Donald Davidson, answered from the texts and cited to the page.
Radical interpretation is the project of working out what a speaker means and what a speaker believes simultaneously, from scratch, without prior access to either. The problem arises from a kind of symmetry that makes the interpreter's situation look hopeless at first. What the interpreter can observe — the circumstances under which a speaker holds sentences true — is the product of two things the interpreter does not yet know: meaning and belief.1
If you knew the meanings, you could read off the beliefs; if you knew the beliefs expressed by sentences held true, you could read off the meanings. But you cannot get either first, because each depends on the other.2 The evidential base I propose for breaking into this circle is the attitude of holding true, relativized to time and to observable external circumstances.3
A speaker holds 'Es schneit' true when and only when it is snowing — that is the kind of datum available. We can, I claim, identify when a speaker holds a sentence true without already knowing what the sentence means or what beliefs the speaker has about its subject matter.4 This is not obvious, but it is defensible: even the compulsive liar can be found out, so the independence of the evidential base from semantic knowledge does not require that speakers be generally sincere.5
Why not simply begin with a prior inventory of the speaker's beliefs and intentions, and build the meaning theory on top of that? Because there is a principled obstacle, not merely a practical one. Making detailed sense of a person's sophisticated beliefs and intentions cannot be done independently of making sense of his utterances.6 We have no good idea how to authenticate the existence of such attitudes when communication is not yet possible.
The inventory of beliefs cannot therefore serve as the evidence for the meaning theory; it is part of what the meaning theory is supposed to deliver.7 What makes interpretation possible at all, given this circularity, is the Principle of Charity. The interpreter must read his own standards of truth and logical consistency into the pattern of sentences held true by the speaker.8
Too great a deviation from consistency and correctness leaves no common ground on which to judge either conformity or difference; without charity, no stable target for interpretation emerges. Formally, charity restrains the degrees of freedom allowed to belief while the interpreter determines how to assign truth conditions to words.9 The target of the whole exercise is a Tarski-style characterization of truth for the speaker's language, from which a theory of the speaker's beliefs follows — since beliefs can be read off once meanings are fixed and the sentences held true are known.10
The pattern of sentences held true gives sentences their meaning in the same way that the pattern of belief allows us to identify any individual thought: it is the pattern, not any single datum, that carries the interpretive weight.11 Radical interpretation is not an idealized description of what linguists actually do. It is a way of asking what must be true for interpretation to be possible at all — a constitutive inquiry.
What a fully informed interpreter could learn about what a speaker means is all there is to learn; the same goes for what the speaker believes.12
The interpreter's problem is that what he is assumed to know—the causes of assents to sentences of a speaker—is, as we have seen, the product of two things he is assumed not to know, meaning and belief.Subjective, Intersubjective, Objective, pp. 167–168
If he knew the meanings he would know the beliefs, and if he knew the beliefs expressed by sentences assented to, he would know the meanings. But how can he learn both at once, since each depends on the other?Subjective, Intersubjective, Objective, pp. 167–168
Instead of utterances of expressions, I want to consider a certain attitude towards expressions, an attitude that may or may not be evinced in actual utterances. The attitude is that of holding true, relativized to time.Inquiries into Truth and Interpretation, pp. 144–145
I hope it will be granted that it is plausible to say we can tell when a speaker holds a sentence to be true without knowing what he means by the sentence, or what beliefs he holds about its unknown subject matter.Inquiries into Truth and Interpretation, pp. 144–145
even the compulsive liar and the perennial kidder may be found out.Inquiries into Truth and Interpretation, pp. 144–145
making detailed sense of a person's intentions and beliefs cannot be independent of making sense of his utterances.Inquiries into Truth and Interpretation, pp. 143–144
an inventory of a speaker's sophisticated beliefs and intentions cannot be the evidence for the truth of a theory for interpreting his speech behaviour.Inquiries into Truth and Interpretation, pp. 143–144
the principle directs the interpreter to translate or interpret so as to read some of his own standards of truth into the pattern of sentences held true by the speaker.Subjective, Intersubjective, Objective, pp. 167–168
From a formal point of view, the principle of charity helps solve the problem of the interaction of meaning and belief by restraining the degrees of freedom allowed belief while determining how to interpret words.Subjective, Intersubjective, Objective, pp. 167–168
Radical interpretation...aims at producing a Tarski-style characterization of truth for the speaker's language, and a theory of his beliefs. (The second follows from the first plus the presupposed knowledge of sentences held true.)Subjective, Intersubjective, Objective, pp. 167–168
it is the pattern of sentences held true that gives sentences their meaning.Inquiries into Truth and Interpretation, p. 162
What a fully informed interpreter could learn about what a speaker means is all there is to learn; the same goes for what the speaker believes.Subjective, Intersubjective, Objective, pp. 167–168