A model is a simplified representation of a
System.By defining models as being about
Systems, we
make a general but highly abstract
Ontological
Commitment to the actual existence of
Systems.
Representation means that a model is “about” or denotes its target system; more specifically, it “stands in” for the system in some functional context in some useful way.
In other words, representation is a product of function and
selection, either by design or by evolution:There are two interpretations of this relationship: On
the pragmatic account, models represent because of
their function as functional devices, on the informational
account it is the other way round. In an evolutionary account of
implicit models that interprets natural selection as “Bayesian model
selection over evolutionary time” (Kirchhoff et al. 2018, 4), the two
accounts become complementary descriptions of the underlying
evolutionary process.
- Explicit Models are consciously developed representations that can be objects of inspection, discussion and validation. They are built from Concepts and are thus systems of concepts.
- Implicit
Models are evolved, embodied representations of a system’s
Environment,
or more precisely of “statistical regularities of its world in its
physical and functional composition”Kirchhoff et al. (2018), 4
, and thus identical with the system itself (or part of it).
A model is useful for exploration, explanation or prediction (and thus gets selected) if it tracks salient features of the target system.
In this case, its simplifications can be understood as Abstractions of the target system’s structure and components.
An especially interesting case are Causal Models that track the Causal Structure of their target system.
If models track system boundaries, they represent real systems. If they don’t, they represent Missing Systems.
References
- Bailer-Jones (2009): Scientific Models in Philosophy of Science
- Frigg & Hartmann (2018): “Models in Science”
- Gelfert (2017): “The Ontology of Models”
- Kirchhoff et al. (2018): “The Markov blankets of life: autonomy, active inference and the free energy principle”
- Pezzulo & Sims (2021): “Modelling ourselves: what the free energy principle reveals about our implicit notions of representation”