The aim of this paper is to discuss the principal theoretical and methodological questions that emerge from William Labov's recent Principles of Linguistic Change. Vol. II Social Factors, which nowadays constitutes the main heuristic and hermeneutic proposal about variation and change as interconnected phenomena. Problems regarding stable variables, change in progress, and other related issues are discussed here. Such questions are relevant not only to sociolinguistics but to historical and general linguistics as well.