Post hoc ergo propter hoc

Post hoc ergo propter hoc (<a href="/facts/Latin/pM3Kge85">Latin</a>: 'after this, therefore because of this') is an <a href="/facts/Informal_fallacy/MfICjFRF">informal fallacy</a> 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 <a href="/facts/Logical_fallacy/1c3P1BEH">logical fallacy</a> of the <a href="/facts/Questionable_cause/8HA55aht">questionable cause</a> variety, it is subtly different from the fallacy <a href="/facts/Correlation_does_not_imply_causation/IeWeoMB9">cum hoc ergo propter hoc</a> ('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.
Post hoc is a particularly tempting error because correlation sometimes appears to suggest <a href="/facts/Causality/Swh496X7">causality</a>. 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.
A simple example is "The <a href="/facts/Chicken/RD2eTd83">rooster crows</a> immediately before <a href="/facts/Sunrise/hMAQ2oh2">sunrise</a>; therefore the rooster causes the sun to rise."

Post hoc ergo propter hoc open-in-new

Post hoc ergo propter hoc