Models

Scale Models

As their name suggests, scale models involve a change of scale. They are always models of something, and they typically reduce selected properties of the objects they represent. Thus, a model airplane stands as a miniaturized representation of a real airplane. However, scale models can stand as a magnified representation of an object, such as a small insect. Although scale models are constructed to provide a good resemblance to the object or property being modeled, they represent only selected relevant features of the object. Thus, a model airplane will almost always represent the fuselage and wings of the real airplane being modeled, but it will seldom represent the interior of the aircraft. Scale models are a class of iconic models because they literally depict the features of interest in the original. However, not all iconic models are scale models, as for example James Watson and Francis Crick's physical model of the helical structure of the DNA molecule. Scale models are usually built in order to present the properties of interest in the original object in an accessible and manipulable form. A scale model of an aircraft prototype, for example, may be built to test its basic aerodynamic features in a wind tunnel.

Analogue Models

Analogue, or analogical, models express relevant relations of analogy between the model and the reality being represented. Analogue models are important in the development of scientific theories. The requirement for analogical modeling often stems from the need to learn about the nature of hidden entities postulated by a theory. Analogue models also serve to assess the plausibility of our new understanding of those entities.

Analogical models employ the pragmatic strategy of conceiving of unknown causal mechanisms in terms of what is already familiar and well understood. Well-known examples of models that have resulted from this strategy are the molecular model of gases, based on an analogy with billiard balls in a container; the model of natural selection, based on an analogy with artificial selection; and, the computational model of the mind, based on an analogy with the computer.

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