====== Disjunction (logic) ======

A logical [[glossary:proposition|proposition]] of the form "A //or// B". The term can refer to either an //inclusive// or an //exclusive// "or".

We therefore distinguish between two different types of disjunctions, for which the same word ("or") is used in English: 

===== Adjunction (inclusive “or”) =====

The following question is an example of an //inclusive// disjunction: 
> Would you like sugar //or// milk in your coffee?

This usually means: sugar, or milk, //or both//, i.e. it uses an //inclusive// "or". This is also referred to as an <strong maniculus "see:">[[glossary:adjunction|adjunction]]</strong>.

<aside info>**Note:** The term "disjunction" is also sometimes used more specifically to refer to an //inclusive// disjunction, i.e. an //adjuction//. Since this can lead to misunderstandings, we advise against using it in this meaning.</aside>

===== Contravalence (exclusive “or”) =====

 The situation is different with the following question:
> “Would you like ice cream or fruit salad for dessert?”

This usually means you can have //either// ice cream //or// fruit salad, //but not both//, i.e. this question uses an //exclusive// “or”, also known as “[[glossary:contravalence|contravalence]]”. 

===== See also =====

  * [[glossary:adjunction|Adjunction]] – //inclusive// disjunction: A //or// B (or both)
  * [[glossary:contravalence|Contravalence]] – //exclusive// disjunction: A //or// B (but not both)

  * [[logic:formal_fallacies:affirming_a_disjunct|Affirming a disjunct]] – logical fallacy
  * [[glossary:conjunction|Conjunction]] – proposition of the form "A //and// B"

===== More information =====

  * [[https://en.wikipedia.org/wiki/Logical_disjunction|Logical disjunction]] on //Wikipedia//

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