Liberal vs Conservative. Left vs Right. Us vs Them.
Society puts a lot of effort, it would seem, in splitting itself into groups. More often than not we find ourselves falling into one of two groups. The tendency to form two groups, not three or four, may be for simplicity, or a coincidence. But that's unlikely. Otherwise we could form one group, that's simpler. What if this tendency does not depend on the subject of discussion, but is rather inherent to how humans form opinions? If our opinions depend on the process itself, how much of your beliefs came from you versus a reaction to the other side?