View source for Post hoc ergo propter hoc

'''Post hoc ergo propter hoc''' ([[Latin]] for "after this; therefore, because of this") is a [[logical fallacy]] used to assume that two sequential events must have a cause-and-effect relationship. It is a subset of the [[Logical fallacy#False cause|fallacy of false cause]].

[[Liberal]]s use this fallacy frequently.  For example, they use the fact that [[Barack Hussein Obama]] was elected, and then the economy allegedly started to recover to show that Obama's election caused the economy to recover, which is complete nonsense. Another ridiculous example that they use is good things that supposedly happen in societies that have embraced [[homosexuality]]. Liberals use the fallacy to call for expanded government: If ''X'' happened, and then undesirable event ''Y'' happened, they argue that ''X'' must be banned to prevent future occurrences of ''Y.''

A variation holds that if ''X'' happened and then ''Y'' did not happen, ''X'' must have prevented ''Y.'' Those disputing a causal relationship sometimes refer to ''X'' as an '''anti-tiger rock''', after the joke that a certain rock must have the magical ability to repel tigers because there are no tigers around. Liberals often justify their favored laws on the basis of what bad things have not happened, without presenting evidence or argument that those things would have happened otherwise.

An inversion holds that if ''X'' happened and then ''Y'' did not happen, ''X'' was unnecessary to prevent ''Y'' because ''Y'' would not have happened regardless. Both this inversion and the regular version of the fallacy are fallacious because they ignore the difference between causation and coincidence. 
==See also==
*[[Affirming the consequent]]
[[Category:Logical Fallacies]]