# Disjunction

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**Disjunction** is the combination of two sentences with *or*. In propositional logic, the disjunction of two formulas phi and psi, written phi v psi, is true if phi is true or psi is true or both, as is shown in the truth-table (i):

(i) phi psi phi v psi 1 1 1 1 0 1 0 1 1 0 0 0

This version of disjunction is called inclusive, because it allows the propositions phi and psi both to be true. Natural language *or* can also be used exclusively: only one of the two propositions may be true, but not both (*either ... or ...*).

### Link

Utrecht Lexicon of Linguistics

### References

- Gamut, L.T.F. 1991.
*Logic, language, and meaning,*Univ. of Chicago Press, Chicago.