Reflections on Timescales Part I: Commensurability in the Anthropocene

This piece is the first in a series of posts reflecting on the TIMESCALES Conference held from October 20th through October 22nd at the University of Pennsylvania and sponsored by the Penn Program in the Environmental Humanities. The conference program can be found here


Among the many legacies left in the wake of the Vietnam War is that of U.S. Secretary of Defense Robert McNamara, whose role in escalating American military involvement in Southeast Asia shaped the course of world history as well as the experiences of those unfortunate enough to get caught in the crossfire of some of the Cold War’s hottest battles. The Secretary’s name has become a label for what some have called the “quantitative fallacy,” or the mistake of relying on measurable data at the expense of all other information when making decisions about complex problems. The “McNamara Fallacy” has become a warning for the dangers awaiting those who let a limited set of data stand for complex conditions in their many dimensions, just as McNamara arguably did when he used crude metrics like body counts as proxies for military success.

 U.S. Secretary of State Robert McNamara, Time, July 1966

U.S. Secretary of State Robert McNamara, Time, July 1966

In an age in which quantitative metrics of wealth, production, and pollution play such a prominent—even determinative—role in environmental policy, coming to terms with the dangers of committing McNamara’s fallacy seems timelier than ever. The interdisciplinary field of environmental humanities is especially well-equipped to guard against this error because it fosters conversations between scientists and humanists—that is to say, between those who specialize in analyzing quantitative data in those who specialize in alternative methods of inquiry. These conversations can help scholars on both sides of the proverbial divide between quantitative and qualitative scholarship come to terms with the limits of their methods while revealing opportunities for cross-disciplinary collaboration. 

I had the privilege of witnessing such a conversation in late October at the University of Pennsylvania’s TIMESCALES conference. During one of the conference’s final panels during the afternoon of Saturday, October 22nd, a geologist and an ethicist discussed the relationships between their disciplines, a topic made especially urgent by climate change and the challenges it poses to both scholars and citizens of the Anthropocene. The question posed to our two panelists was: “are long-range data and human ethics commensurable?” An audience of medical doctors and architects, social scientists and comparative literature scholars, anthropologists and engineers listened intently to the discussion. 

Environmental scholarship often tests the boundaries of what is measurable precisely because its subject matter so often inhabits the extremes of both spatial and temporal scales. Dave Evans, Professor of Geology and Geophysics at Yale University, highlighted at the outset of his presentation his discipline’s perennial challenge of attempting to measure geological phenomena dating back millions and even billions of years. Indeed, Evans insisted, a million years amounts to a drop in the bucket for a geologist whose timescales extend into the eons, and with these massive timescales come problems of imprecision and uncertainty. Advances in methods such as carbon dating have given scientists access to levels of precision unimaginable even a decade ago, yet Evans acknowledged that our power to measure phenomena in deep time remains limited, a fact that geologists take as an invitation to find creative proxies for data that cannot be taken directly. Especially memorable was Evans’ description of a promising method of estimating prehistoric levels of carbon in the atmosphere which measures the prevalence of holes in plant matter called “stomata” that serve as portals for carbon dioxide.

By expanding the range of what empirical scientists seek to measure, environmental science can extend the reach of our knowledge of climate change across deep time, a contribution that Evans hopes will allow us to place contemporary climate change into what he calls “geological perspective.” However, even as measurement techniques increase in sophistication, uncertainty remains. This means scientists have a duty to alert the various publics who seek to learn from their findings to the uncertainty and imprecision of their data. Whether estimating greenhouse gas levels in the deep past or projecting them into the future, scientists must present their data with the caveat that none of their findings are certain—but that they are nonetheless urgent. 

Whereas Professor Evans focused on expanding what quantitative metrics can capture while retaining an appreciation for the uncertainty intrinsic to scientific knowledge, Dale Jamieson focused on the problem of translating scientific data into ethical imperatives that spur action. As a professor of environmental studies, philosophy, and bioethics at New York University, Jamieson has long been concerned with a tendency in both science and ethics to produce abstract accounts of environmental problems that go beyond both human comprehension and motivations. The question he asked us was: how are human beings supposed to feel about long-range data, and how might that translate into action? For Jamieson, the trouble is that we have yet to develop moral feelings about atmospheric gases. For one thing, who is responsible for them? By showing his audience a pie chart of nation-states that are the largest annual greenhouse gas emitters alongside a similar chart of the largest cumulative emitters, Jamieson reminded us that Earth’s 500 million richest people—“that’s us,” he quipped—are responsible for half of anthropogenic greenhouse gas emissions. The problem is that, while general responsibility for climate change is quite clear, the moral and individual responsibility is not nearly so clear from day to day. For Jamieson, if climate change is under-moralized, then morality must change. It must be made more proximate and dramatic to our moral senses so that an increase in greenhouse gases has the same visceral force as more conventional offenses to morality like slavery or animal cruelty. 


 James Scott,  Seeing Like a State , Yale University Press, 1998

James Scott, Seeing Like a State, Yale University Press, 1998

The challenges of measurement and interpretation posed by our panelists point to perennial problems of commensurability the have long plagued scholars across many disciplines, and these problems are not limited to the realms of science and ethics. As political scientist and anthropologist James Scott has argued, models and measurements contribute to a politics of legibility in which some things are made visible while others are made invisible. If a national forest is being managed according to simple metrics like lumber yield and acreage of mature growth, the manager will understand the forest to be a means of maximizing revenue and lumber production, forcing to the wayside other concerns like biodiversity and local memories about the forest as a place for lived experiences. Similarly, if scholars study climate change primarily through metrics of greenhouse gases in the atmosphere, other aspects of the globe’s environmental crises—habitat loss, mass extinctions, monocultures in food, environmental health—may fade to the background. Here we are confronted with a sobering thought: if we were to wave a magic wand and greenhouse gas emissions dropped to zero tomorrow, many of the most urgent environmental problems would remain. 

This suggests that environmental scholars may commit their own McNamara Fallacy when they focus too much on metrics of greenhouse gas emissions. As Rob Nixon has argued, the slow violence of environmental degradation requires scholars and activists to turn their gaze to the lived experiences of those most vulnerable to the effects of climate change and other environmental problems. Long-range climate data may be commensurable with (a certain kind of) ethics, but it may not be commensurable with the full range of environmental problems facing the planet or with the full range of consequences stemming from them.

 Rob Nixon,  Slow Violence and the Environmentalism of the Poor , Harvard University Press, 2011. 

Rob Nixon, Slow Violence and the Environmentalism of the Poor, Harvard University Press, 2011. 

Commensurability refers to the capacity for two different things to be measured by the same standard. To make two different things commensurable requires an act of translation into a common language or structure that allows the two to be compared as apples to apples rather than as apples and oranges. This is often done by making qualitative comparisons into quantitative ones. The problem, as James Scott and others have noted, is that important details often get lost in the process of translation. The discussion between geologist Dave Evans and ethicist Dale Jamieson helped reveal what can be lost in translation between science and ethics, and the Q&A session at the end of the panel discussion helped point the way toward what we might do to address the resulting gaps.  

However, one important dimension of (in)commensurability remained unaddressed. The McNamara Fallacy is especially relevant to an increasingly influential approach to solving environmental problems that seeks to translate environmental costs and benefits into prices that can be used to implement such policies as a carbon tax or cap-and-trade markets. This strategy of translating environmental conditions into market metrics has even been employed to measure the economic benefits of entire ecosystems, a metric that environmental economists call “ecosystem services.” The advantage of this approach is that money and markets are powerful. If something we deem important can be translated into an economic idiom, it stands a better chance of receiving support in our current politics. After all, money talks. The disadvantage is merely the other side of the same coin—if something does not pay, then it does not register in market metrics. For example, the environmentalism of the poor does not pay, almost by definition. The market may do a passable job of measuring the bottom line, but it almost certainly fails in measuring our ethical commitments or the diverse consequences of our carbon footprint.

 Naomi Klein,  This Changes Everything , Simon & Schuster, 2015. 

Naomi Klein, This Changes Everything, Simon & Schuster, 2015. 

Given all of this, our panel discussion left me wondering: even if long-range metrics of climate change translated directly into an ethical obligation to act, how would that ethical obligation balance with others? Economics, as its practitioners love to remind us, is a matter of tradeoffs. When faced with competing goals, how do environmentalists justify their goals over others? Can it be done solely by translating ethical imperatives into market imperatives? That is to say, are long-range climate data and economics commensurable? If voices as diverse as Pope Francis and Naomi Klein are right, then the translation problem may extend beyond science and ethics to the dismal science of economics, and the most important dimension of the McNamara Fallacy may lie not in carbon metrics but in dollars and cents.