Chemistry Reference
In-Depth Information
These are problem relative - there is a model for the blood system of a mammal and
another for the nervous system, both abstracted from the body of the animal in
question. To create an analytical model the anatomist must be able to observe
the body of the animal in question as a concrete source of the abstract lay out of the
various anatomical systems that can be represented in diagrams. Newton
s model of
the solar system as a system of perfect material spheres obeying Kepler
'
s laws of
motion and the inverse square law of gravitational attraction was derived by
abstraction and idealization of observable fears of the actual solar system (Frigg
2010
: 251-268). Analytical models can be wholly pictorial as in anatomy or they
can be abstract and partially mathematical as in the Newtonian cosmology.
2. Some models are representations of subjects that are different from the
sources of the content of the model - paramorphic models. Usually these models
are created to fill gaps in our knowledge, particularly of the fine structure of
substances under study. Watson and Crick made a model of something they had
not observed, namely the previously unknown structure of the germ plasm.
By attending to how the model behaved or could behave they found a sufficient
number of analogues to the behavior of real DNA that the model quickly became
authenticated as the structure of DNA. But best of all eventually experimental
studies of the DNA molecule revealed a structure that was sufficiently similar to
their model. Some paramorphic models such as the kinetic theory of gases quickly
attract a mathematical as well as a pictorial interpretation.
The possibility of creating mathematical representations of analytical and
paramorphic models leads to a second general distinction in model kinds.
Formal models
are mathematical systems representing processes in such a way
that representing the phenomena to be explained in mathematical terms, assigning
values to variables, and then performing the requisite formal operations as
representing whatever process is under study, yields new and consequential values
for the relevant variables. Formal modeling is valuable for many scientific projects
but unless supplemented by a material interpretation is empty as a source of
explanations.
Iconic models
are concrete representations of things and processes as they are or
as they might be imagined to be in nature. Experimental programs can often be
devised to explore the relevant natural domain to try to find such beings or good
analogues of them. An iconic
model
exists in the same category as its subject -
e.g. as a material thing, as a process, as an abstract structure. A model is related to
its subject by similarities and differences - in general a model is an analogue of its
subject (and a subject is an analogue of any of its models). Model based cognition
depends on semantics (content) of a discourse rather than its syntax (logical form).
Iconic models play an important role in providing explanations of phenomena. For
example, they can be used as representations of the so far unobserved generative
mechanisms that underlie observed processes, and are used to support hypotheses
as to the causes of phenomena. For the most part they represent the internal features
of the entities in which causal patterns are observed and affordances obtained.
For example Bohr
'
s planetary electron shell model of the internal constitution of
atoms explained the spectra obtained from many chemical elements.
'
