31 March 2011

Climate catastrophist logical fallacies

Inspired by this unconsciously hilarious report in the Guardian about unexpectedly cold weather causing an increase in greenhouse gas ejaculations emissions because people selfishly wished to stay warm, I thought I'd run through the offences against logic commonly committed by the climate catastrophists. I doubt if the list is definitive!
  • Ad hominem: seeking to discredit an argument by attacking an opponent's character (or funding!)
  • Affirming a disjunct: A or B; A therefore not B
  • Affirming the consequent: if A then B; if B therefore A
  • Appeal to authority: a statement is correct because it is made by a person or persons regarded as authoritative
  • Appeal to probability: because something could happen, it will happen
  • Argument from ignorance: something is true because it has not been proved to be false
  • Argument from repetition: something discussed so often that it does not need further discussion
  • Argumentum ad populum: because many people believe something to be true, it must be true
  • Argumentum verbosium: an argument too complex or verbose to make it possible to deal with all its details
  • Bare assertion: an argument is assumed to be true because it says it is true
  • Base rate: to make a probability judgment without taking into account empirical statistics about the probability
  • Causal oversimplification: attributing a phenomenon to one cause when there are many
  • Cherry picking evidence
  • Circular causation: where the result of something is asserted to be its cause (carbon dioxide)
  • Cum hoc ergo propter hoc: correlation between two factors does not imply one causes the other
  • Demanding negative proof: avoiding the burden of proof by demanding proof of the contrary
  • Denying the antecedent: if A then B; if not A therefore not B
  • Equivocation: use of terms with more than one meaning without specifying which meaning is intended
  • False analogy
  • False attribution: appeal to false, fabricated, biased or irrelevant evidence
  • False dichotomy: where two alternatives are declared to be the only possible options when there are more
  • Jumping to a conclusion
  • Moving the goalposts: changing the terms of the argument ("global warming" becoming "climate change")
  • Negative proof: because a premise cannot be proved to be wrong, therefore it must be right
  • Over-dramatization
  • Over-simplification
  • Petitio principii: where the conclusion of an argument is assumed in one or more of its premises.
  • Post hoc ergo propter hoc: B follows A, therefore A causes B
  • Reductio ad absurdam (a.k.a. slippery slope): seeking to deny that A is beneficial because A x 1000 is harmful
  • Regression fallacy: ascribes cause where none exists
  • Reification: when an abstraction or hypothesis is regarded as having a concrete existence
  • Special pleading
  • Suppressed correlative: redefining incompatible premises so that one encompasses the other


  1. Argumentum meteorologium veritatis: if the Met Office says its true then it is true

  2. LOL. A variant of Appeal to Authority, I think.