The boundaries of the thinkable

Marxism or libertarianism, or our topic at hand–environmentalism–all ‘isms’ come with conceptual boundaries–and litmus tests for which opinions fall inside or outside the bounds of reasonableness for that ‘ismatic’ worldview. Can a good conservative back abortion rights or higher marginal tax rates? Or a good liberal condone racial pro1⁄2ling? Or a good communist support China’s transformation into a capitalist state? Or a good paci1⁄2st endorse military intervention in Darfur? Or a good environmentalist support pollution trading permits, French-style nuclear-energy programs, or the Copenhagen Consensus’s low-priority ranking of the threat posed by global warming? These questions resist precise answers because ‘isms’ don’t obey the norms of classical logic (notwithstanding the occasional efforts of thought police to lay out well-de1⁄2ned necessary and suf1⁄2cient conditions for category inclusion and exclusion). ‘Isms’ are best viewed as fuzzy sets with porous, shifting boundaries –and as organized around prototypes. This means that although it is easy at any given juncture in history to design a prototypic ‘ismatic’ belief system (informed observers can rattle off with high interjudge agreement the positions, pro and con, that the prototypical ‘true believer’ should take), it is hard to say at what point one has added or subtracted enough features to or from the prototype that it no longer falls in its original category–and the liberal has become a conservative or vice versa (hence the frequent need for transition categories like ‘neoconservatives’ and ‘neoliberals’). Political psychologists have a longstanding interest in how communities