The doctrine due to Quine that no empirical evidence relevant to interpreting a speaker's utterances can decide among alternative and incompatible ways of assigning referents to the words used; hence there is no fact that the words have one reference or another. Although the doctrine is similar to that of the indeterminacy of translation, they are not identical. First, inscrutability of reference might be compatible with the different interpretations of the speaker all sharing the same truth-value, whereas indeterminacy is often supposed by Quine to require that the different interpretations stand in no kind of equivalence, so that on one interpretation what is said might be true, and on another false. Secondly, translation might be indeterminate even though reference is scrutable, if, for instance, it is a goal of correct translation to fix more than the references of terms. However ‘inscrutability’ is not quite the right term for Quine's doctrine, since the term implies something real but unknowable, whereas it is Quine's position that terms have no real unique reference. In the late book Pursuit of Truth (1990) Quine prefers the title ‘indeterminacy of reference’. See also indeterminacy of translation, proxy function.