Project Dissertations


Dissertations by Student Members

Dissertations in Progress by Student Members

(in alphabetical order)

Nathan M. Blackerby, Marquette University, Milwaukee, Wisconsin, USA.

(Tentative) Thomas Aquinas on Esse Absolutum and the Soul-Body Relation.

    Email: Nathan Blackerby <>

    Director: Prof. Richard C. Taylor, Marquette University, Milwaukee (Tentative)


Traci Phillipson, Marquette University, Milwaukee. Aquinas, Averroes, and the Moral Self.

   Email: Traci Phillipson <>

   Directors: Prof. Richard C. Taylor, Marquette University, Milwaukee, & Prof. Andrea Robiglio, Leuven. IN PROGRESS

Completed Dissertations

Daniel D. De Haan, University of St. Thomas, Houston, Texas, USA. (Tentative) The Doctrine of Being in Avicenna’s Metaphysics of the Shifâ’: The Introduction of Modalities in to First Philosophy.


    Director: Prof. R. E. Houser, University of St. Thomas, Houston (Tentative)

    Abstract (Tentative)

    The central problem of Occidental metaphysics is the problem of being. In the Metaphysics of the Shifā’ Avicenna sets forth his interpretation of metaphysics as an Aristotelian science whose  subject is being as being. The First Cause is not the subject of first philosophy, but is the ultimate principle and cause of being qua being and that which follows upon being.  But what is being for Avicenna? This thesis approaches Avicenna’s doctrine of being within the historical context of his Greco-Arabic antecedents.  Avicenna achieves his own answer to the problem of being through his completion of al-Fārābī’s introduction of modalities into Aristotelian metaphysics and logic. This thesis proposes that Avicenna’s doctrine of being can be characterized by the most fundamental determination of being.  For Avicenna, this is necessary existence.  A being is a being by virtue of its necessary existence, whether it exists necessarily through another, like all of creation, or it is necessary existence in itself, like the First Cause.  It will be shown that the central place of existence and modalities provide Avicenna with a novel Aristotelian response to the metaphysical and theological doctrines of the mutakallimiin and other philosophical contemporaries.  Finally, contrary to the interpretation that Avicenna is an essentialist, the conclusion of this thesis will show that Avicenna’s doctrine of being is more properly characterized as an “existential modalism.”

Dr. David González Ginocchio, Posibilidad y lógica de la esencia: estudio sobre Avicena y Escoto [The Logic and Possibility of Essence: A Study on Avicenna and Duns Scotus]

    Director: Dr. Luis Xavier López-Farjeat (Universidad Panamericana)

    Degree conferred January 2010, Aula Magna, Universidad Panamericana

    Email: David González Ginocchio <>


This dissertation seeks to explain the notion of “essentialist metaphysics” as applied to Avicenna and Duns Scotus. It is divided in three parts.

In the first one I argue that the primordial distinction in Avicenna’s metaphysics is that between being according to apprehension (al-wujûd al-khâss) and being according to assertion (al-wujûd al-îthbâtî). I believe this interpretation explains the reason why Avicenna sustains that there are three primary notions in the intellect and yet only being is the subject matter of metaphysics: the determined sense is built around thingness (shay’iyya) and the assertive sense is built around necessity (darûrî). Their correlation can be used to explain the categories (substance as necessary determination, accidents as necessary-by-other determinations), causality (the thing that is determined by other and the thing that is undeterminable but by itself), and ultimately God (the actual necessary-thing-existent, unreachable for the human intellect). A parallel is drawn between this conception and that of Scotus’ essential order, also centered on essences being caused. The second part studies both authors’ doctrine of causality, especially in the different dependence formal causality has on matter and in the extrinsic causes. I argue that God cannot be fully integrated in this causal scheme, inasmuch as causes are co-related, and God is not dependent on anything ad extra. The parallel is here drawn on the basis of the middle term, which Avicenna employs and Scotus’ logic systematizes. The scientific order is thus correspondent with the essential order of causal existence. The third part studies the notion of intellect, and discusses the possible knowledge of real, individual essences. I argue that the infamous “third state” of the essence in Avicenna (essentia tantum) corresponds not to the logical-universal activity of the human intellect or the actual existence of individual beings, but to the emanative action of the Giver of Forms. I try to show how this entails that, for Avicenna, the universal is the authentic form of knowledge, and how this is coherent with his psychology. In Scotus, however, the emanative scheme is abandoned for the sake of the creature’s dependence on God’s free willing: it is the individual existent the one that corresponds to the most perfect state of existence, and this state is unattainable to the intellect alone, rather, it requires the special features of the will, both in esse (God’s will) and in cognoscendi (intuition). I show in the conclusions how Scotus’ position is in many ways an answer and a further development of Avicenna’s metaphysics, and how his own philosophy is passed on in three fundamental ways or “reductions”: from the analogy of being to its univocity, from potency to possibility, and from rational character of the intellect to a naturalized one, its place of free, rational faculty supplanted by the will. 

Dr. Max Herrera, Arabic Influences in Aquinas’s Doctrine of Intelligible Species.

      Director: Prof. Richard C. Taylor, Marquette University

      Committee members: Prof. David Twetten, Marquette; Prof. Noel Adams, Marquette;

                                          Prof. John O’Callaghan, University of Notre Dame

      Philosophy Department, Marquette University, Milwaukee, WI

      Degree conferred May 2010. Available for Download 21 May 2011 at


       Email: Max Herrera <>


In contemporary literature, one can find much information concerning Thomas Aquinas's doctrine of intelligible species. However, none of the literature takes into account how and why Aquinas developed his doctrine of intelligible species. Often, it is purported that Aquinas is just following Aristotle. However, this is not the case. There are aporiae in the Aristotelian corpus, and those who followed Aristotle tried to resolve the intellection and hylomorphism aporia, an aporia that arose as a result of denying Platonic forms and affirming hylomorphism. Among those who attempted to resolve this aporia were Avicenna and Averroes from whom Aquinas drew and developed his doctrine of intelligible species. Avicenna's and Averroes' influence on Aquinas's doctrine of intelligible species is the focus of this dissertation. In addition, Aquinas's hylomorphic doctrines and natural and supernatural psychologies are explicated, and the influence of Avicenna and Averroes on Aquinas's psychologies is highlighted. Finally, the arguments posed by contemporary scholars as to whether Aquinas is a direct realist or a representationalist are reviewed in light of the Arabic contributions and Aquinas's synthesis.

Dr. Katja Krause, King's College London, UK.  

Dissertation title: Aquinas' Philosophy of the Beatific Vision: A Textual Analysis of his Commentary on the Sentences

in Light of its Greek, Arabic, and Latin Sources

Thesis Supervisor: Prof. Peter Adamson

Examiners: Prof. Deborah Black, University of Toronto, Prof. Cecilia Trifogli, Oxford University

Degree Conferred: TBA

email: or


"The beatific vision is commonly regarded as a thoroughly theological, not to say mysterious, topic by philosophers and historians of science alike. Yet in his Commentary on the Sentences, the young Thomas Aquinas develops a systematically sophisticated theory of the beatific vision per essentiam that seeks to reconcile the truths of philosophy with the Truth of theology. This thesis investigates Aquinas’ extensive use of Greek, Arabic, and Latin sources, against a historical context in which theologians sought to rise to the rationalist challenge of the emerging Aristotelianism. I provide a close textual analysis of Aquinas’ earliest treatment of the beatific vision, and identify the fundamental philosophical principles upon which it rests. Most prominent among these is the Aristotelian principle of noetic identity. I argue that, in ways unprecedented for a medieval theologian, Aquinas promotes the beatific vision as the cornerstone of human teleology by intertwining philosophical accounts of human happiness and of the limits of human noetics with traditional Christian eschatology. He also makes this vision the foundation of his science of theology, thus providing an independent philosophical reason for accepting that such a vision will be granted in the afterlife. The thesis concludes with an evaluation of the philosophical viability of Aquinas’ earliest account of the beatific vision, and touches upon the further development of his doctrine in selected mature works."

Dr. Rosa E. Vargas, Marquette University, Milwaukee, Wisconsin, USA.  Thomas Aquinas and the Apprehension of Being: Conclusions from Thirteenth-Century Semantics.

    Email: Rosa Vargas della Casa <>

    Director: Prof. David B. Twetten, Marquette University, Milwaukee.


    Aquinas’ famous comments in his early Scriptum on the Sentences (c. 1251-52) regarding the intellect’s apprehension of essence and esse have traditionally been interpreted as grounding Aquinas’ doctrine on the judgment of esse. For Aquinas, it appears, what the intellect apprehends in a simple concept is essence. Since esse, for him, is not an essence, it cannot be the object of conceptualization. Therefore, most Aquinas scholars conclude, no concept of esse is possible; esse is grasped by the intellect only in judgment. The claim that no genuine concept of esse is possible, however, is inconsistent with Aquinas’ theory of signification. A term’s signification is constituted, at least in part, in its “signing relation” with some “concept” in the mind. If, as on the traditional reading, there is no concept of esse, the term ‘esse’ is left without signification. To respond that the term ‘esse’ “signs” not a concept but the judgment in which esse is apprehended is in direct conflict with Aquinas’ claim elsewhere that no term, including ‘ens’ and ‘esse’, signifies a judgment. I propose an alternative interpretation to Sent., one that leaves open the possibility of a conceptual apprehension of esse.  The alternative reading explains Aquinas’ remarks in light of his theory of signification, in particular the signification of esse by both propositions and the terms ‘ens’ and ‘esse’. Despite the Sentences’ affirmation of a real distinction between a thing’s esse and essence, together with different ways the human intellect apprehends each, it does not follow that the human intellect cannot conceive esse in the way it conceives essences, that is, in a simple conception.