Model robustness as a confirmatory virtue: The case of climate science

•Many philosophers think that robustness is not confirmatory.•Climate scientists, in contrast, do find certain kinds of robustness confirmatory.•I propose ‘model robustness’ which can be confirmatory, as in the climate case.•Multiple distinct models are random, well-supported ‘experiments’.•Model robustness supports both models' predictions and their causal factors.

I propose a distinct type of robustness, which I suggest can support a confirmatory role in scientific reasoning, contrary to the usual philosophical claims. In model robustness, repeated production of the empirically successful model prediction or retrodiction against a background of independently-supported and varying model constructions, within a group of models containing a shared causal factor, may suggest how confident we can be in the causal factor and predictions/retrodictions, especially once supported by a variety of evidence framework. I present climate models of greenhouse gas global warming of the 20th Century as an example, and emphasize climate scientists' discussions of robust models and causal aspects. The account is intended as applicable to a broad array of sciences that use complex modeling techniques.