 It’s not about underdetermination. Gold’s negative results are sometimes wrongly taken to be an unsurprising reflection of the underdetermination of theories by finite bodies of evidence (Hauser et al. 2002 seem to make this erroneous equation on p. 1577; so do Fodor and Crowther 2002, implicitly—see Scholz and Pullum 2002, 204–206). But the failure of text-identifiability for certain classes of languages is different from underdetermination in a very important way, because there are infinite classes of infinite languages that are identifiable from text. The first chapter of Jain et al. (1999) discusses an illustrative example (basically, it is the class containing, for all n &gt; 0, the set of all strings with length greater than n). There are infinitely many others. For example, Shinohara (1990) showed that for any positive integer n the class of all languages generated by a context-sensitive grammar with not more than n rules is learnable from text.