Post hoc ergo propter hoc
Encyclopedia
Post hoc ergo propter hoc, Latin
for "after this, therefore because of this," is a logical fallacy (of the questionable cause
variety) that states, "Since that event followed this one, that event must have been caused by this one." It is often shortened to simply post hoc and is also sometimes referred to as false cause, coincidental correlation, or correlation not causation. It is subtly different from the fallacy cum hoc ergo propter hoc
, in which the chronological ordering of a correlation is insignificant.
Post hoc is a particularly tempting error because temporal sequence appears to be integral to causality
. The fallacy lies in coming to a conclusion based solely on the order of events, rather than taking into account other factors that might rule out the connection.
When B is undesirable, this pattern is often extended in reverse: Avoiding A will prevent B.
by T. Edward Damer
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From With Good Reason by S. Morris Engel
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One class of examples is sometimes called the "Rooster Syndrome": "believing that the rooster’s crowing causes the sun to rise".
Latin
Latin is an Italic language originally spoken in Latium and Ancient Rome. It, along with most European languages, is a descendant of the ancient Proto-Indo-European language. Although it is considered a dead language, a number of scholars and members of the Christian clergy speak it fluently, and...
for "after this, therefore because of this," is a logical fallacy (of the questionable cause
Questionable cause
Fallacies of questionable cause, also known as causal fallacies, non causa pro causa or false cause, are informal fallacies where a cause is incorrectly identified...
variety) that states, "Since that event followed this one, that event must have been caused by this one." It is often shortened to simply post hoc and is also sometimes referred to as false cause, coincidental correlation, or correlation not causation. It is subtly different from the fallacy cum hoc ergo propter hoc
Correlation does not imply causation
"Correlation does not imply causation" is a phrase used in science and statistics to emphasize that correlation between two variables does not automatically imply that one causes the other "Correlation does not imply causation" (related to "ignoring a common cause" and questionable cause) is a...
, in which the chronological ordering of a correlation is insignificant.
Post hoc is a particularly tempting error because temporal sequence appears to be integral to causality
Causality
Causality is the relationship between an event and a second event , where the second event is understood as a consequence of the first....
. The fallacy lies in coming to a conclusion based solely on the order of events, rather than taking into account other factors that might rule out the connection.
Pattern
The form of the post hoc fallacy can be expressed as follows:- A occurred, then B occurred.
- Therefore, A caused B.
When B is undesirable, this pattern is often extended in reverse: Avoiding A will prevent B.
Examples
From Attacking Faulty ReasoningAttacking Faulty Reasoning
Attacking Faulty Reasoning is a textbook on logical fallacies by T. Edward Damer that has been used for many years in a number of college courses on logic, critical thinking, argumentation, and philosophy. It explains 60 of the most commonly committed logical fallacies. Each of the fallacies is...
by T. Edward Damer
T. Edward Damer
Biography=Dr. Damer is a professor of philosophy and chair of the Division Visual and Performing Arts at Emory and Henry College in Emory, Virginia. He has been on the Emory faculty since 1967. In 1991, he won the James A...
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From With Good Reason by S. Morris Engel
S. Morris Engel
S. Morris Engel is an author, philosopher, and linguist. He received his Ph.D. from the University of Toronto in 1959, writing on "The philosophy of language in Hobbes and Locke"...
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One class of examples is sometimes called the "Rooster Syndrome": "believing that the rooster’s crowing causes the sun to rise".
See also
- Confirmation biasConfirmation biasConfirmation bias is a tendency for people to favor information that confirms their preconceptions or hypotheses regardless of whether the information is true.David Perkins, a geneticist, coined the term "myside bias" referring to a preference for "my" side of an issue...
- Third-cause fallacyThird-cause fallacyThe third cause fallacy is a logical fallacy that asserts that X causes Y when, in reality, X and Y are both caused by Z. It is a variation on the post hoc ergo propter hoc fallacy and a member of the questionable cause group of fallacies....
- Regression fallacyRegression fallacyThe regression fallacy is an informal fallacy. It ascribes cause where none exists. The flaw is failing to account for natural fluctuations. It is frequently a special kind of the post hoc fallacy.-Explanation:...
- SuperstitionSuperstitionSuperstition is a belief in supernatural causality: that one event leads to the cause of another without any process in the physical world linking the two events....
- Magical thinkingMagical thinkingMagical thinking is causal reasoning that looks for correlation between acts or utterances and certain events. In religion, folk religion, and superstition, the correlation posited is between religious ritual, such as prayer, sacrifice, or the observance of a taboo, and an expected benefit or...
- Cargo cultCargo cultA cargo cult is a religious practice that has appeared in many traditional pre-industrial tribal societies in the wake of interaction with technologically advanced cultures. The cults focus on obtaining the material wealth of the advanced culture through magic and religious rituals and practices...
- Whig historyWhig historyWhig history is the approach to historiography which presents the past as an inevitable progression towards ever greater liberty and enlightenment, culminating in modern forms of liberal democracy and constitutional monarchy. In general, Whig historians stress the rise of constitutional government,...
External links
- http://www.experiment-resources.com/post-hoc-reasoning.html in the Experiment-resources.com by Martyn Shuttleworth
- Post hoc fallacy in the Skeptic's DictionarySkeptic's DictionaryThe Skeptic's Dictionary is a collection of cross-referenced skeptical essays by Robert Todd Carroll, published on his website skepdic.com and in a printed book. The skepdic.com site was launched in 1994 and the book was published in 2003 with nearly 400 entries. As of January 2011 the website has...
by Robert T. Carroll - Post Hoc, Ergo Propter Hoc in the Fallacy Files by Gary N. Curtis
- Non Causa Pro Causa in the Fallacy Files by Gary N. Curtis