By offering a historical overview of the problem of universals and by focusing in the contributions of the medieval philosopher John Duns Scotus and the founder of American Pragmatism, Charles Peirce, the article introduces Peirce's insight on the problem. Such insight is tracked by explaining the connections between Aristotle, Duns Scotus, and Peirce. Peirce's account was named by himself 'Scholastic Realism', and such Realism of universals aims to provide a feasible account for contemporary Scientific Realism. The problem of universals, after such a reading, appears as a continuous and vibrant issue that defines both traditional and contemporary philosophical problems.