Fictions, maps, and structures in forecast models. February 2017.
abstract   bibtex   
The main aim of this paper is to discuss some epistemic aspects of forecast models, especially in the context of “model fictionalism,” promoted and discussed by P. Godffrey-Smith, M. Suarez, and especially R. Frigg. Forecast models are designed to predict the future states of a system from what we know about its past and present states, and from our knowledge of laws of nature, causation, mechanisms, symmetries, etc. This paper argues that the very process of building forecast models implies ultimately the insertion into the model of several types of fictional entities. We discuss here especially fictional structures, as opposed to fictional objects, and on their role in this type of models. The main epistemological question is whether we can produce knowledge about the future by employing these fictional structures. The paper has also a metaphysical component, as it engages the ontological status of future objects, the distribution of properties over populations of models, and the ontology of fictions and their representational role. The epistemology of forecast models, as a second component envisaged here, is also peculiar, in respect of epistemic access we have to the target space. Models in general represent a target system, which is real. Future objects have a different status: they are real, but not known and not accessible by direct observation (unlike the target system of most our scientific models) Are forecast models completely target-less? What means to have a representational target (partially or totally) in the future? In relation to the variability (or lack thereof) of laws of nature, the paper argues that fictions in forecast models are non-mimetic, but nevertheless nomic possibilities. The paper emphasizes the difference between representing future states of a system and representing its past states. Mapping the future states of a system depends on assumptions which the modeler needs to make explicit. The paper does not discount therefore the difference in epistemic access between past, present, and future when it comes to models. The conclusion of this paper is that forecast fictional structures, with properties distributed over populations of models, enable the modeler to represent a target system in the future. Fictional structures serve a better role in forecast models than hypotheses, which are typically expressed in first order language.
@unpublished{noauthor_fictions_2017,
	address = {submitted to the monist, synthese},
	type = {word file available on demand only},
	title = {Fictions, maps, and structures in forecast models},
	abstract = {The main aim of this paper is to discuss some epistemic aspects of forecast models, especially in the context of “model fictionalism,” promoted and discussed by P. Godffrey-Smith, M. Suarez, and especially R. Frigg. Forecast models are designed to predict the future states of a system from what we know about its past and present states, and from our knowledge of laws of nature, causation, mechanisms, symmetries, etc. This paper argues that the very process of building forecast models implies ultimately the insertion into the model of several types of fictional entities. We discuss here especially fictional structures, as opposed to fictional objects, and on their role in this type of models. The main epistemological question is whether we can produce knowledge about the future by employing these fictional structures. The paper has also a metaphysical component, as it engages the ontological status of future objects, the distribution of properties over populations of models, and the ontology of fictions and their representational role. 
The epistemology of forecast models, as a second component envisaged here, is also peculiar, in respect of epistemic access we have to the target space. Models in general represent a target system, which is real. Future objects have a different status: they are real, but not known and not accessible by direct observation (unlike the target system of most our scientific models) Are forecast models completely target-less? What means to have a representational target (partially or totally) in the future? In relation to the variability (or lack thereof) of laws of nature, the paper argues that fictions in forecast models are non-mimetic, but nevertheless nomic possibilities. The paper emphasizes the difference between representing future states of a system and representing its past states. Mapping the future states of a system depends on assumptions which the modeler needs to make explicit. The paper does not discount therefore the difference in epistemic access between past, present, and future when it comes to models. 
The conclusion of this paper is that forecast fictional structures, with properties distributed over populations of models, enable the modeler to represent a target system in the future. Fictional structures serve a better role in forecast models than hypotheses, which are typically expressed in first order language.},
	month = feb,
	year = {2017},
	keywords = {DEKI (Frigg\&Ngyuen), Fictions, Models and Idealization},
}

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