A semantic conception of scientific models for didactics of science

1
A semantic conceptionof scientific modelsfor
didactics of science

• Agustín Adúriz-Bravo
• Universidad de Buenos Aires
• Argentina

2
The modelistic turnin science education

• Scientific models and modelling have been present
  in an implicit way in science curricula.
• In science classes, it has been usual to work
  with the idea that science models the world
  using abstract representations.
• In the last 10 years science education
  researchers, science curriculum developers, and
  science teachers have advocatet for an explicit
  treatment of this construct in the classroom.
• A new requirement emerges there should be
  discussion around the role of models when talking
  about the nature of science.

3
The modelistic turnin didactics of science

• There is a need to make theoretical decisions on
  which views on models of the many available from
  philosophy of science can valuable for research,
  teaching, and teacher education.
• I will argue in favour of a semantic conception
  of scientific models.

4
Semantic views on models

• Any one of a number of recent characterisations
  of the concept of model proposed by a range of
  philosophers that can be situated in the
  semantic conception of scientific theories,
  opposed to the received view in the philosophy
  of science.
• Within such school, several versions can be
  identified from meta-theoretical structuralism
  to the more recent model-based approaches by Fred
  Suppe, Bas van Fraassen and Ron Giere, going
  through several other proposals.

5
Characterisationof the semantic conception

• The focus of meta-theoretical analysis is put in
  how scientific theories give meaning to the world
  and make sense to their users.
• A scientific theory can be fruitfully
  characterised as a family or class of models.
• The theory is constituted not only of a class of
  models, but also of a set of empirical systems
  that such theory intends to account for.
• The theory states that there is substantive
  relationship between its models and its systems
  it empirically asserts that some phenomena are
  adequately accounted for by the models.

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Outline

• Higlighting the merits of a semantic conception
  of models for science education and didactics of
  science
• requires
• a characterisation of how models have been
  conceptualised by different philosophical schools
  in the 20th century
• which in turn requires
• facing the obstacle that the term model is used
  in the natural language, in science and
  technology, and in the philosophy of science with
  a range of different meanings.

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Models in natural language

• P1 Mona Lisa Gherardini del Giocondo posed as a
  model for Leonardo da
• Vinci.
• P2 This toy car is an accurate model of a
  Formula 1 car.

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Models in everyday life
reality
representation
9
Models in everyday life
input
output
10
Models in everyday life
input
output
11
Models in everyday life
model-for
model-from
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Four kinds of models

• A model-input can be a model-for when it is a
  paradigm an archetype or exemplar for something,
  a canon that should be followed, imitated, or
  copied.
• Mother Teresa of Calcutta is a model of
  humanitarianism.

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Four kinds of models

• A model-input can also be a model-from, when it
  is an instance a case, realisation or embodiment
  of something, a representative example of a
  general or abstract situation or of a set of
  principles.
• Amsterdam is a model sustainable city.

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Four kinds of models

• A model-output can be a model-from when it is a
  copy a simplified version, replica, sketch,
  imitation or simulation of something. In this
  case, the model only captures some central and
  characteristic elements of what is being copied
  chosen according to an intentional view.
• Students participated in a model of the United
  Nations.

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Four kinds of models

• A model-output can also be a model-for when it is
  a design a plan, project, scheme, prototype,
  blueprint or scale model of something that does
  not materially exist so far.
• The exhibition features a model of the
  underwater tunnel.

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Model-input-for

• A pendulum is a real object that is studied by
  physics in order to abstract the laws of its
  movement.

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Model-input-from

• A pendulum is a real object that (best)
  exmplifies the physical notion of harmonic
  oscillations.

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Model-output-from

• A pendulum is a highly stylised and simplified
  representation of a swinging object.

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Model-output-for

• A pendulum is a set of specifications to
  understand/construct artifacts with predictable
  behaviour.

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Models in scientific research

• Model denotes a theoretical representation of a
  complex reality that is developed to facilitate
  the study of its behaviour.

abstract, symbolic, theory-laden
praxis mediation
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Philosophical analyseson models

• For logical positivism and the received view (c.
  1920-1960), a scientific model was any example of
  a theory the theory was considered the central
  entity for epistemological analysis.
• The pendulum is one system out of a pool of many
  other systems that obeys some particular laws of
  mechanics.

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Philosophical analyseson models

• For the new philosophy of science (c. 1950-1980),
  the model became a paradigmatic example (i.e.,
  particularly worthy of imitation) of a theory.
• The pendulum embodies the main characteristics of
  simple harmonic motion, and thus serves as
  exemplar to understand other systems.

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Philosophical analyseson models

• Finally, for the semantic conception of
  scientific theories (c. 19702010), the model was
  identified with an intended example of a theory
  (that is, an example that the theory is conceived
  to explain).
• The pendulum is one system out of a pool of very
  few systems for which some specific laws of
  mechanics are proposed.

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• The semantic view adds, to the Kuhnian
  reconstruction of models as cases that have
  been well solved and are thus exemplary, the more
  classical requirement that they can all be
  represented in analogous semi-formal ways, and
  formulated as generally and abstractly as
  possible.
• Thus, semanticism represents a third way
  between the received view and the new philosophy
  of science, purporting to recur to their most
  powerful tools to think about models.
• This double strategy that pretends to
  recover the best of each of the preceding
  periods constitutes one of the fundamental
  characteristics of this semanticist approach.
  (Lorenzano 2001 38)

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• The semantic view synthesises in one construct
  the meanings model-for and model-from.
• Model combinedly capture the two different
  (and, to common sense, somewhat opposed) meanings
  of the Latin word modus. Modus means both
  manner and measure.

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• A manner is to a certain extent identifiable with
  model-for, since it is the way in which something
  exists or occurs.
• A measure is to a certain extent identifiable
  with model-from it is a degree, intensity,
  proportion, or correspondence by comparison.
• Every manner is a measure that an embodied set
  of characteristic properties can serve as a canon
  (unit/pattern) for other embodiments or
  realisations to be compared with.
• A scientific model captures essential elements of
  a system and becomes a way of (analogically)
  understanding other systems.

27

• The semantic view is compatible with both a
  realist reconstruction of science, and with
  empiricist or instrumentalist reconstructions of
  science.
• As Fred Suppe (2000, p. S105) puts it,
• depending on mapping relationships between
  models and phenomena required for theoretical
  adequacy, realist, quasi-realist or antirealist
  verions of the semantic conception of theories
  are obtained.

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• Giere, Suppe and van Fraassen shift their
  interest towards how scientific theories give
  meaning to the world on which they are applied,
  and how they make sense for those who are
  applying them (the cognitive agents, including
  students and teachers).
• They are less interested in the strict logical
  and linguistic structure of theories.
• Opposing the usual syntactic approach, they
  prioritise a semantic, pragmatic and rhetorical
  approach.

29

• G, S and vF assume that theories cannot be
  reduced just to the theoretical propositions that
  constitute them rather, theories also contain
  the facts interpreted by them.
• Scientific theories are not reducible to
  knowledge of propositional nature, since they
  also contain a know-how around the explanations
  and interventions that can be performed with
  them.
• A theory is therefore a family of models, but
  more than the addition of these models, because
  these are linked by logical and experimental
  relationships that give coherence to the whole
  set.

30

• G, S and vF consider that theories are best
  identified and characterised by their
  corresponding classes of models.
• They deem more relevant to meta-theoretically
  study models than theories. This kind of approach
  is called model-based.
• The focus is now placed on understanding the
  nature of scientific models, rather than on
  placing these models within a theoretical network
  of statements.

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• G, S and vF assume that there is no direct
  relationship between what we say (propositions)
  and phenomena.
• This relationship is mediated by models
  understood as abstract representations of the
  world.
• Such representations cannot be reduced to
  propositions or to reality.

32

• These authors consider that the different
  linguistic forms under which the same model can
  be presented are to some extent equivalent.
  They do not assume the primacy of some of these
  forms (the axiomatic, for instance) over the
  others.
• They are much more flexible than standard
  philosophy of science, since non-rigidly
  formalised knowledge can be considered
  theoretical and can be expressed (defined) with
  very different languages scale models, drawings,
  paradigmatic facts, metaphors, gestures
• They can be presented in a very simple way,
  emphasizing only their essential elements so that
  they conserve their explanatory power.