Tools or Toys?
|Table of Contents|
|2 The role of models in science|
|2.1 The nature of models|
|2.2 Where models get their credentials from|
|3 Why computer simulations are merely models and not experiments|
|4 The epistemology of simulations at work: How simulations are used to study chemical reactions in the ribosome|
|5 How do models explain in the social sciences?|
|6 Common obstacles for modeling in the social sciences|
If models are mediators between theory and reality in the just described sense, then the next question would be what gives models their credibility or how they can be validated. Obviously, if models are partially independent from theory, we cannot rely on the credibility of the background theory alone. Instead, models draw their credibility from three different sources:
If these are the sources of credibility for models, then the question arises if and how they are be related to each other. The following two conjectures about the mutual relation of these sources seem reasonable:
It seems reasonable to distinguish the models that derive their credibility primarily from the reliance on background theories, background knowledge and modeling techniques from those that are validated by direct empirical testing. The former could be termed “ input-controlled” models and the latter “output-controlled” models. The distinction is of course one of “more or less”. Some models may be both input and output controlled. This distinction is meaningful, because with these two ideal types of models are associated quite different modes of validation. With this terminological convention no general assumption is made about the relatively greater or smaller reliability of the one or the other. But it stands to reason that different levels of credibility or reliability might be associated with input or output-controlled models in specific contexts.
There is not much more that can be said about the credibility of models on this very general level. Further below a case study will be discussed in order to show how these three sources of credibility come into play in a simulation model. But before, a few things need to be said to justify why the terms “model” and “computer simulations” are used more or less interchangeably in this paper.
 In the latter case, however, their success must at least at some point in the past have been assessed by more direct means.