Julian Sanchez writes on his blog:
Browsing a conservative news site the other day, I was struck by the sheer oddness of that familiar genre of political commentary that treats liberals and conservatives, not just as groups of people with systematic disagreements on policy questions, but as something like distinct subspecies of humanity. The piece that triggered this was something along the lines of “Five Reasons Liberals Are Awful People,” and it had almost nothing to do with any concrete policy question, or ultimately even the broad-brush contours of liberal political thought: It was a string of assertions about broad types of character flaws purportedly shared by liberals, of which their policy views were only a symptom. The same day, I chanced across a piece by Chris Mooney—based on his new book The Republican Brain—making a similar sort of argument from the other side by drawing on recent social science. Then just yesterday, my friend Conor Friedersdorf tweeted a request for good summaries of the liberal view of the right to privacy, and I was again struck by how odd it sounded: Scholars have advanced a whole array of views on the question, and while certainly liberals and conservatives would tend to find different ones more congenial, it seemed like an unhelpful way to map the terrain or illuminate the key points on which various thinkers diverge.
Without denying that political and policy differences are likely to track deeper differences in temperament—differences that shape our preferences and behavior across many domains—it’s worth recalling that the binary nature of our political discourse, featuring two main parties with corresponding ideologies, is a highly contingent feature of our electoral rules. As libertarians never tire of pointing out, there is no particularly compelling philosophical reason that one’s views on abortion, foreign military intervention, environmental regulation, tax policy, and criminal justice should cluster in the particular pattern we find among Republican and Democratic partisans. So we ought to be awfully skeptical about the (growing?) tendency to treat this binary divide as reflecting some essential fact about human nature, or as providing a frame within which to understand all intellectual or cultural life…
Read more here.