Halliday & Matthiessen (1999: 521):
Probably some such system of logical relationships between processes will be found in all languages, though as always there is great variation in the formal resources that ace deployed, and also in the systematic semantic organisation of the relationships themselves. In English, and many other languages, the grammar makes a systematic distinction in the relative status that is accorded to the two processes entering into such a logical nexus. Either the two are construed as being equal in status, or one is construed as being dependent on the other. In principle, any particular type of expansion or projection can be interpreted in either way, either as "paratactic" or as "hypotactic";