In order to define the contension measure we need to consider three-valued interpretations for propositional logic [Priest:1979]. A three-valued interpretation on is a function where the values and correspond to the classical truth values and , respectively. The additional truth value stands for both and is meant to represent a conflicting truth value for a proposition. The function is extended to arbitrary formulas as shown in the following table

Then, an interpretation satisfies a formula , denoted by if either or . The contension inconsistency measure is defined as

The contension inconsistency measure has been discussed in e.g. [Grant:2011].