Martin's notion of 'commitment' is invalidated by the fact that it is based on a fundamental misunderstanding of the system network, namely: that a speaker can choose the degree of delicacy to be instantiated during logogenenesis. As Martin (2011: 255-6) explains:
Instantiation also opens up theoretical and descriptive space for considering commitment (Martin 2008, 2010), which refers to the amount of meaning instantiated as the text unfolds. This depends on the number of optional systems taken up and the degree of delicacy pursued in those that are, so that the more systems entered, and the more options chosen, the greater the semantic weight of a text (Hood 2008).
To be clear, a system network is not a type of flowchart, such that instantiation involves a movement through more and more delicate systems. A system network is a network of relations. In the case of lexicogrammar, the system specifies how all the features are related to each other, such that the instantiation of each lexical item in a text is the instantiation of all the features that specify it, from the most general all the way to the most delicate.
