This work offers a cognitive justification for the macro-level organization of democratic life around political parties. Party politics tends to organize debate into intense clusters of argument among people (partisans for the one or the other party) who agree in broad outline about how to solve problems, but who disagree vigorously about the specifics. Links between these clusters are much rarer than links within them, and are usually mediated by competition. Under a cognitive account, one might see each of these different clusters as engaged in exploring the space of possibilities around a particular solution, maintaining some limited awareness of other searches being performed within other clusters, and sometimes discreetly borrowing from them in order to improve competitiveness, but nonetheless preserving an essential level of diversity (cf. Huckfeldt et al., 2004). Such very general considerations do not justify any specific partisan arrangement, as there may be better (or worse) arrangements available. What it does is highlight how party organization and party competition can have benefits that are hard or impossible to match in a less clustered and more homogenous social setting. Specifically, it shows how partisan arrangements can be better at solving complex problems than non-partisan institutions, because they better preserve and better harness diversity.
This leads us to argue that democracy will be better able to solve complex problems than either markets or hierarchy, for two reasons. First, democracy embodies a commitment to political equality that the other two macro-institutions do not. Clearly, actual democracies achieve political equality more or less imperfectly. Yet if we are right, the better a democracy is at achieving political equality, the better it will be, ceteris paribus, at solving complex problems. Second, democratic argument, which people use either to ally with or to attack those with other points of view, is better suited to exposing different perspectives to each other, and hence capturing the benefits of diversity, than either markets or hierarchies. Notably, we do not make heroic claims about people’s ability to deliberate in some context that is free from faction and self-interest. Instead, even under realistic accounts of how people argue, democratic argument will have cognitive benefits, and indeed can transform private vices (confirmation bias) into public virtues (the preservation of cognitive diversity). Democratic structures – such as political parties – that are often deplored turn out to have important cognitive advantages.