truth-value most narrowly, one of the values T (for ‘true’) or F (for ‘false’) that a proposition may be considered to have or take on when it is regarded as true or false, respectively. More broadly, a truth-value is any one of a range of values that a proposition may be considered to have when taken to have one of a range of different cognitive or epistemic statuses. For example, some philosophers speak of the truth-value I (for ‘indeterminate’) and regard a proposition as having the value I when it is indeterminate whether the proposition is true or false. Logical systems employing a specific number n of truthvalues are said to be n-valued logical systems; the simplest sort of useful logical system has two truth-values, T and F, and accordingly is said to be two-valued. Truth-functions are functions that take truth-values as arguments and that yield truth-values as resultant values. The truthtable method in propositional logic exploits the idea of truth-functions by using tabular displays. See also TRUTH TABLE. R.W.B.