Distances and Trees in Linguistics

I think it is important to keep in mind that the term "computational linguistics" is not parallel in content with many other terms in linguistics, such as "anthropological linguistics" or "psycholinguistics", or "phonology" or "pragmatics". These terms all refer to content aspects of language; these are, respectively, the role of language in various cultures, the relations between language and psychological mechanisms, how sounds pattern in language, and the use of language in different social contexts. In other words, they all deal with delimited, intrinsic aspects of language on which we are accumulating knowledge.