Fallacies - 2

Alias: Post Hoc, Ergo Propter Hoc

Translation: After this, therefore because of this, Latin

Type: Non Causa Pro Causa

Forms
Event C happened immediately prior to event E. Therefore, C caused E.	Events of type C happen immediately prior to events of type E. Therefore, events of type C cause events of type E.
Examples
The only policy that effectively reduces public shootings is right-to-carry laws. Allowing citizens to carry concealed handguns reduces violent crime. In the 31 states that have passed right-to-carry laws since the mid-1980s, the number of multiple-victim public shootings and other violent crimes has dropped dramatically. Murders fell by 7.65%, rapes by 5.2%, aggravated assaults by 7%, and robberies by 3%.	…[E]vidence shows that even state and local handgun control laws work. For example, in 1974 Massachusetts passed the Bartley-Fox Law, which requires a special license to carry a handgun outside the home or business. The law is supported by a mandatory prison sentence. Studies by Glenn Pierce and William Bowers of Northeastern University documented that after the law was passed handgun homicides in Massachusetts fell 50% and the number of armed robberies dropped 35%.
Source: "The Media Campaign Against Gun Ownership", The Phyllis Schlafly Report, Vol. 33, No. 11, June 2000.	Source: "Fact Card", Handgun Control, Inc.

Analysis of the Examples

Counter-Example:

Roosters crow just before the sun rises.
Therefore, roosters crowing cause the sun to rise.

Exposition:

The Post Hoc Fallacy is committed whenever one reasons to a causal conclusion based solely on the supposed cause preceding its "effect". Of course, it is a necessary condition of causation that the cause precede the effect, but it is not a sufficient condition. Thus, post hoc evidence may suggest the hypothesis of a causal relationship, which then requires further testing, but it is never sufficient evidence on its own.

Exposure:

Post Hoc also manifests itself as a bias towards jumping to conclusions based upon coincidences. Superstition and magical thinking include Post Hoc thinking; for instance, when a sick person is treated by a witch doctor, or a faith healer, and becomes better afterward, superstitious people conclude that the spell or prayer was effective. Since most illnesses will go away on their own eventually, any treatment will seem effective by Post Hoc thinking. This is why it is so important to test proposed remedies carefully, rather than jumping to conclusions based upon anecdotal evidence.

Sibling Fallacy: Cum Hoc, Ergo Propter Hoc

Source:

T. Edward Damer, Attacking Faulty Reasoning: A Practical Guide to Fallacy-Free Arguments (Third Edition) (Wadsworth, 1995), pp. 131-132.

Resources:

• Julian Baggini, "Post Hoc Fallacies", Bad Moves.
• Robert Todd Carroll, "Post Hoc Fallacy", Skeptic's Dictionary.