When one makes a generalization on something, and there are only two examples in which said event has occurred.
Person 1: "Yeah, that person always sings".

Person 2: "He's only sang at your birthday, and at the store. Two theory".
by two theorizer April 4, 2010
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The theory that ignorant people will wait excessive amounts of time to walk through an open door, as opposed to opening another door and saving themselves a great deal of time.
These people clearly never heard of the two-door theory
by Street Urchin April 6, 2004
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