Halliday (2008: 120, 121):
One problem that has sometimes been raised in this connection is that the number of options seems too vast. […] But (as Wimsatt pointed out, criticising Chomsky’s notion of the innateness of grammar — what he referred to as “generative entrenchment” and the “developmental lock”), what is relevant is the number of choice points; […] The system network is not a modelling of neural processes — it is an analytical tool for the grammarian. But there is nothing improbable in the range of possibilities that such networks are able to represent.