From semantic deference to semantic externalism to a classification of disagreements to conceptual engineering

We distinguish three broad kinds of semantic externalism, which we assume are grounded in three types of semantic deference. Deference to usage (dispositional compliance with the norms of a common language practice) grounds ‘usage-dependent externalism’. Deference to the way current experts define words grounds ‘conventional externalism’. For ‘indexical externalism’, there is ultimate deference to the true nature of a phenomenon, yet ‘proximal’ deference to the people most likely to capture that nature.These distinctions prove fruitful when it comes to classifying disagreements between speakers. First, as the debates of the last 50 years have abundantly shown, there may be (conscious or not) metalinguistic disagreement as to what kind of semantic deference should be at work for the word. Second, even amongst those who agree on the kind of deference for a particular word, there may still be other kinds of disagreement. Within usage-dependent externalism, the extent of the relevant linguistic community remains open for discussion. Within conventional externalism, different speakers may still disagree on who are the experts responsible for fixing meaning. Within indexical externalism, there may be disagreement about who is most likely to capture the true nature of a phenomenon referred to, especially if that phenomenon is not (currently) studied by some specific scientific discipline.The classification just outlined furthermore suggests that the tasks conceptual engineers engage in and the objectives they pursue depend on the type of externalism that a term falls under.