Argument from ignorance

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Argument from ignorance (from Latin : argumentum ad ignorantiam), also known as appeal to ignorance (in which ignorance represents "a lack of contrary evidence"), is a fallacy in informal logic. It asserts that a proposition is true because it has not yet been proven false or a proposition is false because it has not yet been proven true. If some proposition has not yet been proved true, we are not entitled on that ground alone to conclude that it is false and vice versa. [1] [2] In debates, appealing to ignorance is sometimes an attempt to shift the burden of proof. The term was likely coined by philosopher John Locke in the late 17th century. [3] [4]

Contents

Examples

"Simply because you do not have evidence that something exists does not mean that you have evidence that it doesn’t exist." [6] [lower-alpha 1]

Appeal to ignorance: the claim that whatever has not been proved false must be true, and vice versa. (e.g., There is no compelling evidence that UFOs are not visiting the Earth; therefore, UFOs exist, and there is intelligent life elsewhere in the Universe. Or: There may be seventy kazillion other worlds, but not one is known to have the moral advancement of the Earth, so we're still central to the Universe.) This impatience with ambiguity can be criticized in the phrase: absence of evidence is not evidence of absence. [8]

Contraposition and transposition

Contraposition is a logically valid rule of inference that allows the creation of a new proposition from the negation and reordering of an existing one. The method applies to any proposition of the type "If A then B" and says that negating all the variables and switching them back to front leads to a new proposition i.e. "If Not-B then Not-A" that is just as true as the original one and that the first implies the second and the second implies the first.

Transposition is exactly the same thing as Contraposition, described in a different language.[ citation needed ]

Null result

Null result is a term often used in science to indicate evidence of absence . A search for water on the ground may yield a null result (the ground is dry); therefore, it probably did not rain.

Argument from self-knowing

Arguments from self-knowing take the form:

  1. If P were true then I would know it; in fact I do not know it; therefore P cannot be true.
  2. If Q were false then I would know it; in fact I do not know it; therefore Q cannot be false.

In practice these arguments are often unsound and rely on the truth of the supporting premise. For example, the claim that If I had just sat on a wild porcupine then I would know it is probably not fallacious and depends entirely on the truth of the first premise (the ability to know it).

See also

Notes

  1. ↑ Though the authors here caution that this may not be an entirely appropriate use of the argument as the onus of providing proof for a substantive statement, like "there are WMDs in Iraq", lies with the party making the claim, not with those opposing it.

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In argumentation theory, an argumentum ad populum is a fallacious argument which is based on claiming a truth or affirming something is good because many people think so.

An argument from authority, also called an appeal to authority, or argumentum ad verecundiam, is a form of argument in which the opinion of an influential figure is used as evidence to support an argument.

References

  1. ↑ Copi, Irving M (2016). Introduction to logic (in 639-2) (14th ed.). Routledge Publication. p. 146. ISBN   9780205820375.{{cite book}}: CS1 maint: unrecognized language (link)
  2. ↑ Hurley, Patrick J (2012). A Concise Introduction to Logic (11th ed.). Boston USA: Cengage Learning. p. 140. ISBN   9780840034175.
  3. ↑ Hansen, Hans V.; Pinto, Robert C., eds. (1995). Fallacies: Classical and Contemporary Readings. University Park, Pa.: Pennsylvania State University Press. ISBN   978-0271014166. OCLC   30624864.
  4. ↑ Locke, John (1690). "Book IV, Chapter XVII: Of Reason". An Essay Concerning Human Understanding. Retrieved 12 March 2015.
  5. ↑ Bennett, Bo. "Argument from Ignorance". www.LogicallyFallacious.com. Retrieved 23 November 2016.
  6. ↑ Brown, Deborah; Key, Brian (22 April 2019). "You look but do not find: why the absence of evidence can be a useful thing". The Conversation. Archived from the original on 15 June 2021. Retrieved 20 June 2022.
  7. ↑ Daily Kos. "Logical Fallacies Bootcamp: Appeal to Ignorance".
  8. ↑ Sagan, Carl. "Chapter 12: The Fine Art of Baloney Detection". The Demon-Haunted World.

Further reading

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