seemingly two-party systems such as that here in the US, there are so-called third parties, and the presence of third-party candidates is sometimes consequential. The big scary example is Allende in Chile in the 1970s; the less scary but more proximate example (for US readers) is Perot in the 1992 US presidential election.
Second, once there are more than two options, what the people "want" is hard to define. Using the Borda count and plurality rule voting methods, I showed how society's first choice depends on the manner in which people decide.
In the academic literature on "social choice," as it's called, the issue is one of preference aggregation and whether it's possible to aggregate preferences in a rational, fair way.
Today, I'll start with a statement of Arrow's Theorem, which answers that question with a resounding "No, it's not possible. Sorry." I'll follow with some intuition, and in future posts I'll flesh out the ideas.
