If you’ve spent much time thinking about the political divide in the United States, you’ve hopefully noted how bloody weird it is. Somehow, just about every topic that people want to argue about splits into two camps. If you visualize the vast array of topics you could have an opinion about as a switchboard full of toggles, it seems improbable that so many people in each camp should have nearly identical switchboards, but they do. This can even extend to factual issues, like science—one camp typically does not accept that climate change is real and human-caused.

How in the world do we end up with these opinion sets? And why does something like climate change start an inter-camp argument, while other things like the physics behind airplane design enjoy universal acceptance?

One obvious way to explain these opinions is to look for underlying principles that connect them. Maybe it’s ideologically consistent to oppose both tax increases and extensive government oversight of pesticide products. But can you really draw a straight line from small-government philosophy to immigration attitudes? Or military funding?