12 Stanley E. Porter and Matthew Brook O’Donnell ὡς οὕτως ὅπου ὅθεν οὗ ὅτε ἕως πρίν ἄχρι οὔπω εἰ ὅτι ἄρα ἐπεί ἵνα ὅπως ὥστε μήπω Comparison is the least specified and most assimilative of logical-se- mantic relations, whereas purpose and result provides the greatest degree of motivation for action. The other types of procedural logical-semantic relations are organized within these parameters. Thus spatial and tempo- ral locations are seen as most closely related to comparison, as they are indicating positions within which actions occur. Conditionality intro- duces the circumstances under which something might occur, and then causality and purpose indicate reasons and motivations. Comparison is the least marked of the logical-semantic relations and purpose the most marked, as it indicates the motivation that has prompted the action. 4. Systemic-Functional Network of Conjunctions In a given context we must assume that a given author selected26 the appropriate conjunction in the light of a variety of factors. A systemic- functional network may well help us to understand how these several factors form a network of conjunctive system-choices27. The single entry condition of “conjunction” has two simultaneous sub-systems. One is the level of discourse that the writer or speaker wishes to join together. The entry condition for such a system within the network would be differentiation of the unit to be conjoined (e.g. DISCOURSE LEVEL), the vertical level. This may involve joining words, word groups, clauses, clause complexes or even paragraphs together. The restricted distribu- tion of conjunctions on the vertical axis requires that the author select a conjunction that functions at the level that is being conjoined. The Greek repertoire of available choices is complex even at this level, as a number of conjunctions function at multiple levels of conjunction, while others are more restricted in their nature. The second sub-system for choice of conjunctions is the type of conjoining (e.g. CONJUNCTIVE TYPE)– whether one wishes to conjoin in terms of “continuity-discontinuity” or We use the term “selected” in the sense in which the term is used in systemic-func- 26 tional linguistics, as a means of differentiating choice within systems, not that such choice is always or necessarily conscious. The most sophisticated conjunction system we have found is that in M.A.K. Halliday 27 and C.M.I.M. Matthiessen, An Introduction to Functional Grammar (London 32004) 541. However, this is a relatively simple system compared to ours, with a single input condition, “conjuncted”, that does not take the level of discourse into account.