This study focuses on the diachronic development of the discourse marker after all in English. Unlike other approaches by Traugott (1997) or Lewis (2007), the present analysis suggests that the uses of after all are not contingent on conventionalization, whereby stable meaning-form pairings emerge. The alternative proposed here is that the justificative and concessive uses of this and similar expressions follow naturally from the meanings of the individual lexical items found in these expressions. Thanks to the intuitive connection between the original meaning and the newly acquired uses, this discourse marker does not require as much consolidation as in the case of grammaticalized forms where the connection is less obvious.