Both present-day historians of philosophy and those working in the past two centuries have considered the thought of Duns Scotus regarding the philosophical problems of universals and individuation as laying the groundwork for much of the philosophical speculation of the fourteenth and fifteenth centuries. Their judgment is well founded, being based on numerous texts in writers such as William of Ockham, Adam Wodeham, Walter Burley, and a host of others whose starting points in discussing both universals and individuation were often the views of Duns Scotus. Furthermore, as the problem of justifying and delimiting the range of natural knowledge became more and more central to philosophical as well as theological investigation, the influence of Duns Scotus on the two problems under discussion continued to grow. Realists as late as the sixteenth and seventeenth centuries looked to Scotus’s works for supporting arguments and conceptual tools whereby to salvage their claims that universals exist outside the mind, whereas the conceptualists and nominalists of later centuries often began their critique of contemporary opponents by pointing out the weaknesses in Scotus’s theories. The historical importance of Scotus’s thought on the subjects being considered here is then clear enough. But the systematic value of his solutions to the problems of universals and individuation should not be overlooked. Several contemporary philosophers working in the areas of metaphysics and epistemology appeal to distinctions bearing striking resemblances to those advanced by Scotus and his followers, especially regarding the problem of individuation.