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Cum Hoc, Ergo Propter Hoc

November 8th, 2009

Taxonomy – Where am I?

Cum Hoc, Ergo Propter Hoc

classification : informal – non causa pro causa

With this, therefore because of this.
Committed when one jumps to a conclusion about causation based on a correlation between two events, or types of event, which occur simultaneously.


The fallacy is to assert that because two events occur together, they must be causally related. It’s a fallacy because it ignores other factors that may be the cause(s) of the events.


Changing lanes in my car causes the rest of the traffic to speed up or slow down.

Other Names

Correlation does not imply causation
Post hoc ergo propter hoc (coincidental correlation)
Spurious relationship
Chain reaction
Domino effect

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Categories: Logic