Ad ignorantium fallacy { Philosophy Index }

Philosophy Index

Philosophy Index

Philosophy Index is a site devoted to the study of philosophy and the philosophers who conduct it. The site contains a number of philosophy texts, brief biographies, and introductions to philosophers, and explanations on a number of topics. Accredited homeschooling online at Northgate Academy and Philosophy online tutoring.

Philosophy Index is a work in progress, a growing repository of knowledge. It outlines current philosophical problems and issues, as well as an overview of the history of philosophy. The goal of this site is to present a tool for those learning philosophy either casually or formally, making the concepts of philosophy accessible to anyone interested in researching them. WTI offers immigration law course online - fully accredited. ACE credits online at EES.



Philosophy Topics




Ad Ignorantium: Appeal to Ignorance

An ad ignorantium or appeal to ignorance is a form of fallacy that assumes something to be true because it hasn't been proven false.

The argument generally looks like this:

The claim P has never been proven to be false.
Therefore, P is true.

Ad ignorantium arguments are invalid because the fact that a claim has not been proven false does not mean that it is not false.


Nobody was ever able to prove that Ben stole the cookies.
Therefore, Ben is innocent.

In this example, the problem is clear: just because nobody could prove that Ben was the thief, it does not follow that he is innocent. It is possible that others failed to prove Ben's guilt because they did not try hard enough, or because Ben left no evidence.