The twentieth century saw a series of closely related and inextricably intertwined methodological debates about the problem of the empiricalness of linguistic theories. From the second part of the nineties, the methodological debates on data and evidence were gradually extended both at an object- and at a meta-theoretical level, and were enriched with new elements. Today they affect several different research fields and branches of linguistics. The contemporary discussion no longer centres on the problem of whether linguistic theories should be empirical or not. Rather, the following questions are focused on: What types of data may be used, what data count as evidence, and what role can be attributed to them in different fields of linguistic theorising? The aim of the present paper is the systematization and the critical analysis of current answers to these questions. From the findings of the analyses conclusions will be drawn that are expected to pave the way for the future solution of the problems raised in the discussion at issue.