Why is the anecdotal fallacy a fallacy?

I want to know why personal testimony is important in a court of law but in a debate it is considered invalid?

And why is the claim of seeing a spirit met with far more skepticism than the claim of seeing a murder?

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    See Anecdotal evidence. Not clear your concern: personal testimony is obviously useful in court, where we have to find support for a specific fact (like e.g. person X having killed person Y). Apr 16, 2019 at 9:00
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    But that context is very different from that of scientific investigation : in science we are searching for laws, etc. and thus the individual claim about a "new fact" that is unsopported by experimental and repeteable (i.e. intersubjective) evidence is not a valid scientific cliam. Apr 16, 2019 at 9:01
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    A claim of seeing spirit is met with skepticism both in science and in a justice court. Apr 16, 2019 at 9:03
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    This is where free will comes in: one may choose whether or not to believe any particular personal testimony. Even in court, the credibility of the witness is an important factor, and is to be evaluated by the judge and jury.
    – Bread
    Apr 16, 2019 at 9:18
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    Eyewitness testimony is actually under a fair amount of scrutiny in in a court of law: en.wikipedia.org/wiki/Eyewitness_testimony
    – christo183
    Apr 16, 2019 at 9:42

1 Answer 1


Bo Bennett describes an "anecdotal fallacy" as an "argument from hearsay":

Presenting the testimony of a source that is not an eyewitness to the event in question. It has been conclusively demonstrated that with each passing of information, via analog transmission, the message content changes. Each small change can and often does lead to many more significant changes, as in the butterfly effect in chaos theory.

For an argument to be logically fallacious for Bennett it must be a commonly applied, deceptive error in reasoning. Not all anecdotal evidence would lead to a fallacious argument.

Wikipedia shows that anecdotal evidence can be important such as in case studies:

Anecdotal evidence is evidence from anecdotes, i.e., evidence collected in a casual or informal manner and relying heavily or entirely on personal testimony. When compared to other types of evidence, anecdotal evidence is generally regarded as limited in value due to a number of potential weaknesses, but may be considered within the scope of scientific method as some anecdotal evidence can be both empirical and verifiable, e.g. in the use of case studies in medicine. Other anecdotal evidence, however, does not qualify as scientific evidence, because its nature prevents it from being investigated by the scientific method.

Someone who is an eyewitness of either a spirit or a murder does not fall under the argument from hearsay definition. They are not a third party reporting the evidence in a casual or informal manner. They are the eyewitnesses.

Here is the final question:

And why is the claim of seeing a spirit met with far more skepticism than the claim of seeing a murder?

C. S. Lewis claims regarding miracles: (page 2)

What we learn from experience depends on the kind of philosophy we bring to experience.

Those who have more skepticism regarding seeing a spirit than witnessing a murder are expressing their philosophic view that seeing a spirit is more unlikely than witnessing a murder.

Bennett, B. "Argument from Hearsay". Retrieved from Logically Fallacious on April 16, 2019 at https://www.logicallyfallacious.com/tools/lp/Bo/LogicalFallacies/52/Argument-from-Hearsay

Lewis, C. S. (1947). Miracles; a preliminary study.

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