A semantic conception
of scientific models
for didactics of science
Agustín Adúriz-Bravo
Universidad de Buenos Aires
Argentina
The ‘modelistic turn’
in science education
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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.
The ‘modelistic turn’
in didactics of science
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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.
Semantic views on models
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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.
Characterisation
of the semantic conception
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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.
Outline
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Higlighting the merits of a semantic conception of models
for science education and didactics of science
requires
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a characterisation of how models have been
conceptualised by different philosophical schools in the
20th century
which in turn requires
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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.
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
Models in everyday life
input
output
Models in everyday life
input
output
Models in everyday life
modelfor
model-from
Four ‘kinds’ of models
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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”.
Four ‘kinds’ of models
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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”.
Four ‘kinds’ of models
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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”.
Four ‘kinds’ of models
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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”.
Model-input-for
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A pendulum is a real object that is studied
by physics in order to abstract the laws of
its movement.
Model-input-from
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A pendulum is a real object that (best)
exmplifies the physical notion of harmonic
oscillations.
Model-output-from
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A pendulum is a highly stylised and
simplified representation of a swinging
object.
Model-output-for
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A pendulum is a set of specifications to
understand/construct artifacts with
predictable behaviour.
Models in scientific research
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‘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
Philosophical analyses
on models
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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.
Philosophical analyses
on models
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For the new philosophy of science (c. 19501980), 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.
Philosophical analyses
on models
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Finally, for the semantic conception of
scientific theories (c. 1970–2010), 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.
[T]his ‘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 modelfrom.
‘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 modelfrom: 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.
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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,
[d]epending 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.
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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 ‘knowhow’ 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.
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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.
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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.
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A semantic conception of scientific models for didactics of science