Karl Popper's philosophy of science includes both falsificationism and realism. I explore the relationship between these two positions in his philosophy and find a strong tension between them. Drawing upon this tension in Popper's philosophy, I explore the general relationship between falsificationism and realism in an effort to determine whether or not the two positions can be successfully combined. Rather than criticizing falsificationism, I focus instead on the realist side of the tension and seek to resolve the tension through the introduction of an alternative form of scientific realism. I examine three alternatives in detail: Hilary Putnam's internal realism, Richard Boyd's realism, and Ian Hacking's entity realism. Internal realism is shown to be an unsatisfactory solution because of its failure to incorporate a notion of approximate truth. Boyd's version of realism is also shown to be unsatisfactory due to its ascription of absolute approximate truth to scientific theories. Hacking's entity realism, while consistent with falsificationism in many respects, is also shown to be problematic due to its apparent reliance upon induction. Finally, I propose a solution to the problem, which consists in the elaboration of an alternative version of scientific realism based primarily on a reinterpretation of Hacking's entity realism that stresses non-inferential knowledge of causes. I also argue that the reinterpreted form of Hacking's realism can be used to support Boyd's notion of a theoretical tradition, although one of entities and their causal properties rather than one of approximately true theories.