Argument from ignorance

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An argument from ignorance (Latin: argumentum ad ignorantiam), or appeal to ignorance ('ignorance' stands for "lack of evidence to the contrary"), is a fallacy in informal logic. It says something is true because it has not yet been proved false. Or, that something is false if it has not yet been proved true. This is also called a negative proof fallacy. This also includes the (false) assumption there are only two options (true or false). There may be as many as four choices:

  1. true
  2. false
  3. unknown
  4. unknowable.[1]

Appeals to ignorance are often used to suggest the other side needs to do the proving. Rules of logic place the burden (responsibility) of proving something on the person making the claim.[2][3]

A logical fallacy is simply a bad argument.[4] Using bad logic does not necessarily mean the argument is false (or true). It is basically a hasty conclusion, one that is arrived at incorrectly.[5] But it still may be convincing to some audiences.[5] This is why it is used in politics and advertising.

Examples[change | change source]

  • "This drug is safe because no-one has found any toxic effects."[6] This only implies that complete testing has been done. It does not say it has been tested completely.
  • "Candidate Smith has never spoken out concerning her views on abortion. We can safely conclude that she must be pro-choice".[7] The argument from ignorance fallacy can be used to dismiss a subject or to argue that it means the opposite.[7]

References[change | change source]

  1. "Argumentum ad Ignorantiam". Philosophy 103: Introduction to Logic. Lander University. 2004. Archived from the original on 30 April 2009. Retrieved 5 November 2014. 
  2. Meryl Runion 2010. How to restore sanity to our political conversations. WordStream Publishing, p. 158.
  3. Douglas Walton 2014. Burden of proof, presumption and argumentation. Cambridge University Press, p. 197.
  4. T. Damer 2013. Attacking faulty reasoning. Boston: Wadsworth, Cengage Learning, 53.
  5. 5.0 5.1 Jerome E. Bickenbach; Jacqueline M. Davies, 1997. Good reasons for better arguments. Peterborough, Ont.: Broadview Press, p. 208.
  6. Reasoning: studies of human inference and its foundations. Adler, Jonathan E. & Rips, Lance J. 2008. Cambridge University Press, p. 405
  7. 7.0 7.1 Jacob E. Van Vleet 2011. Informal logical fallacies: a brief guide. Lanham, MD: University Press of America, p. 9.

Other websites[change | change source]