This book addresses central issues in the philosophy and metaphysics of science, namely the nature of scientific theories, their partial truth, and the necessity of scientific laws within a moderate realist and empiricist perspective. Accordingly, good arguments in favour of the existence of unobservable entities postulated by our best theories, such as electrons, must be inductively grounded on perceptual experience and not their explanatory power as most defenders of scientific realism claim. Similarly, belief in the reality of dispositions such as causal powers which ground the natural...