Difficult as it may be, it is vitally important to separate argument sources and styles from argument content. In argument the medium is not the message.1
Despite its name, the Genetic Fallacy has nothing to do with genes or heredity; rather, it refers to a type of logical fallacy in which an argument is evaluated on the basis of where it comes from. Generally, arguments stand or fall on their own merits and not on those of their sources.
The Genetic Fallacy is the most general fallacy of irrelevancy involving the origins or history of an idea. It is fallacious to either endorse or condemn an idea based on its pastrather than on its presentmerits or demerits, unless its history is in some way relevant to its present value. So, the Genetic Fallacy is committed whenever an idea is evaluated based upon irrelevant history.
To understand and apply this fallacy correctly, it's important to make three distinctions:
- Arguer/Argument: The arguer is the person who makes an argument; the argument is what the arguer says or writes. Evaluating the argument and evaluating the arguer are two distinct activities: the former is a question of logic, the latter of ethics. Of course, the two types of evaluation may be connected, but they use different standards. A person who makes fallacious arguments, especially habitually, may be a bad arguer or even a dishonest person, but even the worst arguers sometimes make good arguments. Similarly, sometimes even the best people make bad arguments.
- Testimony/Argument: The origin of testimonywhether first hand, hearsay, or rumorcarries weight in evaluating it. For example, the testimony of a liar should be given little credit, but whether an arguer is a liar, or in any other way a bad person, is irrelevant to whether the argument is valid, sound, or cogent. Similarly, even the most truthful and honest person may make a mistake in reasoning. So, if what a person says or writes is testimony, then facts about the person may be relevant to evaluating it; not so if it is an argument.
- Premisses/Reasoning: Every argument has two elements that require evaluation: its premisses and the reasoning that connects the premisses to its conclusion. The origin of claims contained in the premisses can be relevant to their evaluation, especially if they are historical claims. However, the origin of reasoning is irrelevant to its evaluation. The logical strength of reasoning is evaluated based on the formal, semantic, or probabilistic relations between the premisses and conclusion, and not on who made the argument or where it comes from.
- Since this fallacy is the most general one of irrelevance due to origin, arguments that commit it will usually be instances of one of its subfallacies―see above. For this reason, I do not provide an example; for an example, see one of the subfallacies.
- The value of many scientific ideas can be objectively evaluated by established techniques, so that the origin or history of the idea is irrelevant to its value. For example, the chemist Kekulé claimed to have discovered the ring structure of the benzene molecule during a dream of a snake biting its own tail. While this fact is psychologically interesting, it is neither evidence for nor against the hypothesis that benzene has a ring structure, which had to be tested for correctness. To offer Kekulé's dream as evidence either for or against the benzene ring hypothesis would be to commit the Genetic Fallacy.2