I address the sources that we rely on to increase the epistemic verisimilitude of our scientific theories. I contend that the generation of new and better research methodologies (e.g. mathematical, logical, empirical, etc.) and the provision of more and better empirical data to build and corroborate our theories are the two main sources—in mutual co-determination—to achieve this epistemological aim. I then discuss realist and anti-realist arguments that relate to these two issues. I show not only where the arguments on both sides flounder and why but also what their sensible achievements are. My thesis is that neither the idea that we are approaching truth with the replacement of our theories nor that we should be content with their increasing empirical success does epistemological justice to the results of theory change. Nevertheless, the notion of increasing degrees of epistemic verisimilitude does.