The Concept of Person in St. Thomas Aquinas: A Contribution to Recent Discussion*

THE CONCEPT OF PERSON IN ST. THOMAS AQUINAS: A Contribution to Recent Discussion* ST. THOMAS AQUINAS accepted and consistently defended Boethius' definition of person: "persona est substantia individua rationalis naturae." St. Thomas' analysis of this definition necessarily involves metaphysical questions because of the implications of the terms " substance" and " nature" and moreover it manifests the inescapahle imprint of the theological problematics which surrounded the issue (e.g. the Trinity and the hypostatic union). Both of these influences, metaphysical and theological, have engendered problems of interpretation and criticism. Contemporary discussions of person largely either continue the scholastic controversies or adopt a modern perspective from which to expose apparent contradictions in St. Thomas' doctrine. The purpose of this article will be limited to a consideration of the metaphysical problems concerning the relationship between individual substance, universal, nature, and existence. It is hoped that such a clarification will resolve not only the neoscholastic controversies, but also some of the contemporary problems. I. BOETHIUS' DEFINITION OF PERSON AND ST. THOMAS' EXPLANATION A. BOETHIUS' DEFINITION Boethius develops his definition of person in the Liber contra Eutychen et N estorium after a careful consideration of na- * I have to thank cordially Father Brian Shanley, 0.P. for having revised completely this English version, devoting much time and energy to fit the text and the footnotes to the style of The Thomist. He adapted the version in good style and verified the Latin quotations. 435 436 HORST SEIDL ture and substance.1 In the first chapter he sets out to define nature and discovers four possible meanings. The first and broadest definition, embracing both substances and accidents, describes nature as belonging to all things which by their being can be in some way or another be comprehended by reason: "natura est earum rermn quae, cum sint, quoquo modo intellectu capi possunt." A second definition, comprising substances alone both corporeal and incorporeal, describes nature as anything that can effect or suffer something: " natura est vel quod facere vel quod pati possit." A third sense, taken from the Aristotelian analysis of the motion of natural substances , describes nature as the immanent principle of movement : "natura est motus principium per se et non per accidens." Finally, nature can also refer to the formal cause which provides the specific difference: " natura est unam quamque rem informans specifica differentia" (cf. ST Ia. 29, I ad 4). It is this last sense which is most important. In sum, "nature" is a broad term encompassing both composite beings and their causes. Boethius continues in chapter two by first narrowing the relevant sense of nature to substances (thus excluding accidents ) and then presenting a complete division of substances. The major distinction is between corporeal substances and incorporeal substances. Corporeal subdivides further into inanimate and animate, with animate dividing. into insensitive and sensitive and the latter dividing finally into irrational and rational . Incorporeal subdivides into rational and irrational (the life-principle of animals), with rational incorporeal substances being further distinguished into those that are immutable by nature (the Creator) and those that are not so by nature (the human soul and angels) but may become so by virtue of the immutable substance. Boethius then argues that person cannot be affirmed of inanimate beings or irrational animals. A 1 All citations from Boethius are taken from the Loeb text in Boethius: Theological Tractates and the Consolation of Philosophy, ed. H. F. Stewart and E. K. Rand (Cambridge: Harvard University Press, 1918). THE CONCEPT OF PERSON IN ST. THOMAS AQUINAS 437 final distinction of :substance into universal and particular leads to the conclusion that person must refer to an individual. Thus the background is set for the definition of person which opens the third chapter: " naturae rationalis individua substantia ." Person must be an individual substance of a certain nature, namely rational, which nature accounts for the form or specific difference of the particular substance (the fourth meaning of chapter 1) . The connection of this definition with Aristotle 's definition of man as a rational animal is unmistakable. It should also be noted that this definition of person is applicable not only to man, in whom the rational nature is not identical with his substance, but also to the...