The genetic fallacy, also known as fallacy of origins, fallacy of virtue, is a fallacy of irrelevance where a conclusion is suggested based solely on something or someone's origin rather than its current meaning or context. This overlooks any difference to be found in the present situation, typically transferring the positive or negative esteem from the earlier context.
The fallacy therefore fails to assess the claim on its merit. The first criterion of a good argument is that the premises must have bearing on the truth or falsity of the claim in question. Genetic accounts of an issue may be true, and they may help illuminate the reasons why the issue has assumed its present form, but they are irrelevant to its merits.
Argument from age ("Wisdom of the Ancients")
This is a common version of the genetic fallacy where the thing in question is very new or old, so it must be better. Examples include products advertised as "New!" or "Old Fashioned Hamburgers".
"Not invented here"
Another variation is to dismiss outside ideas because they did not originate from here. "This is the way we've always done it." This fallacy is often abbreviated "NIH". The converse of this is also false. Being foreign made does not necessarily mean something is better.
From Attacking Faulty Reasoning by T. Edward Damer, Third Edition p. 36:
|“||"You're not going to wear a wedding ring, are you? Don't you know that the wedding ring originally symbolized ankle chains worn by women to prevent them from running away from their husbands? I would not have thought you would be a party to such a sexist practice."||”|
There are numerous motives explaining why people choose to wear wedding rings, but it would be a logical fallacy to presume those who continue the tradition are doing so with the intent of promoting sexism.
From With Good Reason: An Introduction to Informal Fallacies by S. Morris Engel, Fifth Edition, pg. 196:
|“||America will never settle down; look at the rabble-rousers who founded it.||”|
A commonly occurring example of this style of reasoning can be called the "etymological fallacy". This presents arguments based on the supposed real meaning of certain words, where that "real" meaning is in fact what the word meant centuries ago, or what its root word (in Latin, Greek etc.) meant. A popular tactic, it is easily shown to be fallacious and misleading. Thus:
|“||"Has he arrived yet?" "No, he came by car, not by boat!"||”|
This is not merely a non-sequitur. It reflects that fact that the first speaker simply accepts the contemporary meaning of "arrive", whereas the second recalls the Latin origin: ripa meaning "shore" (compare also the words "river" and "Riviera"), whereby the English word "arrive" contains within it the idea of disembarkation.
The genetic fallacy is committed when there is the assumption that the current item must be similar to its origin in some way. A common erroneous invoking of the genetic fallacy is committed when the example contains the initial assumption that the current item is not similar to its origin in some way, yet there is data to demonstrate that there is, in fact, a degree of similarity, suggesting a causal or logical connection. Christian apologist Greg Koukl introduces the fact that children of a particular religion very frequently descend from parents of that same religion, then attempts to dismiss the claims that this is evidence that parents influence their children's religious conclusions by suggesting this is a case of the genetic fallacy.  So while the genetic fallacy has been committed in the case in which someone assumes the child of a Republican is therefore also a Republican, in the case in which the assumption is that the children of a Christians are not necessarily Christian, yet, in fact, they statistically are, the genetic fallacy has not been committed.
- "A List Of Fallacious Arguments". Retrieved 6 October 2012.
- Attacking Faulty Reasoning: A Practical Guide to Fallacy-Free Arguments (Third Edition) by T. Edward Damer, chapter II, subsection "The Relevance Criterion" (pg. 12)
- With Good Reason: An Introduction to Informal Fallacies (Fifth Edition) by S. Morris Engel, chapter V, subsection 1 (pg. 198)
- Honderich, Ted, ed. (1995). "Genetic fallacy". The Oxford Companion to Philosophy. Oxford University Press. ISBN 978-0-19-866132-0.
- Koukl, Greg. "French Former Atheist Naturalist becomes Christian". Stand To Reason. Retrieved 8 December 2013.