Empirical Adequacy vs Effect Completeness Jeffrey Ketland * Institute of Philosophy University of Warsaw April 2, 2020 Abstract The standard analysis of empirical adequacy—advocated by instrumentalists and constructive empiricists—is that a scientific theories is empirically adequate just if “what it says about observable things and events in the world is true”. It is noted that, on this analysis, the empirical adequacy of a scientific theory amounts to a claim of consistency with observation. However, it is noted that, within science, what is typically required of scientific theories is that they imply or entail known observational effects, rather than merely be consistent with such effects. A separate notion of effect completeness is provided. Contents 1 Introduction 1 2 Effects 3 3 Worrall’s Objection 4 4 Effect Derivations 4 5 Effect Completeness 6 1 Introduction According to van Fraassen’s constructive empiricist view of science, Science aims to give us theories which are empirically adequate; and acceptance of a theory involves a belief only that it is empirically adequate.([15]: 12) * Email address: jeffreyketland@gmail.com 1