In Word and Object 1 Quine gives the following formulation of the thesis of the indeterminacy of translation: Manuals for translating one language into another can be set up in divergent ways, all compatible with the totality of speech dispositions, yet incompatible with one another. In countless places they will diverge in giving, as their respective translations of a sentence of the one language, sentences of the other language which stand to each other in no plausible sort of equivalence however loose. (WO, p. 27) He goes on to urge that this thesis can most clearly be seen to be true if we consider radical translation-translation where the linguist confronts native speakers without the benefit of even partially bilingual interpreters. (WO, p. 28)
Now it is a commonplace of contemporary philosophy of science that theories are underdetermined by data (that it is a commonplace is due in part to Quine's own efforts, of course). And it is tempting to see the indeterminacy of radical translation simply as an instance of this principle. 2 Consider what Quine's 'jungle linguist' has to do. He must first identify those acts by native speakers which are in fact linguistic. Then he must find criteria by which to group individual instances of speech acts into types. Next he must give a phonemic, syntactic and semantic analysis of these linguistic types. Finally, he must use a syntactic and semantic theory of his own 'home' language in setting up a translation manual between the two languages. At each of these steps the linguist must use a tentative theory, and at the syntactic and semantic stages especially we may except the theories used to be highly abstract. Thus on general epistemological principle, as noted above, Quine's thesis is prima faeie reasonable and straightforward, since radical translation seems just the kind of enterprise where we should expect a multiplicity of different theories. (This is especially so if we think of the 'native speakers' as nonhuman, for example robots from another planet or super-intelligent