Under-Reporting the Facts
(Suppressed Evidence)

Description:

The argument proposes an explanation (usually somewhat arcane) for a fact that appears surprising or mysterious only because not all of the relevant accompanying facts have been reported. The additional facts suggest a different (and usually perfectly ordinary) explanation.

Examples:

"An unusually large number of ships are lost in the Bermuda Triangle as compared to other areas of the ocean. There is clearly something mysterious about the place!" [In fact, a large number of busy shipping lanes intersect in the Bermuda Triangle. Hence the number of ships passing through that region of the ocean is unusually high. The number of ships lost there, as a percentage of the ships that pass through there, is not in fact different than in other areas of the ocean.]

"This statue of the Virgin Mary is truly possessed by her spirt. Often the statue weeps for the suffering of humanity." [The statue stands in a grotto where water seepage creates humid conditions. The "weeping" occurs on cool mornings when normal condensation is to be expected.]

"There is what seems to be a clear human footprint on top of a dinosaur footprint in an ancient streambed in Texas. The best explanation for this is that humans and dinosaurs existed at the same time." [The presumed human footprint appears in the Paluxy River formation. The print is actually from a dinosaur that leaves a partial footprint similar to the heel of a human foot. Where the entire footprint is preserved (further along the same track) it can be seen to have three bird-like toes with sharp claws--clearly not human.]

Discussion:

This fallacy mimics good reasoning in the most direct possible way: it draws on facts that are actually true, and do in fact require an explanation. Where the explanation is arcane, we might consider it an instance of Arcane Explanation. Where the explanation is not exceptionally arcane, it must necessarily pass as good reasoning. We cannot expose the fallacy for the fallacy that it is except by being aware of the additional facts (also true) that have not been revealed. Since the exercises for a logic class are generally designed to be done without outside checking, there will be no exercises for this fallacy. However, again, it is important to realize that this is a frequently occurring fallacy: a great deal of pseudo-science is supported by it.

Source: John Stuart Mill describes this fallacy in A System of Logic, 1843, under the heading "fallacies of observation." The name given here is my own invention.

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