The conditions of modelling the categorisable semiotically can be understood in terms of the metafunctional dimensions of meaning-making: the ideational, which includes the experiential and the logical, the interpersonal and the textual.
Firstly, models are located in the space of ideational variation. Models are organised through experiencing the categorisable.[1] Categorisable difference selects the categories that may or may not be organised into a model of the categorisable. So models depend on the recognition functionality of the neurological system and the prosthetic technologies that extend its recognition abilities, and they depend on the specific experience trajectories of modellers.
Secondly, models are located in the space of interpersonal variation. Models are organised by values that bias the orientation of modellers to different categories of experience. Limbic system functions that have been of adaptive value to ancestors invest the categories (that are selected by categorisable difference) with positive or negative value, and the complexification of categories within individuals — through the categorisation of categories and their differentiation through semiotic interactions with others — is the complexification of categorial values. Models are motivated organisations of categorisations.
Thirdly, models are located in the space of textual variation. Models are organised through selective attention to value-categories: focusing on some categories as relevant, and filtering out others as irrelevant.[2] Some value-categories are prominent threads in the weaving together of meanings, while others are thin or absent. Because modelling occurs through a perspectival lens, it is both enabling and disabling: a model is conditional on the assumptions on which it is organised.[3] Models are ‘ways of seeing’ (Berger 1972).
Footnotes:
[1] The ‘categorisable’ includes categorisations of the categorisable, categorisations of categorisations of the categorisable, and so on.
[2] This relates to Pike’s notion that a theory is like a window that only faces in one direction.
[3] The influence of ones perspectival lens on categorising was shown by a seminal psychology experiment by Rosenhan (reported in Slater 2004) in which subjects faking their way into mental institutions were not detected by most psychiatrists.