Now we can take this a step further by considering the two directions of elaborating figures of identity: encoding and decoding.
As you remember from Halliday and Matthiessen (2004: 230), in the identifying clauses that construe these figures:
either the Value is encoded or the Token is decoded.
What varies is which participant functions as the Identifier and which functions as the Identified.
In an encoding clause, the Token conflates with the Identifier and the Value with the Identified.
As Halliday & Matthiessen (2004: 230) put it: ‘The identity encodes the Value by reference to the Token’.
So in these two examples, we can say:
The identity encodes the content by reference to the expression.
and
The identity encodes the signified by reference to the signifier.
Contrariwise, in a decoding clause, the Token conflates with the Identified and the Value with the Identifier.
In this case, again quoting Halliday & Matthiessen (2004: 230): ‘The identity decodes the Token by reference to the Value’
So in these two examples, we can say:
The identity decodes the expression by reference to the content.
and
The identity decodes the signifier by reference to the signified.
With these distinctions in mind, we are now in a position to construe perceptual categorisation as the encoding and decoding of experience.