Editing Michael Halliday (section)

=== Fundamental categories ===
Halliday's first major work on grammar was "Categories of the Theory of Grammar", in the journal ''Word'' in 1961.<ref name="Halliday, M.A.K 1961. pp. 241"/> In this paper, he argued for four "fundamental categories" in grammar: ''unit'', ''structure'', ''class'', and ''system''. These categories are "of the highest order of abstraction", but he defended them as necessary to "make possible a coherent account of what grammar is and of its place in language"<ref>Halliday, 1961 "Categories of the theory of grammar". ''Word'' 17(3); in Halliday, 2002. ''On Grammar'', Vol. 1 in ''The Collected Works'', p. 41.</ref> In articulating unit, Halliday proposed the notion of a ''[[rank scale]]''. The units of grammar form a hierarchy, a scale from largest to smallest, which he proposed as a ''sentence'', ''clause'', ''group/phrase'', ''word,'' and ''morpheme''.<ref>Halliday, 1961, "Categories of the theory of grammar". ''Word'' 17(3); in Halliday, 2002. ''On Grammar''. Vol. 1 in the ''Collected Works'', p. 45.</ref> Halliday defined structure as "likeness between events in successivity" and as "an arrangement of elements ordered in places".<ref>Halliday, 1961 "Categories of the theory of grammar". ''Word'' 17(3); in Halliday, 2002. ''On Grammar''. Vol. 1 in ''The Collected Works'', p. 46.</ref> He rejects a view of the structure as "strings of classes, such as nominal group + verbalgroup + nominal group", describing structure instead as "configurations of functions, where the solidarity is organic".<ref>Halliday, M.A.K. 2005, ''Studies in English Language'', Introduction. Vol. 7 in ''The Collected Works'', p. xvii.</ref>