For the mathematical term involving systems of linear equations, see Overdetermined system.
Overdetermination occurs when a single-observed effect is determined by multiple causes, any one of which alone would be sufficient to account for ("determine") the effect. That is, there are more causes present than are necessary to cause the effect. In the philosophy of science, this means that more evidence is available than is necessary to justify a conclusion. Overdetermination is in contrast to underdetermination, when the number or strength of causes is insufficient.
The term "overdetermination" (German: Überdeterminierung) was also used by Sigmund Freud as a key concept in his psychoanalysis