An open access publication of the American Academy of Arts & Sciences
Spring 2008

The boundaries of the thinkable

Authors
Philip Eyrikson Tetlock and Michael Oppenheimer

Philip E. Tetlock is the Mitchell Endowed Chair at the Walter A. Haas School of Business at the University of California, Berkeley. He is the author of “Expert Political Judgment: How Good is It? How Can We Know?” (2005) and coeditor of “Unmaking the West: What-If Scenarios That Rewrite World History” (with Geoffrey Parker and Richard Ned Lebow, 2006).

Michael Oppenheimer is the Albert G. Milbank Professor of Geosciences and International Affairs at Princeton University. He is the author of more than eighty journal articles and coauthor of “Dead Heat: The Race Against the Greenhouse Effect” (with Robert H. Boyle, 1990). He is also a science advisor to Environmental Defense, but the views expressed here are his own.

Be it conservatism or liberalism, 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 profiling? Or a good communist support China’s transformation into a capitalist state? Or a good pacifist 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-defined necessary and sufficient 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 of cobelievers define the boundaries of the thinkable and where they set their thresholds for issuing fatwas, excommunicating deviants, excluding former participants from coalitions, or just shunning someone at a cocktail party. Our starting point is Tetlock’s sacred value protection model (SVPM),1 which takes as its starting point an undeniable fact of political life: the tendency of like-minded souls to coalesce into communities of cobelievers dedicated to defending and advancing shared values. The SVPM posits that cobelievers seek reassurance from each other that their beliefs are not mere social conventions but rather are anchored in backstop or sacred values beyond challenge. These values can be as diverse as the causes around which human beings cluster: in pro-life communities, it would be bizarre to challenge the sacred mission of saving the unborn; in libertarian communities, it would be bizarre to challenge the sacred status of property rights; and in scientific communities or groups relying on scientific expertise, it would be bizarre to challenge the notion that assertions about nature can be tested objectively (within a range of uncertainty) and deep truths revealed. Those foolish enough to ask why sacred values are so special–what is wrong with stem cell research or faking data or redistributive taxation?–reveal themselves to be dim-witted or ill-intentioned outsiders who just don’t get it.

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Endnotes

  • 1P. E. Tetlock, “Social-Functionalist Frameworks for Judgment and Choice: The Intuitive Politician, Theologian, and Prosecutor,” Psychological Review 109 (2002): 451–472.
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