One of the objections against the thesis of underdetermination of theories by observations is that it is unintelligible. Any two empirically equivalent theories — so the argument goes—are in principle intertranslatable, hence cannot count as rivals in any non-trivial sense. Against that objection, this paper shows that empirically equivalent theories may contain theoretical sentences that are not intertranslatable. Examples are drawn from a related discussion about incommensurability that shows that theoretical non-intertranslatability is possible.

Quine’s writings on indeterminacy of translation are mostly abstract and theoretical; his reasons for the thesis are not based on historical cases of translation but on general considerations about how language works. So it is no surprise that a common objection to the thesis asserts that it is not backed up by any positive empirical evidence. Ian Hacking (1981 and 2002) claims that whatever credibility the thesis does enjoy comes rather from alleged (fictitious) cases of radical mistranslation. This paper responds (...) to objections of that kind by exhibiting actual cases of indeterminacy of translation. (shrink)