Thomas Aquinas on Person and Thomistic Personalism

By: Rudi te Velde (School of Catholic Theology, Tilburg University)

In the Catholic tradition of theological-moral reflection on the human person, the term “Thomistic personalism” is a commonly accepted label for a type of personalism that takes as its point of departure the ideas of Thomas Aquinas (1225-1274) on the person. [1] It is generally recognised that Thomas himself was unfamiliar with the specific philosophy of personalism that arose in response to certain nineteenth-century philosophical developments, such as the threat posed by scientific materialism to the unique subjectivity and singularity of the human person. Nevertheless, many personalist thinkers from the Catholic tradition have turned to Aquinas for ideas that could be used as building blocks for constructing a relevant personalist philosophy from Christian inspiration. In 1961, for example, Karol Wojtyla presented a paper entitled “Thomistic Personalism”, in which he argued that twentieth-century personalism could build on Aquinas’s thought about the human person, even if there was no fully developed personalism to be found in his writings. What Wojtyla had in mind, then, was not a strict “personalism according to Aquinas”, but a more moderate “Thomistic personalism”, drawing on the inspiration offered by Thomas’ thought (and by the later Thomistic tradition) on the notion of person. Thomistic personalism, in this version, goes beyond the ontological analysis of person as mode of existing and complements it with the insights of twentieth-century personalism, especially with regard to the subjective dimension of personal selfhood and its transcending orientation to objective values. It is presumed, therefore, that Thomas has to offer valuable insights into what it means to be a person, which are of great importance for contemporary philosophical reflection on the person. With this in mind, I will first present a general account of Thomas’ understanding of the person as it applies to human beings; and secondly, I will discuss some instances of what might be called “implicit personalism” in Thomas, especially his view of the integrity of human moral agency and his defence of the spiritual individuality of the human subject. Some discussions in Aquinas may contribute to a better understanding of the unity of the human person, even if the term person is not used explicitly.                

Thomas on the Definition of Person

In the writings of Thomas, it is particularly in the theological context of his treatment of the Christian dogmas of the Trinity and the Incarnation that attention is paid to the meaning of person and not, as might be expected, in the context of his treatise on the human being (de homine) in the first part of the Summa Theologiae. The word persona gained prominence in the third and fourth centuries as a way of resolving debates about the central dogmas of Christianity. The doctrine of the Trinity, as defined by the Council of Nicaea-Constantinopel, is the belief that God is the one and only instance of the divine nature, but consists of three distinct persons. The doctrine of the Incarnation is the teaching that Jesus Christ is one person, who is subject of human nature as well of divine nature.

The conceptual clarification of these Christian doctrines requires an philosophical analysis of the notion of person, which is special in that it is not a categorical term used to identify and classify natures, but is used in common language to denote the individual possessor of a nature or property. A person is not so much a ‘what’, part of the definition of a thing or an element of a universal structure, but rather a ‘who’, a particular someone exercising its own individual existence   

The introductory question on divine persons in the Summa Theologiae (ST I, 29) begins with a conceptual clarification of the notion of person on the basis of the classic definition of person, framed by Boethius (480-525): “an individual substance of a rational nature” (naturae rationabilis individua substantia).  For Thomas, this is the most appropriate definition of a person. There were other definitions in his time, such as that of Richard of St Victor, who defined a person in terms of the incommunicability of its being, what we would call the unicity of a person. For Thomas, however, the feature of incommunicabilitas is already included in the meaning of the term individual (see ST I, 29, 3 ad 4). Boethius’ formula is construed with help of some keywords taken from Greek philosophy and subsequently translated into Latin, such as “substance” (ousia), “nature” (phusis), “subsistence” (hypostasis). These and other terms form part of the conceptual apparatus with help of which Thomas construes the Christian doctrine of the one God in three persons. 

On the basis of Boethius’ definition, Thomas develops a thoughtful interpretation of the ontology behind this formula. In contrast to modern philosophy, which primarily conceives of the person in terms of human subjectivity and self-consciousness, we see that Thomas accounts for the idea of person in terms of the specific mode of existing of human individuals. It is assumed that the term person is used in relation to individuals; it is not human nature in general that is called person, but singular instances of that nature, such as Socrates or Thomas, concrete individuals with a proper name, sign of their incommunicable mode of existence. A person exists in the singular, this or that human being.

In this respect, Thomas’ understanding of the word person is not much different from the way we use the word person in everyday language; for example, we say that the elevator has but room for five persons or that my sportscar has only room for two persons. However, Thomas is not primarily interested in this numerical use of the word person as such; the central question he is asking in his clarification of Boethius’ definition is why we use a special name for human individuals. In other words, what is special about human individuals? Why do they deserve a special designation. We do not normally speak of persons in the case of dogs or cats (although they may be given a proper name, animals do not identify themselves by means of a name as sign of their unique identity). Thomas argues for the special use of person for human individuals in two steps. First, he points out that, in the order of categories, individuality applies in a more special way to substance, the first category, than to accidents. This is because a substance is individualised in and through itself, whereas an accident is individualised through its subject; the quality “white” becomes “this particular instance of white” because of the subject in which the form is received. This is the reason, says Thomas, why we use special names for individual substances, such as “hypostasis” or “first substance”. In short, a person is an individual substance, that is, a subsisting reality that possesses its own being in a complete way, in itself and through itself.

The second step consists in the observation that substances endowed with reason or intelligence have an even more special and higher mode of being an individual, since they have mastery over their acts (dominium sui actus) and act on their own (per se agunt). Hence singular instances of rational substances deserve a special name: person. It appears that, for Thomas, the term person is used specifically to denote human individuals, in view of the fact that they are free and rational agents who have mastery over their actions. Persons are such that they are capable of acting on their own, with knowledge and free will.

Evaluation

The focus of Thomas’ interpretation of Boethius’ definition is on the ontological constitution of what we call a (human) person. It lacks characteristic features which are generally considered essential to Christian (or Catholic) personalism, such as the unique dignity of the human person, the aspect of subjectivity, and the self-awareness of the person as the centre of his or her actions. Thomas offers an important ontological clarification of the notion of person, but for a full account of personalism as a rich anthropological and moral vision of the human individual one must rely on other sources. What is missing in Thomas’ concept of person is, first of all, the idea of relationality. Contemporary personalists, such as Martin Buber and Emmanuel Levinas, often emphasises the interrelational character of the person. Essential for being a person is the relationship to the other. In this sense, persons exist only in the plural. I am person in relation to other persons. Now, the idea of relationality is part of Thomas’ view of the persons in God. Each of the divine persons signifies a relationship, a being-to-the-other. But the relational character of the divine persons does not have consequences for how Thomas conceives of the human mode of personhood. The trinitarian notion of “subsistent relationship” is an ontological unicum. Another aspect missing in Thomas is the personalist understanding of the human individual as a unique and irreplaceable person, the bearer of that special quality we call “dignity”. For Thomas, the individuality of rational substances is seen as special because of the way in which they act (per se agere). This aspect receives full attention in the context of his account of moral agency, but it is not explicitly elaborated by him in terms of the dignity of a person.

The dignity of the human person

Can we find in Thomas the idea of the special dignity of the human person? It is interesting to note that the expression dignitas personae appears several times in the writings of Thomas, but in a sense that seems to be quite different from the modern claim that persons have a unique and unconditional worth called “dignity”, irrespective of their social rank and position. The modern idea of human dignity is usually associated with the moral philosophy of Immanuel Kant. For Kant, human dignity is a status that places human life above any price. Goods have a price, that is, a relative value, while the human person, as an end in itself, has an intrinsic value, dignity. The human person has a special dignity in so far as he, as a rational being, is the bearer of the moral law. Contemporary forms of personalism generally follow this Kantian approach to human dignity. Dignity, and the moral status implied by it, is then something common to all human beings.

Instead of this moral notion of dignity, which forbids a pure instrumental use of the person, being an end in itself (Selbstzweck), we see Thomas argue that person signifies a special ontological perfection. Explaining why the term person may apply to God, he states that “person signifies what is most perfect in all nature - that is, a subsisting individual of a rational nature”.[2] The particular perfection (or dignity) of being a person is grounded in the combination of rationality and subsistence (per se existens).

In the same text (29, 3), the notion of dignity in relation to person is mentioned and briefly discussed in one of the objections. Here Thomas refers to the etymology of the word person. The Latin persona has its origin in Greek drama, where the prosopon, or mask, was identified with the role the actor would play in a play. The mask referred to the character represented by the actor. In so far as these characters represented famous men, the word person was also used, Thomas explains, to denote those who held high dignity. He gives the example of those who held high office in the Church, a bishop or a cardinal. In this sense one can speak of the person of a cardinal, which means not the empirical individual but the bearer of the dignity of an office. The in this context remarkable expression dignitas personae is used by Thomas in this sense to indicate the special dignity of those who hold high positions in society or in the Church.[3] As such, it is the opposite of “dignity” as denoting the unconditional moral worth of a human person, regardless of social rank or status. From dignity in this social sense, Thomas moves on to dignity in an ontological sense. It is a great dignity, he says, to exist in a rational nature; and that is why every individual with a rational nature is called a “person”.    

The implicit personalism in Thomas Aquinas

As we have said, personalism is not an explicit theme in Aquinas, nor is the term person used as a label for a philosophical defence of the special moral status of the human person. Implicitly, however, certain personalist accents and motives are present in his understanding of the human person. I would like to briefly discuss three characteristic themes in which such a personalist accent can be discerned. The first is the prologue to the second part of the Summa Theologiae, where the special moral agency of the human person is introduced in a programmatic sense. The second place in Thomas’ work that is interesting from the point of view of the personal status of the human being is a text in which he comes to speak of the twofold sense of human individuality, firstly as it is explained in terms of the multiplication of the soul by bodily matter, and secondly in terms of the individuality of the spiritual (rational) soul itself. The third place where a certain personalist motive can be detected is in the critique of Averroes’ thesis of the unity of the intellect. Here we see Thomas defend the integrity of the human individual as the knowing and acting person.

The human agency (prologue I-II)

The purpose of the prologue which opens the second part of the Summa Theologiae is, first of all, to announce to the reader the principal subject of that part. The subject of the second part can be indicated as the work of the “rational creature”, that is man (homo) in respect of his free and rational agency. At the same time the prologue must connect the second part with the first partt. The connection consists in the special relationship that exists between God - the principal subject of the first part - and the human creature. The book of Genesis says that man was created “in the image of God”, a key notion in the Christian anthropology. The notion of imago Dei is specified in terms of the proper modus operandi of both agents; in his free and rational way of acting, man imitates God’s person-like way of acting in his creation:

Since, as Damascene states (De Fide Orthod. ii. 12), man is said to be made to God’s image, whereby ‘image’ implies an intelligent being endowed with free-will and self-movement: now that we have treated of the exemplar, i.e., God, and of those things which came forth from the power of God in accordance with His will; it remains for us to treat of His image, i.e., man, inasmuch as he too is the principle of his actions, as having free-will and control of his actions.   

The prologue draws an analogy in terms of exemplar and imago between God’s work of creation and man’s work of rational freedom. Creatures come to existence by the power of God in accordance with his will and intellect. The way in which God acts in his creation, with power, will and intellect, is presented as the exemplary model of the way in which the human person is able to act, being the leading principle of his proper activities. The human creature acts in a person-like way, with reason and will, like God in his work of creation. To speak in this context of a certain implicit personalism is justified by the emphasis Thomas places in his interpretation of the definition of person on the special mode of acting of persons. As we have seen, the word person signifies individual substances endowed with reason (and will), which have “mastery over their acts, and thus are not merely acted upon like other substances, but act of themselves, by their own initiative (per se agunt).”

We see that in the prologue quoted above the connection between the first and second part of the Summa is established by means of the relationship between exemplar and imago, God’s work of creation and man’s work of rational freedom. This connection can be elaborated on further by pointing at the programmatic presence of the vocabulary of gubernatio (government, God as governor of the universe) and the related concept of motio ad bonum[4] (leading the creature to the good, or as applied to the human creature, leading oneself freely to the good on the basis of knowledge). The first part of the Summa concludes with a treatment of divine government as part of God’s work of creation. It is through his government that God moves all creatures to their end and good (motio ad bonum). Government implies care: God takes care of his creatures in view of what is good for them. Well, in the second part, the treatment of divine government is continued from a new and different perspective. The focus is now on the particular way in which the rational creature moves itself to its end according to a moral rule. The “rational creature” is not, as any other creature, merely passively subject to God’s government, leading all creatures to their end like an arrow shot by the archer, it even actively shares in that government in so far as it moves itself in its actions, with reason and free will, to the end of its life. In short, the human creature is a personal agent.

The moral agency of the human person can be characterised in terms of rational self-government. This is in line with another important text from the second part about the moral rule by which the human person is able to act through itself in the light of natural reason by which he discern what is good and what is bad, grasping the good as what must be pursued and bad as what must be avoided.    

Now among all creatures, the rational creature [man] is subject to divine providence in a more excellent manner, because he himself has part in providence, providing for himself and for others. Hence, in him, too, there is a participation in eternal reason [the eternal law of God’s providence] through which he has a natural inclination to his due act and end. And the rational creature’s mode of participation in the eternal law is called natural law. […] Hence, the Psalmist (Psalm 4:6) says: “The light of Your countenance, Lord, is imprinted on us”—as if to say, the light of natural reason, by which we discern what is good and what is bad. This has to do with natural law (lex naturalis), which is nothing other than the imprint of God’s light within us. (ST I-II, q.91, a.2)

This is an important but complex text about what it means for a human individual to be a person, having mastery over his actions, leading oneself to the good of human life according to the moral rule of practical reason. The human creature is said to have in an active way part in divine providence and its law (providentiae particeps); that is to say, as persons we are able to govern ourselves and our life in the community, according to the rule of reason, which is based on the moral law (lex naturalis). This moral law, by which we are able to guide our lives in the light of what is good and what is bad, is a kind of imprint of God’s light in us. The human person, then, is marked (signatum) by the light of God, is imago Dei, and as such the bearer of the moral (natural) law. This connection with the natural law can also be seen in the Catholic personalism of, among others, Karol Wojtyla and Jacques Maritain. To be a person means to be responsive to the appeal of the moral law. 

The individuality of the human person

Another personalist motive is to be found in Thomas’ view of the special individuality proper to the human soul. Contemporary personalism tends to emphasise the uniqueness of the human person by distinguishing between person and individual. Being an individual as such is not enough to justify the status of a person. An individual, it is said, represents a single, countable unit in a homogeneous species, interchangeable with any other member of the species, whereas a person is characterised by his or her uniqueness and irreplaceability. For Thomas, as we have seen, a person is defined as an individual substance. In explaining this characteristic of individuality, Thomas does not refer to Aristotle’s theory of matter as principle of individuation. What is important for him is that substances, as opposed to accidents, have an individuality of their own, per se; this is the reason why, in combination with rational nature, they deserve the special name of person.

However, there is a complication in the case of human individuality. Human beings, according to Aristotelian philosophy, are composite substances in which the soul is the form received in the material body. For Thomas, the human soul is not only, like the soul of animals, the substantial form of the living body (forma corporis), but also a subsisting spiritual principle (in se subsistens), subject to the immaterial acts of the intellect and the will. The soul,  therefore, occupies a middle position between purely spiritual substances (angels) on the one hand and corporeal things on the other. According to Thomas, angels possess individuality by virtue of their form alone. Insofar as form is the principle of the species, it follows that, in the order of spiritual substances, each individual angel is a species of its own. The absence of matter precludes the multiplication of individuals within the same species. But material things are individualised because of their matter and are thus multiplied within the common unity of the species.

In the case of the human soul, the situation is more complex. There are many human individuals of the same species; this is because of the material body to which the soul is united. But the soul is not only individualised by the body, it also has an individuality of its own. The individuation of the soul, Thomas explains in his treatise De ente et essentia, “depends on the body as on the occasion of its beginning”, since the soul acquires its individuated existence in the body of which it is the act. But the individuation of the soul is not lost when the body is taken away. Once the soul has acquired an individuated existence as form of a body at the beginning of life, it remains individuated because it has absolute existence in itself. For this view Thomas refers to Avicenna: “That is why Avicenna says that the individuation of souls and their multiplication depend on the body for their beginning, but not for their end”.[5]

For Aquinas, the quotation from Avicenna has to do with a double aspect of human individuality. In so far as the soul has a being independent of the body, it has its own individuality, for being and individuality go together. We can call this individuality “personal individuality”, as opposed to the type of individuality with which a human being begins as an exemplar of the species. Avicenna’s text suggests that personal individuality, based on the existence of the soul, takes some time to develop fully. (The same idea can be found in Thomas’ Q.D. De anima a.1, a.2.)

The debate on the unity of the intellect

The primacy of the universal and the species over the individual, which has dominated intellectual thought since antiquity, plays a central role in the medieval debate on the unity of the intellect, a thesis defended by the Arab philosopher Averroes (Ibn Rushd) and his followers in the Latin West. In this debate, Thomas defends the personalist position of the integrity of the human person against the thesis that all individual members of the human species share a single intellect (intellectus possibilis). Although the word person is not used in the texts on this question, we see Thomas arguing against Averroes’ thesis by insisting on the integrity of the whole human person as the subject of acts. 

Averroes’ thesis of the unity of the intellect has its origins in a particular reading of Aristotle’s De anima. Aristotle describes the human intellect, which is an immaterial principle of knowledge, as separate from the body. It is assumed that the intellect must be receptive to the universal form of things; but this universal receptivity would, according to Averroes, preclude the multiplication of the one intellect over many human individuals. There must be a single operation of the intellect, common to all human individuals, which consists in apprehending the one universal form; to this intellectual knowledge of the universal form the many individuals relate themselves according to the corresponding sensory images they have.

The intellect, Thomas argues against Averroes, is the principle of the intellectual act of knowing. It is through the intellect that “we” understand, the concrete person, each with his or her own intellect. If the intellect were separate from individual human beings, one for all, it would follow that its operation is not an operation of this or that individual. It is no longer Socrates who understands, but some anonymous intellect. For Thomas, it is first of all a fact of experience that the individual person is the subject of the act of understanding (hic homo vel ille intelligat). And this means that the principle of the act of understanding, the possible intellect, must be multiplied according to the many individuals. But it does not follow that the intellect, as a faculty of a soul united to the body, would lose its universal openness to all forms, as if the intellect were compromised by the material body. Again, Thomas’ thesis is that the individuality of the soul, including the faculty of the intellect, is not dependent on the body. There is more to human individuality than the material multiplication of form and species.                             

Conclusion

Thomistic personalism is an interesting variety in contemporary personalist thought. It is generally accepted that Thomas himself is not a “personalist”. Nevertheless, his philosophy is an inspiring source for thinking about what it means to be a person. First of all, Thomas’ exposition of the Boethian definition of the person is relevant to contemporary personalism, especially because of the emphasis on “subsistence”, the person as the integral whole of a human individual standing in itself. Then we have pointed to a few implicit personalistic themes and arguments in Thomas: his view of the moral agency of the human creature, able to act freely of itself according to a moral rule; his view of the special individuality of the human soul, which has led us to speak of “personal individuality”; and finally this characteristic defence of the human individual in the debate on the unity of the intellect. There are, therefore, many reasons to consult the philosophy of Thomas in order to develop personalism in the context of contemporary thought.         

Literature

Thomas Williams, “What is Thomistic Personalism?”, Alpha Omega, VII, n.2, 2004, pp. 163-197.

Gilles Emery, O.P., “The Dignity of Being a Substance: Person, Subsistence, and Nature”, Nova et Vetera, vol.9, no. 4 (2011), pp. 991-1001.

Karol Wojtyla, “Thomistic Personalism”, in Person and Community: Selected Essays, vol.4 of Catholic Thought from Lublin, edited by Andrew N. Woznicki, New York: Peter Lang, 1993: pp. 165-75.

Horst Seidl, “The Concept of Person in St. Thomas Aquinas,” in The Thomist: A Speculative Quarterly Review, Vol 51, No 3, July 1987, pp. 435-460.

[1] See the informative article of Thomas Williams, “What is Thomistic Personalism?”, Alpha Omega, VII, n.2, 2004, pp. 163-197.

[2] ST I, q.29, a.3: “persona significat id quod est perfectissimum in tota natura, scilicet subsistens in rationali natura.” See also for a similar argument De potentia q.9, a.3. 

[3] See ScG IV, c.55; ST I-II, q.89, a.3/5. The term ‘dignitas’ is used here in a discriminating sense. For example, in the text from the Summa contra Gentiles, Thomas remarks that the “dignity of person adds to the praise of humility”.  Speaking of dignity in this sense differs from the way the expression dignitas personae is used in Catholic moral documents. See, for example, the document entitled Dignitas personae, published in 2008 by the Congregation for the Doctrine of the Faith, which gives a doctrinal instruction on certain embryonic ethical controversies.

[4] See for the order of the Summa theologiae, my book Aquinas on God (Ashgate, 2006).

[5] De ente et essentia, ch. 5;  the reference is to Avicenna, De anima V, cap. 3.