Michael Halliday on Philosophy

"First, it is transmitted physically, by sound waves traveling through the air; secondly, it is produced and received biologically, by the human brain and its associated organs of speech and hearing; thirdly it is exchanged socially, in contexts set up and defined by the social structure; and fourthly it is organized semiotically as a system of meanings"

"Any text in spoken English is organized into what may be called 'information units'. this is not determined by constituent structure. Rather could it be said that the distribution of information specifies a distinct structure on a different plan. Information structure is realized phonologically by 'tonality', the distribution of the text into tone groups."

"We should not, perhaps, take it for granted that a description in terms of a formalised model, which has certain properties lacking in those derived from models of another kind, will necessarily be the best description for all of the very diverse purposes for which the descriptions of languages are needed. In assessing the value of a description, it is reasonable to ask whether it has proved useful for the purposes for which it was intended."

"A physical system is just that: a physical system. What is systematized is matter itself, and the processes in which the system is realized are also material. But a biological system is more complex: it is both biological and physical — it is matter with the added component of life; and a social system is more complex still: it is physical, and biological, with the added component of social order, or value. … A semiotic system is still one step further in complexity: it is physical, and biological, and social —and also semiotic: what is being systematized is meaning. In evolutionary terms, it is a system of the fourth order of complexity"