Post hoc

The Post hoc fallacy is a logical fallacy which assumes, or asserts, that if one thing happens after another, the first must be the cause of the second. It's a particularly subtle, and tempting, error because temporal sequence is basic to causality.

Post hoc is from the Latin for "after that"; the long form of the phrase is post hoc ergo propter hoc, "after that, therefore because of that."

A non-controversial example is "I just washed my car; of course it is going to rain." Rain is not caused by car-washing, but the car owner connects the two events. The person down the street did not wash her car, and it is raining on her too.

Post hoc reasoning is related to magical thinking, connecting two things that have no actual or logical connection, as well as correlation implies causation.