Semiotic Systems and the Categorisable
Semiotic systems are both a means of modelling the categorisable and a domain within what is being modelled. That is, a semiotic system can both model semiosis and be a participant in that modelling. To model the categorisable semiotically includes, reflexively, modelling the semiotic system itself.
For example, a semiotic model of the categorisable may distinguish between two domains: the material and the semiotic. In this case, the material is construed as that which is categorisable independent of semiosis, while the semiotic is construed as that which arises through the functioning of semiotic systems — as patterned potential for meaning.
Such a model is itself a semiotic categorisation. It is not a mirror of reality, but a way of construing experience as meaning.