In these books, Quine considers the methods available to a field linguist attempting to translate a hitherto unknown language. He notes that there are always different ways one might break a sentence into words, and different ways to distribute functions among words. Any hypothesis of translation could be defended only by appeal to context, by determining what other sentences a native would utter. But the same indeterminacy will appear there: any hypothesis can be defended if one adopts enough compensatory hypotheses about other parts of the language.
Consider Quine's example of the word "gavagai" uttered by a native upon seeing a rabbit. The linguist could do what seems natural and translate this as "Lo, a rabbit." But other translations would be compatible with all the evidence he has: "Lo, food"; "Let's go hunting"; "There will be a storm tonight" (these natives may be superstitious); "Lo, a momentary rabbit-stage"; "Lo, an undetached rabbit-part." Some of these might become less likely – that is, become more unwieldy hypotheses – in the light of subsequent observation. Others can only be ruled out by querying the natives: An affirmative answer to "Is this the same gavagai as that earlier one?" will rule out "momentary rabbit stage," and so forth. But these questions can only be asked once the linguist has mastered much of the natives' grammar and abstract vocabulary; that in turn can only be done on the basis of hypotheses derived from simpler, observation-connected bits of language; and those sentences, on their own, admit of multiple interpretations, as we have seen.
Indeterminacy of translation also applies to the interpretation of speakers of one's own language, and even to one's past utterances. This does not lead to skepticism about meaning – either that meaning is hidden and unknowable, or that words are meaningless. However, when combined with a (more or less behaviouristic) premise that everything that can be learned about the meaning of a speaker's utterances can be learned from his behaviour, the indeterminacy of translation does imply that there are no such entities as "meanings", since the notion of synonymy has no operational definition. But saying that there are no "meanings" is not to say that words are not meaningful or significant.
Quine denies an absolute standard of right and wrong in translating one language into another; rather, he adopts a pragmatic stance toward translation. A translation can be (in)consistent with the behavioural evidence. And while Quine does admit the existence of standards for good and bad translations, such standards are peripheral to his philosophical concern with the act of translation, hinging upon such pragmatic issues as speed of translation, and the lucidity and concision of the results. The key point is that more than one translation meets these criteria, and hence that no unique meaning can be assigned to words and sentences.