Plausible Fallacies

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Plausible Fallacies

• Paul P Craig
• Chairman, Sierra Club National Committee on
  Global Warming and Energy
• Professor Emeritus of Engineering
• University of California, Davis
• ppcraig_at_ucdavis.edu

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Coal crisis 1865William Stanley Jevons

• The thoughtless and selfish, indeed, who fear
  any interference with the enjoyment of the
  present, will be apt to stigmatize all reasoning
  about the future as absurd and chimerical It is
  true that at best we see dimly into the future,
  but those who acknowledge their duty to posterity
  will feel impelled to use their foresight upon
  what facts and guiding principles we do possess.
  We ought not at least to delay in dispersing a
  set of plausible fallacies about the economy of
  fuel, and the discovery of substitutes for coal,
  which at present obscure the critical nature of
  the question, and are eagerly passed about among
  those who like to believe that we have an
  indefinite period of prosperity before us.
• Jevons, W.S., The Coal Crisis An Inquiry
  Concerning the Progress of the Nation, and the
  Probable Exhaustion of Our Coal-mines.
  reprint1965 ed. 1865, New York Augustus M
  Kelley.p4

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Global Climate Change research comprisesScience
andSocial ScienceTheyre different

• My comments are based on ideas in
• What Can History Teach Us? A Retrospective
  Examination of Long-term Energy Forecasts for the
  U.S.
• Paul P. Craig, Ashok Gadgil, and Jonathan G.
  Koomey. Annual Review of Energy and
• Environment, 27 (83-118) 2002

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Long-range energy forecasts arent like forecasts
based on science

• Long-range forecasting models necessarily make
  assumptions about human behavior (including
  social, institutional and personal) and human
  innovation
• Long-range forecasting models do not meet these
  criteria
• Theyre useful anyway provided one doesnt
  lose track of their limitations

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Usefulness and Accuracy are different concepts.
Long range forecasts are not validatable
US Energy forecasts for 2000(circa 1975)
2000
1975
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Long-range Energy Forecasts are Not Validatable

• Validate as used here is a technical term
• Not validatable means, in essence, that the
  standard principles for testing used in science
  dont apply.
• The term in the sense used here was
  introduced by Hodges and Dewar at RAND. their
  context was military planning
• Is It You Or Your Model Talking? A Framework
  For Model Validation. Hodges J, Dewar J. Rep.
  ISBN 0-8330-1223-1, RAND Corporation, Santa
  Monica, CA 1992.

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Situations described by Validatable Models

• 1) must be observable,
• 2) must exhibit constancy of structure in time,
• 3) must exhibit constancy across variations in
  conditions not specified in the model,
• 4) must permit collection of ample and accurate
  data.

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Non-validatable forecasts can be useful

• To understand the Bounds or Limits on the Range
  of Possible Outcomes
• As training Aids
• As bookkeeping devices. To condense masses of
  data and to provide incentives for improving data
  quality
• As automatic Management Systems Whose Efficacy
  Does Not Require the Model to be a True
  Representation
• continued

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Seven ways in which non-validatable forecasts can
be useful (continued)

• As aids in selling ideas or to achieve political
  ends.
• As aids in Communication and Education
• As aids to Thinking and Hypothesizing

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Nixon-Project Independence Blueprint (1973)

• Energy Independence by 1980
• didnt happen!!!

1973
1980
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Being right is not the same as being correct
Hans Landsbergs RFF (Resources For the Future)
example of being fortuitously correct (1960
forecast, reviewed by Landsberg in 1980)
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Forecasting requires extrapolation
History shows that accepted assumptions sometimes
failed badly
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Lessonsdeer in the headlights

• Keep reminding yourself that the uncertainties
  are huge
• There are few fundamental principles of human
  behavior
• Avoid hubris
• Assess both upside and downside risk in the
  global warming arena its now clear (to the
  Sierra Club, at least) that the risks dominate,
  and the risk of the business as usual approach
  is enormous.
• Research supported by the US Climate Change
  Program is critically important in significant
  part because it may show the consequences of
  inaction.
• Sometimes success occurs because the forecast
  leads to behavioral change. failure is success

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A comment from 1905

• Modern life concentrates its attention with
  ever increasing earnestness upon care for the
  future. ..In strong contrast to this dominance of
  forethought stands that apathy concerning the
  morrow, into which a few of our unfortunates
  slip, but which is essentially characteristic of
  the savage.
• Jevons, H.S., Essays on Economics. 1905, NY
  McMillan. pp280. p66

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When we try to pick out anything by itself, we
find it hitched to everything else in the
universe
Paul Craig Chairman, Sierra Club National Global
Warming and Energy Committee Professor Emeritus,
UC Davis ppcraig_at_ucdavis.edu www.sierraclub.org/
globalwarming