This study reconsiders the place and nature of the logical metafunction in systemic theory. Halliday considers logical and experiential as subparts of the ideational metafunction, which he differentiates from the interpersonal and the textual, and he relates specific parts of the lexicogrammar to each metafunction, and each metafunction to a parameter of the context of situation. Here the proposal is to consider the logical component as an added function available for combination with each of the other three, and related equally to each of these, as well as to the field, tenor and mode of the context of situation. Logical meaning is considered independently from the strict structural constraints of recursion, parataxis and hypotaxis. Both projection and expansion are seen as multifunctional and as occurring at all grammatical ranks and at text level. Logical meaning is also seen in relational and existential processes, and as an extra unifying element in systems perceived as overlapping (modality and modulation, comparison and intensification).