Understanding scientific practices: The role of robustness notions

This article explores the role of `robustness-notions¿ in an account of the engineering sciences. The engineering sciences aim at technological production of, and intervention with phenomena relevant to the (dis-)functioning of materials and technological devices, by means of scientific understanding thereof. It is proposed that different kinds of robustness-notions enable and guide scientific research: (1) Robustness is as a metaphysical belief that we have about the physical world ¿ i.e., we believe that the world is robust in the sense that the same physical conditions will always produce the same effects. (2) `Same conditions ¿ same effects¿ functions as a regulative principle that enables and guides scientific research because it points to, and justifies methodological notions. (3) Repetition, variance and multiple-determination function as methodological criteria for scientific methods that justify the acceptance of epistemological and ontological results. (4) Reproducibility and stability function as ontological criteria for the acceptance of phenomena described by A¿B. (5) Reliability functions as an epistemological criterion for the acceptance of epistemological results, in particular law¿like knowledge of a conditional form: ¿A¿B, provided Cdevice, and unless other known and/or unknown causally relevant conditions.¿ The crucial question is how different kinds of robustness¿notions are related and how they play their part in the production and acceptance of scientific results. Focus is on production and acceptance of physical phenomena and the rule-like knowledge thereof. Based on an analysis of how philosoophy of science tradtionally justified scientific knowledge, I propose a general schema that specifies how inferences to the claim that a scientific result has a certain epistem ological property (such as truth) are justified by scientific methods that meet specific methodological criteria. It is proposed that `same conditions ¿ same effects¿ as a regulative criterion justifies `repetition, variation and ultiple¿determination¿ as methodological criteria for the production and acceptance of (ontological and epistemological) scientific results