Rule following Rules and practice in subject indexing

The importance attached to subject indexing in library services, librarian awareness of its social role and practical purposes, attention to indexing practices and the use of catalogs: How are these elements reflected in the system of rules governing subject indexing in Italy? What does "rule following", to use Wittengenstein's well-known expression, mean in our field? Why and how do we follow a rule? In which sense is following a rule a practice? How and in which conditions does the rule relate to the practice and vice versa? Beginning with these questions, the main features of the Italian subject indexing rules are illustrated: explicit rules, based on linguistic criteria, contain justifications for why a given rule should be followed and should be sensitive to the use-context. All three of these features imply a relationship with practice; at the same time, the rules presuppose a social practice in which they are employed and express their pragmatic meaning. Thus, the indexing rules are manifested in the language of indexing through the means by which this language is used; that is, in the indexing activity and in the use of catalogs. Hence, the call for libraries to attend to the pragmatic dimension of subject indexing.