23 June 2006

Three types of models...

I distinguish three kinds of models used in research.

The first kind generates unexpected predictions that can be tested and thus reveal new insights. These models are necessarily quite simple, because simplicity and elegance is a precondition for acceptance of a model that makes novel predictions. Why? Because simple models can be understood readily. This makes it possible for people to evaluate how the model's unexpected predictions come about.

The second kind are modifications of simple, established models that explain things the established models couldn't explain. An established model may fall from favour because it does not predict important new observations. Models that are modifications of existing models can save the original model, which may otherwise have been abandoned for a completely new, and perhaps immature model. The usefulness of this second kind of model lies in conserving and preserving valuable accepted wisdom.

Finally, there is a third kind of model. For my taste, all models belonging to this category should undergo refinement until they fall in either of the first two categories.....

So. Don't you agree there are only two kinds of useful models?