Post post-normal science: ‘systems theories’ with ‘contradictions’

Cover image: President Jimmy Carter leaves Three Mile Island.
April 1st, 1979. Image by: President’s Commission on the Accident at Three Mile Island [Public domain], via Wikimedia Commons.

Post-normal science

Climate change, biodiversity loss, nuclear waste, population limits: the environmental challenges that we face today are not amenable to simplified, data-engrossed decision-making––not when our decisions can produce unacceptably harmful outcomes and must negotiate extreme uncertainties, diverse values, and unknowns. Post-normal science (PNS) champions a broader approach to complex decision-making that goes beyond routine, applied science solutions administered by approved researchers and experts. PNS embraces the ‘extended peer community’ (EPC), recognising the social, political, ethical, and cultural contexts of environmental decision-making, and also recognising the value and depth that non-expert knowledge can bring to decision-making. Essentially, the EPC grounds, or situates, decision processes into real world contexts instead of leaving complex decision-making to occur in disconnected, theoretical spaces.

PNS diagram
The Post-Normal Science diagram: when decision stakes and uncertainty are high, PNS is applicable. (Ravetz, 2006, p.276)

PNS emerged as a response to the limits of Quantitative Risk Assessments (QRA). The failings of QRA came to prominence with the accident at the Three Mile Island nuclear power facility in Pennsylvania, USA (Ravetz, 2006). The reactor was deemed to have a one-in-a-million chance of failing, yet reactor number 2 (TMI-2) failed within three months of commencing commercial operations. This failure highlighted the limits of accepting expert-assessed, quantified risks when the risks pose unacceptable social and environmental harms.

Post post-normal science?

Despite the value generate by the PNS outlook, Jerome Ravetz, one of the co-authors of the 1993 paper on PNS (Funtowicz and Ravetz, 1993), has suggested that PNS is reaching its “obsolescence” and needs to be revised (Ravetz, 2006). Ravetz maintains that PNS still has value, but argues that new frames for addressing the critical social and environmental challenges of our time need to be developed.

Ravetz embraces systems theory as a framework for analysing non-linear, complex, social and environmental dynamics. Within these systems lie ‘contradictions’, or goals and developments that operate counter-purposefully, driving the system towards crisis. ‘Affluence’, as a contradiction, works to expropriate both the poor and the environment, while the poor pursue ‘development’ and “thereby make their own contribution to the ecological crisis” (Ravetz, 2006, p. 276). ‘Affluence’ and ‘development’ are thus interacting and competing demands within the system, and they are driving the system towards a crisis point: a point at which transformation, destruction, or collapse will occur.

In recognition of the complexity of system dynamics, the possible solutions derived from this new approach are many and varied, and not necessarily uniform in applicability. Ravetz suggests applying different solutions to the different feedbacks within the system, such as enacting a top-down, green technology solution for the developed countries with a parallel solution of bottom-up, resilience building technology for the developing countries. These parallel actions could move the whole system towards ecosystem repair and away from a point of crisis.

I’m keen to see how Ravetz and colleagues develop these ideas further and to see how they can be applied to both pressing global issues as well as local issues of importance.


Funtowicz, S. O., & Ravetz, J. R. (1993). Science for the post-normal age. Futures, 25(7), 739-755.

Ravetz, J. R. (2006). Post-Normal Science and the complexity of transitions towards sustainability. Ecological Complexity, 3(4), 275-284.

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