Quine says, the function of science is to predict future experiences in the light of past ones, the only ground for choosing which explanations to believe is "the degree to which they expedite our dealings with sense experiences." While pragmatic concerns are important for Carnap and other logical positivists when choosing a linguistic framework, their pragmatism "leaves off at the imagined boundary between the analytic and the synthetic". For Quine, every change in the system of science is, when rational, pragmatic. Critique and influence Rudolf Carnap prepared a reply entitled "Quine on Analyticity", but this was not published until 1990. Addressing Quine's concern over the status of the sentence "Everything green is extended", Carnap wrote "the difficulty here lies in the unclarity of the word 'green', namely in an indecision over whether one should use the word for something unextended, i.e., for a single space-time point. In daily life it is never so used, and one scarcely ever speaks of space-time points." Carnap then puts forward that an exact artificial language ought to clarify the problem by defining 'green' (or its synonym) as something that is either necessarily or contingently not applied to space-time points. He wrote that once that decision is made, the difficulty is resolved. Carnap also answers Quine's argument on the use of sets of formal sentences to explain analyticity by arguing that this method is an explication of a poorly understood notion. Paul Grice and P. F. Strawson criticized "Two Dogmas" in their (1956) article "In Defense of a Dogma". Among other things, they argue that Quine's skepticism about synonyms leads to a skepticism about meaning. If statements can have meanings, then it would make sense to ask "What does it mean?". If it makes sense to ask "What does it mean?", then synonymy can be defined as follows: Two sentences are synonymous if and only if the true answer of the question "What does it mean?" asked of one of them is the true answer to the same question asked of the other. They also draw the conclusion that discussion about correct or incorrect translations would be impossible given Quine's argument. Four years after Grice and Strawson published their paper, Quine's book Word and Object was released. In the book Quine presented his theory of indeterminacy of translation. In "'Two Dogmas' revisited", Hilary Putnam argues that Quine is attacking two different notions. Analytic truth defined