Foundations of Science

, Volume 2, Issue 2, pp 207–236 | Cite as

The Precautionary Principle: Scientific Uncertainty and Type I and Type II Errors

  • John Lemons
  • Kristin Shrader-Frechette
  • Carl Cranor


We provide examples of the extent and nature of environmental and human health problems and show why in the United States prevailing scientific and legal burden of proof requirements usually cannot be met because of the pervasiveness of scientific uncertainty. We also provide examples of how may assumptions, judgments, evaluations, and inferences in scientific methods are value-laden and that when this is not recognized results of studies will appear to be more factual and value-neutral than warranted. Further, we show that there is a "tension" between the use of the 95 percent confidence rule as a normative basis to reduce speculation in scientific knowledge and other public policy and moral concerns embodied by the adoption of a precautionary principle. Finally, although there is no precise agreement regarding what a precautionary principle might entail, we make several recommendations regarding the placement of the burden of proof and the standard of proof that ought to be required in environmental and human health matters.

Precautionary principle Sustainable development Agenda 21 Scientific uncertainty 


Unable to display preview. Download preview PDF.

Unable to display preview. Download preview PDF.


  1. Cranor, C. (1993), Regulating Toxic Substances: A Philosophy of Science and Law, New York: Oxford University Press.Google Scholar
  2. Funtowicz, S.O., J.R. Ravetz (1995), ‘Science for the Post Normal Age’, in: Westra L., Lemons J., (eds.), Perspectives on Ecological Integrity, Dordrecht, The Netherlands: Kluwer Academic Publishers.Google Scholar
  3. Johnson, S.P. (1993), The Earth Summit. The United Nations Conference on Environment and Development (UNCED), London: Graham & Trotman/Martinus Nijhoff.Google Scholar
  4. Lemons, J. (ed.), (1996), Scientific Uncertainty and Environmental Problem Solving, Cambridge, MA: Blackwell Science, Inc.Google Scholar
  5. Lernons, J., Brown D.A. (eds.), (1995), Sustainable Development: Science, Ethics, and Public Policy, Dordrecht, The Netherlands: Kluwer Academic Publishers.Google Scholar
  6. Lemons, J., Malone C. (1989), ‘Frameworks for Decisions About Nuclear Waste Disposal’, International Journal of Environmental Studies, 34, 263-270.Google Scholar
  7. Shrader-Frechette, K.S. (1993), Burying Uncertainty, Berkeley, CA: University of California Press.Google Scholar
  8. Shrader-Frechette, K.S., McCoy, E.D. (1993), Method in Ecology, Cambridge, England: Cambridge University Press.Google Scholar

Copyright information

© Kluwer Academic Publishers 1997

Authors and Affiliations

  • John Lemons
    • 1
  • Kristin Shrader-Frechette
    • 2
  • Carl Cranor
    • 2
  1. 1.Department of Life SciencesUniversity of New EnglandBiddefordUSA
  2. 2.Environmental Sciences and Policy Program and Department of PhilosophyUniversity of South FloridaTampaUSA

Personalised recommendations