In recent decades there has been renewed interest in the role of late-medieval nominalism in genealogies of modern thought. William of Ockham, 14th century theologian and philosopher, often plays a pivotal role in such accounts. Ockham has been both credited and blamed for the overthrow of medieval metaphysics and the foundation of empirical science. He has also occasioned all sorts of vituperation for his voluntarist theology and his purported skepticism. Such censure has made it difficult for scholars to appreciate Ockham's philosophical contributions in their own right, especially outside the discipline of Medieval Studies. The dissertation seeks to remedy this state of affairs by examining the philosophical significance of Ockham's work, focusing on his theory of cognition and its implications for philosophical research.

The dissertation argues that Ockham's theory of cognition inaugurates a subjective "turn" that can be traced through Immanuel Kant to modern phenomenology. Rather than "founding" the modern (Kantian) subject, however, Ockham also opens the subject to the possibility that it is always already un -founded in relation to the givenness of phenomena. Thus the dissertation makes two interventions into now common characterizations of modernity as a closed system, predicated on the Cartesian or Kantian subject and ripe for overthrow by post-metaphysical criticism. First, it locates the "modern" subject as far back as William of Ockham. Second, it argues that the modern "subject" is un-founded in its very foundation. That is, the modern subject is two-sided: self-founding yet un-founded in its relation to phenomena. The dissertation defends this reading of Ockham and tests it by exploring similar instabilities in Immanuel Kant's theory of subjectivity.