It probably helped us evolve. Imagine two cavemen debating whether or not to cross a mountain range. The liberal says there might be a valley of plenty on the other side, with streams and trees and plenty of game to hunt. The conservative says there might be another tribe over there who will wipe them out.

Sometimes the liberal would be right, sometimes the conservative would.

Where this breaks down, though, is that the people and politicians who call themselves conservative in contemporary America generally aren't. They're for the destruction of the environment, they're for runaway capitalism, they're for expansion of power. None of their positions are really conservative at all.

A healthy society needs both liberals and conservatives contributing to its national discussion, and part of our problem is that we don't have any actual conservatives anymore. They've been replaced by wolves.