The logical metafunction in systemic functional linguistics

Each step in a message must proceed by one of three principles of extension: (a) the simple adding of a structural element (parataxis, a linking between ‘equals’); (b) a link of dependency (hypotaxis, a subordination) between what emerges and what has gone before, or what may be coming next and (c) a sequence that is built by reiteration of the last structural selection (iteration, or recursion). The resources by which these three options are enacted throughout the structures of language, along with their systems of typical semantic motivation, can be thought of as the logical metafunction.