Verification, Validation, and Confirmation of Numerical Models in the Earth Sciences

TLDR

Because natural systems are never closed and model results are always nonunique, verification and validation of numerical models are impossible, and complete confirmation is logically precluded, leaving models to be evaluated only relatively with their predictive value always open to question. The primary value of models is heuristic.

Abstract

Verification and validation of numerical models of natural systems is impossible. This is because natural systems are never closed and because model results are always nonunique. Models can be confirmed by the demonstration of agreement between observation and prediction, but confirmation is inherently partial. Complete confirmation is logically precluded by the fallacy of affirming the consequent and by incomplete access to natural phenomena. Models can only be evaluated in relative terms, and their predictive value is always open to question. The primary value of models is heuristic.