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Post hoc ergo propter hoc

{{short description|Fallacy of assumption of causality based on sequence of events}}

{{About|the informal fallacy|the West Wing episode|Post Hoc, Ergo Propter Hoc (The West Wing)||Post hoc (disambiguation){{!}}Post hoc}}{{Italic title}}

Post hoc ergo propter hoc (Latin: 'after this, therefore because of this') is an informal fallacy that states "Since event Y followed event X, event Y must have been caused by event X." It is a fallacy in which an event is presumed to have been caused by a closely preceding event merely on the grounds of temporal succession. This type of reasoning is fallacious because mere temporal succession does not establish a causal connection. It is often shortened simply to post hoc fallacy. A logical fallacy of the questionable cause variety, it is subtly different from the fallacy cum hoc ergo propter hoc ('with this, therefore because of this'), in which two events occur simultaneously or the chronological ordering is insignificant or unknown. Post hoc is a logical fallacy in which one event seems to be the cause of a later event because it occurred earlier.{{Cite journal|last=Grouse|first=Lawrence|title=Post hoc ergo propter hoc|journal=Journal of Thoracic Disease|year=2016|volume=8|issue=7|pages=E511–E512|doi=10.21037/jtd.2016.04.49|issn=2072-1439|pmc=4958779|pmid=27499984 |doi-access=free }}

Post hoc is a particularly tempting error because correlation sometimes appears to suggest causality. The fallacy lies in a conclusion based solely on the order of events, rather than taking into account other factors potentially responsible for the result that might rule out the connection.{{Cite web|title=post hoc|url=https://www.law.cornell.edu/wex/post_hoc|access-date=2021-08-28|website=LII / Legal Information Institute|language=en}}

A simple example is "The rooster crows immediately before sunrise; therefore the rooster causes the sun to rise."{{Cite web|date=2015-10-09|title=Correlation vs Causation|url=https://knowledgespace.com.au/correlation-vs-causation/|access-date=2021-08-28|website=KnowledgeSpace|language=en-US}}

Pattern

The form of the post hoc fallacy is expressed as follows:

:* A occurred, then B occurred.

:* Therefore, A caused B.

When B is undesirable, this pattern is often combined with the formal fallacy of denying the antecedent, assuming the logical inverse holds: believing that avoiding A will prevent B.{{cite journal |last1=Summers |first1=Jesse S. |title=Post hoc ergo propter hoc : some benefits of rationalization |journal=Philosophical Explorations |date=24 March 2017 |volume=20 |issue=sup1 |pages=21–36 |doi=10.1080/13869795.2017.1287292|s2cid=151401300 |doi-access=free }}

== Examples ==

  • A tenant moves into an apartment and the building's furnace develops a fault. The manager blames the tenant's arrival for the malfunction. One event merely followed the other, in the absence of causality.{{cite book |title= Attacking Faulty Reasoning: A Practical Guide to Fallacy-Free Arguments|last= Damer|first= T Edward|author-link= T. Edward Damer|edition= 3rd|year= 1995|publisher= Wadsworth Publishing|location= Belmont, CA|isbn= 978-0-534-21750-1|oclc= 30319422|page= 131}}
  • Brazilian footballer Pelé blamed a dip in his playing performance on having given a fan a specific playing shirt. His play recovered after receiving from a friend what he was told was the shirt in question, despite it actually being the same shirt he'd worn during his poor performance.{{Cite news|url=https://www.telegraph.co.uk/sport/football/teams/arsenal/4805924/Top-10-Football-superstitions-to-rival-Arsenals-Kolo-Toure.html|title=Top 10: Football superstitions to rival Arsenal's Kolo Toure|last=Macaskill|first=Sandy|date=2009-02-25|work=The Telegraph|archive-url=https://web.archive.org/web/20100826041515/https://www.telegraph.co.uk/sport/football/teams/arsenal/4805924/Top-10-Football-superstitions-to-rival-Arsenals-Kolo-Toure.html|archive-date=2010-08-26|url-status=live}}
  • Reporting of coincidental vaccine adverse events, where people have a health complaint after being vaccinated and assume it was caused by the vaccination.{{cite book|url=https://books.google.com/books?id=2Lmfug12yFkC&pg=PA119|title=Thinking and Reasoning: An Introduction to the Psychology of Reason, Judgment and Decision Making|last=Manktelow|first=K. I.|year=2012|publisher=Psychology Press|isbn=9781841697413|page=119}}

See also

  • {{annotated link|Apophenia}}
  • {{annotated link|Affirming the consequent}}
  • {{annotated link|Association fallacy}}
  • {{annotated link|Cargo cult}}
  • {{annotated link|Causal inference}}
  • {{annotated link|Coincidence}}
  • {{annotated link|Confirmation bias}}
  • {{annotated link|Correlation does not imply causation}}
  • {{annotated link|Jumping to conclusions}}
  • {{annotated link|Magical thinking}}
  • {{annotated link|Superstition}}
  • {{annotated link|Survivorship bias}}
  • {{annotated link|Surrogate endpoint}}
  • {{annotated link|Temporality}}
  • Texas sharpshooter fallacy

Bibliography

  1. Woods, J. H., Walton, D. N. (1977). Post Hoc, Ergo Propter Hoc.
  2. Mommsen, J. K. F. (2013). Wider Das Post Hoc Ergo Propter Hoc - Primary Source Edition. United States: BiblioLife.
  3. Woods, J., Walton, D. (2019). Fallacies: Selected Papers 1972–1982. Germany: De Gruyter.

References

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{{Fallacies}}

{{Time in philosophy}}

Category:Causal fallacies

Category:Latin logical phrases