Halliday & Matthiessen (1999: 423):
Jackendoff (1983: Ch. 2), working within cognitive semantics, argues that the account of 'aboutness' in formal semantics is simplistic:
... I will take issue with the naive (and nearly universally accepted) answer that the information language conveys is about the real world, (p. 24) ... If indeed the world as experienced owes so much to mental processes of organisation, it is crucial for a psychological theory to distinguish carefully between the source of environmental input and the world as experienced. For convenience, I will call the former the real world and the latter the projected world (experience world or phenomenal world would also be appropriate), (p. 28) ...It should now be clear why we must take issue with the naive position that the information conveyed by language is about the real world. We have conscious access only to the projected world — the world as unconsciously organised by the mind; and we can talk about things only insofar as they have achieved mental representation through these processes of organisation. Hence the information conveyed by language must be about the projected world. We must explain the naive position as a consequence of our being constituted to treat the projected world as reality.According to this view, the real world plays only an indirect role in language: it serves as one kind of fodder for the organising processes that give rise to the projected world. If this is the case, we must question the centrality to natural language semantics of the notions of truth and reference as traditionally conceived. Truth is generally regarded as a relationship between a certain subset of sentences (the true ones) and the real world; reference is regarded as a relationship between expressions in a language and things in the real world that these expressions refer to. Having rejected the direct connection of the real world to language, we should not take these notions as starting points for a theory of meaning. Thus an approach such as that of Davidson (1970), which attempts to explicate natural language semantics in terms of Tarskian recursive theory of truth, is antithetical to our own inquiry, (pp. 29-30)
The projected world in Jackendoff's account is the result of creative acts of perception: it is constructed as a model of sensory input, but with the significant addition of information from the perceptual system itself.