This book presents an empiricist alternative (‘constructive empiricism’) to both logical positivism and scientific realism. Against the former, it insists on a literal understanding of the language of science and on an irreducibly pragmatic dimension of theory acceptance. Against scientific realism, it insists that the central aim of science is empirical adequacy (‘saving the phenomena’) and that even unqualified acceptance of a theory involves no more belief than that this goal is met. Beginning with a critique of the metaphysical arguments that typically accompany scientific realism, a new characterization of empirical adequacy is presented, together with an interpretation of probability in both modern and contemporary physics and a pragmatic theory of explanation.