Godwin's law

Godwin's law (or Godwin's rule of Hitler analogies) is an Internet adage which asserts that "As an online discussion grows longer, the probability of a comparison involving Hitler approaches 1"‍—‌that is, if an online discussion (regardless of topic or scope) goes on long enough, sooner or later someone will compare someone or something to Hitler.

Promulgated by American attorney and author Mike Godwin in 1990, Godwin's law originally referred specifically to Usenet newsgroup discussions. It is now applied to any threaded online discussion, such as Internet forums, chat rooms, and comment threads, as well as to speeches, articles, and other rhetoric where reductio ad Hitlerum occurs.

In 2012, "Godwin's law" became an entry in the third edition of the Oxford English Dictionary.

There are many corollaries to Godwin's law, some considered more canonical (by being adopted by Godwin himself) than others. For example, there is a tradition in many newsgroups and other Internet discussion forums that once such a comparison is made, the thread is finished and whoever mentioned Hitler has automatically lost whatever debate was in progress. This principle is itself frequently referred to as Godwin's law.

Godwin's law itself can be abused as a distraction, diversion or even as censorship, fallaciously miscasting an opponent's argument as hyperbole when the comparisons made by the argument are actually appropriate. Similar criticisms of the "law" (or "at least the distorted version which purports to prohibit all comparisons to German crimes") have been made by American lawyer, journalist and author Glenn Greenwald.

Godwin has stated that he introduced Godwin's law in 1990 as an experiment in memetics.

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