Date of Award


Document Type


Degree Name

Doctor of Philosophy (PhD)

First Reader

Ronald J. Feenstra

Second Reader

Lee P. Hardy

Third Reader

John W. Cooper

Fourth Reader

Thomas M. Osborne, Jr.


This work gives attention to a trajectory that attempts to chart a course from the human quest for happiness and ultimately arrives at a transcendent, universal terminus or summum bonum as the natural end of this quest. This trajectory of ascent has given rise to a specific kind of project in natural theology; namely, the Eudaimonological Argument. Herein I set out to defend the analysis and development of the thought of Thomas Aquinas on this ascent by the 20th century Neoscholastic, Réginald Garrigou-Lagrange (1877–1964). The central thesis contends that Garrigou’s Eudaimonological Argument represents a viable project in natural theology within the Thomist tradition when properly understood in light of its underlying metaphysical principles, specifically formal and final causality. To support this contention, attention is first given to Augustine’s account of happiness and its potential as an argument for God’s existence. However, while he provides criteria which entail God as humanity’s natural end, his account cannot be properly construed along the lines of traditional natural theology. Next, this work turns to Aquinas in order to explore such a project. Although Aquinas provides an extended analysis of happiness and its relation to God, he still left much of the work for a natural theological project along these lines implicit and in need of further development. However, in the work of Garrigou-Lagrange extending Aquinas’ thought, the Eudaimonological Argument comes to full expression. What analysis of Garrigou’s account makes evident is the necessary role of formal and final causality for the argument’s articulation and defense. While Garrigou’s argument is subject to potential defeaters, this work considers and seeks to defend it against these objections. Lastly, the Eudaimonological Argument’s dependence on formal and final causality is further demonstrated by the failure of such arguments which have been attempted apart from these metaphysical foundations. Although Kant and the Transcendental Thomists offered their own version of the argument, it was found that in so doing the argument either moved beyond the critical philosophy or failed to establish its theological conclusions.



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