Comment on ‘Of data and models’

The author is to be applauded for probing how data and models are employed in the practice of hydroinformatics. In particular, his approach from the point of view of an engineer who wishes to predict the consequences of unobserved interventions in the aquatic environment is welcome. The purpose of this comment is to scrutinize some aspects of the author's reasoning, which on the whole he justifies on the basis of his admirable experience and intuition, in order to establish whether or not it can be placed on a more sound theoretical footing by recourse to modern theories of uncertainty. I would like to begin by suggesting a change in terminology, a suggestion that, as I hope I ~" demonstrate, is based on more than pedantry. The author refers to 'de~er-"'-fJsychological appeal of causality may be a double-edged ministic' models as the opposite of 'data-driven' mo"d~is. " sword (or crutch), which perhaps is what Bertrand Russell