The philosophy of model validation

This chapter will explore the philosophy of model validation, and goes on to describe the Mc l Distortion Method for quantitative model validation. 

Hgur 24.1 Relationships between generic, specific and particular models. 

Suppose we run the particular model to obtain model predictions. Let us now enquire how much logical justification can we have for regarding these predictions as correct  

The basis for an answer to this question was provided by the philosopher Sir Karl Popper in 1934, who was interested in the characteristics of a scientific theory. (We may note here that a dynamic model embodied in a computer program is, of course, a scientific theory - a very well documented theory.) Popper s conclusions were that  

A theory can never be proved by any of its successes, since a new test, perhaps as yet not thought of, may come along that it will fail. Failure in any fair test, on the other hand, indicates a fault in the theory falsifies it. At this stage, effort will need to be spent in improving the theory or devising a completely new theory. 

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