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Basic Concepts of Aquinas's Anthropology
Universidade de São Paulo
Translated into English by Diogo Rosas Gugisch
I have been asked to write this lecture in the form of a chapter – "Psychology" – for a textbook of a course on Aquinas's philosophy  . And the title "Psychology" may at first put off the modern student who immediately tends to associate the word “Psychology” with the science of modern psychologists.
In fact, thinking about Psychology today means thinking about counseling, therapy or intelligence or personality tests etc.
All this can be very interesting, but is not the Psychology which concerns us. What actually concerns us is another Psychology, that which must be understood in its old, classical sense: as that part of Philosophy which studies life, the living being, a being, therefore, with a soul. And the key word here is precisely “soul”, which in the classical tradition designates the principle of life. The Greek word for “soul” is psyché hence the name “Psycho-logy”, the study of the soul, the study of life. And this Psychology of life is basically concerned with the living being that is man.
Thus, if we want to find a name better suited to modern times for this topic, we could use the expressions “Philosophical Anthropology” or “Philosophy of the living beings” instead of “Psychology”, for those names indicate the study of man and living beings.
We call attention to the fact that throughout this study there will be other words whose classical meaning does not coincide with their modern meaning: “potency”, “act”, “matter”, “form”, “movement” and “spontaneity”.
2. Aristotle, landmark of “Psychology”
A quick glance at the program of our course – which mentions such concepts as “vital principle”, “body and soul” and the several faculties of the soul – should be enough to show that it points not only to Psychology as a part of Philosophy but that it also implies a theoretical background necessary for our study: the doctrine presented by Aristotle – IV century b.C. – in his treatise named Peri Psyché – On the Soul.
The Aristotelian doctrine has become part of the classical Western tradition, a tradition in which another great philosopher, Thomas Aquinas – XIII century A.D – also wrote a famous work entitled De Anima, On the Soul, a commentary on Aristotle’s work.
Thus, in this chapter we shall study the fundamental concepts of Psychology, “Psychology” here understood as the study of life (and, particularly, as philosophical anthropology) in the classical frame of Aristotle and Thomas Aquinas. Aristotle’s “Psychology” emerged as a reaction of equilibrium and moderation against the exaggerated spiritualism of Plato’s anthropology – which has been re-fashioned over and over again both in the East and in the West. (parei aqui)
This Platonic spiritualism is a radically dualistic assumption vis-a-vis our main question: “What is man?” Plato puts spirit and matter as two juxtaposed realities, disjuncted, loosely and extrinsically connected in man. For man, according to Plato, is primarily spirit - and the body, according to this point of view, is something like the prison of the spirit  .
From the Aristotelian point of view, this platonic dualism goes against the intrinsic substantial unity of man when it despises the material dimension of human beings and exaggerates the separation between body and spirit. And it is this unity which precisely entitles each man, each one of us, to utter the pronoun “I”, comprising both spirit and body.
To the Platonists man is essentially spirit in extrinsic union with matter: matter is not part of the specifically human reality. For Aristotle, on the other hand, there is in man an intrinsic union between spirit and matter.
An extrinsic union is the kind of union that takes place, for instance, between a man and his clothes; while an intrinsic union is that which takes place, for instance, between an object and its color (there is no color without the object nor object without color).
From the Aristotelian point of view, our main question, “What is man?”, presents itself as a difficult and challenging one. And this because human reality presents itself to the philosopher as a very complex phenomenon, integrating in itself spirit and matter in harmonic unity.
Thus, on the one hand, corporal dimension is fully recognized by Aristotle as a part of human nature: we have the evident fact that man is an animal, sharing a material dimension – his body, his chemical constitution – with the other animals  .
However, on the other hand, we have the equally vehement statement of a transcendence from the merely biological sphere: certain traits which have been classically called spiritual, traits connected – as we shall later see – with the two spiritual faculties of the human soul: intelligence and will.
3. Aristotle and cosmic unity: from mineral to man.
The Aristotelian frame, the so called Aristotelian realism – as opposed to several forms of philosophical idealism – is considered to be a balanced dualism, presenting a great unity in its theoretical formulation, a unity centered on the concept of “soul”.
It is very important to emphasize such a unity. To Aristotle and Thomas Aquinas the philosophy of man – the “Philosophical Anthropology” – is but another chapter, an extension of Psychology in general, of the philosophy of living beings in general, and this, in its turn, merely follows the analysis of material beings in general. Spiritual reality is plainly stated, but intimately connected to matter.
Aristotle’s philosophy thus acknowledges an impressive unity in the material world: the same structure of philosophical analysis is applied to all living beings as well as to man, who is a spiritual being.
4. Aristotelian hylomorphism: potency-act, matter-form.
In the present work it is not our intention to examine in depth the philosophical concepts we are dealing with. Nonetheless, such concepts are worth mentioning, even if we have to do it rather cursorily. They are: potency and act, matter and form – which, on the level we are presently working in, the level of the composition of the living beings, ought to be called prime matter and substantial form, even if we sometimes refer to them simply as matter and form.
Let us begin with potency and act. Potency and act are two fundamental and distinct modes of being. As fundamental modes of being they are, strictly speaking, undefinable.
Aristotle merely describes them: potency is the possibility, the potentiality of becoming being in act. The being-in-act is what really is, whereas the being-in-potency may become being-in-act. The classical example is the seed – that is potency –, which may become a tree – the real tree being the act present in potency, in the seed’s potentiality.
We may find some traces of the Aristotelian use of the word “act” even nowadays. When, for instance, we say that something is “exact” what we mean is that our subject is ex-actu, ex- from / -actu reality.
When analyzing the living being, as well as the physical being in general, Aristotle uses the terms act/potency under the formulation matter/form – which in the present text, as we have previously said, shall always mean prime matter and substantial form.
We should not assume that the word “matter” and the word “form” have the same meaning to which we assign them today. These words must be understood in the framework of Aristotle’s philosophy of nature, and it is not by chance that it bears the name of the theory of hylomorphism – hylomorphism means literally the theory of matter-form: hilé means matter in Greek, while morfé means form. Hilomorphysm: matter-form.
Thus, prime matter should be understood simply as potentiality, as the pure possibility of being a physical being. A potency actualized through the union with the act that substantial form is.
Thus, any physical being, for example a diamond, is made of matter and form intrinsically united.
To sum up, we could say that hylomorphism, Aristotle’s philosophy of nature, contends that every physical being is composed of prime matter and substantial form: prime matter is pure potency of being a physical being and substantial form is the first act, the fundamental act that determines the actualization of that potency.
Thus, if our diamond is a physical being, it is because it has the possibility, the potentiality of being a diamond – and so all physical beings have a prime matter, the potentiality of being a physical being. The substantial form actualizes this potentiality of the prime matter: that component that makes a diamond a diamond, instead of a cat or an orchid.
The diamond, the cat, the orchid and man have something in common, they are all physical beings, therefore constituted of that pure indeterminate possibility which prime matter is. But their form distinguishes them from each other and it is precisely the form that makes them what they are: the diamond is a diamond because it has the substantial form of a diamond, the cat is the cat because it has the substantial form of a cat and the same applies to man.
On this point, a short explanation is necessary as to how philosophy developed these concepts. In analyzing material reality, Aristotle’s point of departure was the experience of the phenomena of every being’s substantial unity  .
Another point of departure of Aristotle's was the reality of substantial changes, those "deeper" changes in which what changes is not this or that accidental quality of the subject (the man who got taller, fatter or changed his position in space) but the subject itself: a thing X ceases to be what it was and becomes an altogether different thing Y, for example, a piece of wood after being consumed by fire ceases to be what it was – wood – and becomes another thing – ashes.
In such cases of substantial change, the new being Y did not come out of nothing, it came out of X, and the being X was not reduced to nothing, it became Y.
When we examine examples of substantial change we see that there is something that remains as well as something that changes – which shows that the substance is a composite of two elements, one that changes and one that remains. What is left is the prime matter, actualized in each case by a determinant act on this potency that makes X to be X and Y to be Y: the substantial form.
Prime matter and substantial form intrinsically united produce the substance of the physical being. A diamond is a physical being because of matter and it is a diamond because of its form.
Prime matter is the weak mode of being called potency; substantial form, on the other hand, is the decisive component in the constitution of a being: a stone is a stone because it has the form a stone and a man is a man because he has the form of a man.
Thus, all physical beings are composed of an intrinsic union between matter and form. Aristotle and Thomas Aquinas hold such a unitary view of the cosmos because they employ the same concept of matter and form to indicate both the substantial composition of a stone and of a man, who is a spiritual being.
5. The soul as the substantial form of the living being.
In this context, it is very easy to understand the central concept of Psychology, the concept of soul. To Aristotle and Thomas Aquinas, soul means simply form: the substantial form of the living being.
It is, of course, a very special form – bearing, as a consequence, a special name – but it is nonetheless a form.
We can say that the soul is a form, but a very special one because it acts, it in-forms the living being, constituting the principle of life.
6. Life: spontaneity and immanence in the operations.
We wish to say a word here concerning the philosophical definition of life and of living being.
How can life be defined? Certainly it is something related to movement -"movement" understood here in the broader sense employed in antiquity, meaning not only the changing of place but in fact of any change in general. However, it may be objected that movement is not a trait peculiar to life only; it is a constant in the cosmos. The response of Classical philosophy to this objection is the statement that what is peculiar to life is the spontaneity and immanence in movement.
Spontaneity is here understood as the lack of exterior mechanical determination of life’s movements – at least of the greater part of them. To say that spontaneity is a fundamental characteristic of life, a fundamental characteristic of the living being’s operations, is tantamount to saying that the movement and the changes of the living being have also an internal pole; the living being is, if we can say so, the protagonist of these changes.
Let us take, for instance, the example of the growth of a living being. Such a growth is very different from a mere agglomeration of matter by juxtaposition (for example the “growth” of a dune): the growth of the living being comes from the inside of the subject, its principle is located in the subject itself, and it is in this sense that we talk about the spontaneity of the movement of the living being.
The other characteristic trait, immanence, indicates the fact that the end of the subject’s movements is the subject itself. There are, in the living being, operations that not only have their principles in the living being (spontaneity), but that have and end in him. Such is the case of nutrition. The nutrition process ends by the assimilation, the transformation in the living being itself of that exterior object that was fed to him.
Both spontaneity and immanence mean a special degree of inwardness in the living being, by which he nurtures himself, he moves himself etc.
This special way of interacting with the outside world from an inwardness comes from the singularity of the living being’s form, and that is the reason why the form of living beings also has a special name: soul. Hence, we can talk about a vegetal soul, the soul of a fern, the soul of an ant, the soul of a dog and the soul of a human being (in this case it is a spiritual soul).
The soul (like all the substantial forms) is a principle of the substantial composition of living beings. To put it in a better way, it is a co-principle – intrinsically united with the other co-principle, prime matter. It is through the soul that the living being is constituted and integrated as such, and it [the soul] is also the first source of its actions and operations.
These are the two definitions of soul presented by Aristotle and Thomas Aquinas.
1st. definition: The soul is the first act of the organized natural body. (Thomas Aquinas De Anima II, 1, 412, a 27, b.5).
This definition plainly states that the soul is the substantial form of the living being: the active principle that constitutes the unity and the being of the living being.
2nd. definition: The soul is that by which we first live, feel, move and understand... (Thomas Aquinas De Anima II, 2, 414, a 12).
This second definition also presents the soul as substantial form, but in the present case the stress is laid on the substantial form as the radical source of the subject’s operations. A dog bites or barks because he has a mouth, but in the end he does so because he is alive, because he has a substantial form, the soul of a dog.
7. The soul and its potencies: factors in the living being’s operations.
The soul does not operate directly and that is the reason why Aristotle says: “The soul is that by which we first live, feel, move (...)”. "First", means here that it is not the soul that directly sees, walks or knows, but that the living being does such things through the faculties of the soul (the visual faculty, the motor faculty – faculties that are associated to the organs of the body).
Thus, it is necessary to distinguish the several factors involved in any given operation of a living being. The same living being may be performing such and such an operation or he may be not, however he is continuously alive, he is being informed by the soul. Hence it is necessary to distinguish the soul (substantial, always working) from its faculties (that may or may not be working). The visual or the motor faculties are not always working – for instance when I am asleep – but the soul, the vital principle, is always present as the substantial form of the living being.
We therefore rank the several factors involved in the living being’s operations.
1) The living being itself. The subject, for example Joe, who performs this or that operation (hearing or seeing, for instance).
2) The soul. If Joe performs this or that operation it is because he is a living being, that is, because he has a soul. If he were a stone he would not be able to see or hear anything.
3) The faculties of the soul. For it is not the soul in itself that sees, hears, walks etc. It performs these operations through its faculties. The soul possesses a visual faculty, which performs the act of seeing; the auditive faculty performs the act of hearing, etc.
4) The acts of the faculties. We know that the soul possesses different faculties precisely because the living being performs different acts: seeing is different from hearing; thinking is different from willing, etc.
5) The objects of the acts (the "formal object"). We can say that if the act of seeing is different from the act of hearing that is because their objects are different: the object of the act of seeing is color; the object of the act of hearing is sound.
6) The material object. It is clear that the same material object – a bonfire, for instance – can be apprehended by several faculties, but each faculty apprehends its by means of its own formal object (the visual faculty apprehends the color of the fire, the auditive faculty apprehends its cracking, the olfactory faculty apprehends the smell of smoke, etc.).
8. The three degrees of life.
Life, as we have been saying, is the capacity to perform spontaneous and immanent operations, that is, from the subject himself and ending in the subject himself.
Such spontaneity and immanence admit three degrees and hence determine three degrees of life, namely, the vegetative life (the one that pertains to the plants), the sensitive life (the one that pertains to the animals) and intellective life (the one that pertains to man).
Three degrees of life correspond to three degrees of spontaneity and immanence in the performance of the living being’s operations. They also correspond to three kinds of souls: the vegetative soul, the sensitive soul and the intellective soul.
The first degree of life – the vegetative life – has only a very small degree of spontaneity and immanence: the vegetable possesses only the mere execution of the operations of growing, feeding and breeding, for example.
It should be noted that, as we climb the ladder of life and the soul grows in immanence and spontaneity there is also a widening in the range of its relationships: from the limited environment that surrounds a plant to the boundless world of the human spirit.
The soul in each degree of life is one and performs all the functions of the lesser degrees: the spiritual soul, responsible for the gentle poetry that a poet composes is the same one that is responsible for the poet’s digestion and the circulation of his blood.
Beyond the mere performance of the characteristic operations of the vegetative life, the sensitive soul of the animals is also responsible for sensitive knowledge: the cognitive apprehension of those concrete realities that surround it. Thus, it is through knowledge – which is clearly an important factor in its operations – that the animal possesses more spontaneity and immanence than the vegetable.
Thus, the level of life of animals is superior to that of plants: animals are in a fuller possession of their operations and of their interaction with the environment because they are able to feel, which means that they are able to know concrete and particular realities.
These faculties of feeling, or faculties of knowledge of sensible realities are the senses: vision, hearing etc.  . They are present in animals as well as in man. The animal’s knowledge, however, does not go beyond the realm of the sensible: this color, this smell, this sound...
9. The intellective life: man and his spiritual potencies. The first intellectual potency: intelligence.
In the case of man, which is the case of the intellective life, the soul performs not only the higher operations but all the operations pertaining to the lesser degrees of life.
Thus, the human soul is responsible for the operations of the faculties of the vegetative life – for example circulation of blood, digestion, etc. -, the sensitive life – for example sensible knowledge – and besides all that we have here the irruption of a new dimension: the dimension of the spirit.
The human soul possesses two spiritual faculties: intelligence and will. We shall begin with intelligence. While sensible knowledge deals with particular and concrete realities, human intelligence transcends the realm of the particular and the material and is capable of dealing with the universal. Geometry, as a human intellectual knowledge, is not concerned with this particular paper triangle that I have here before my eyes; it is concerned with abstract triangles. And it states: “The sum of the internal angles of the triangle is equal to two straight angles.”
We must emphasize the abstract and universal character of this statement: the triangle’s color does not matter, the intelligence being concerned with “the triangle”. And for “the triangle”: “The sum of the internal angles is equal to two straight angles.” Medicine studies for example hepatology, it studies “the liver” no matter whose liver it is.
This capacity that the intelligence has to apprehend the universal and the abstract unfolds a boundless world for knowledge, since it is not limited to the surrounding reality, but it reaches all being. It is precisely this unfolding to the wholeness of reality that is called spirit.
Spirit – according to the classical definition – is the capacity to relate to the totality of reality. Hence the fact that Thomas Aquinas sometimes quoted this phrase from Aristotle: "Anima est quodammodo omnia", "The human soul, being spiritual is, in a certain way, everything.”; it means that the soul is capable of relating all things, by knowing them.
Based on this definition of intelligence as man’s faculty of spiritual knowledge we can shed new lights on the basic concepts of Aristotle’s and Aquinas’s Psychology.
Against all dualism that tends to exaggerate the separation between spiritual soul and matter in man, Thomas Aquinas emphasizes the intrinsic union of both principles: the spiritual soul as form demands integration with matter. We may contemplate, for instance, the example of psychosomatic diseases: the relation between being dissatisfied and having an ulcer. The most striking example, however, of this integration may be found in the discussion of the specific object of human intelligence.
As we have already said, the soul does not operate directly on the world, it does so by means of its faculties. Now, every faculty of the soul is proportionate to its object: the auditive faculty hears no colors, the visual faculty sees no smells.
To say that intelligence is a spiritual faculty is tantamount to saying that its realm of relationships is the totality of being: all visible and invisible things are intelligible, they dovetail in with the intelligence. However, the relationship between human intelligence and its objects is not a uniform relation. Among all beings and modes of being, there are some which are more directly and immediately accessible to intelligence.
That is what Thomas Aquinas calls the specific object of a faculty, that dimension of reality that is better adjusted to the faculty, or more precisely, it is the faculty that is adjusted to reality. It does not mean that the faculty cannot apprehend other objects, but the obiectum proprium, the proper object is always the central element of every apprehension: if through our vision we apprehend number and movement – we see, for instance, seven people running – that is because we see the color, which is the proper object of vision. Well, the proper object of human intelligence – the faculty of a spiritual form connected to matter – is abstraction: the proper objects of human intelligence are the abstract essences of sensitive things.
"The proper object of the human intellect, which is united to a body, is nature existing in corporeal matter, and through such natures of visible things it rises even to some knowledge of invisible things.” (S. Th. I, 84, 7).
In this statement we can find the ontological nature of man. This point of view holds that even the most spiritual realities can only be grasped by man through sensitive reality. “Everything we know in this life – proceeds Thomas Aquinas – we know by comparison with natural sensitive things”. This is the reason why the extensive and metaphorical sense can be found in our language much more intensely than we might at first assume.
Against all dualism that tends to exaggerate the separation between spiritual soul and matter in man, Thomas Aquinas emphasizes the intrinsic union and the mutual coordination of both principles. Against Plato’s “spiritualism”, Thomas Aquinas states: “It is clear that man is not a soul only, but something composed of soul and body” (Summa Theologica I, 75, 4).
Thomas Aquinas understands the body to be such an essential part of man’s reality that this union projects itself into that spiritual operation that knowledge is: “The soul needs the body to achieve its end, inasmuch as that it is through the body that it gains perfection in knowledge and in virtue.” (C.G. 3, 144.).
10. The second spiritual faculty: will.
But man – just like all other animals – is not only intelligence. There is in him a dynamic, a tendency towards actual possession – opposed to the merely cognoscitive possession – of objects, and this is precisely what is classically named appetite.
An animal, a dog, for instance, not only knows a bone – this knowledge, in the case of the animal, does not go beyond the sensitive realm – but he also tends to the actual possession of the bone: that is what we called appetite, an appetite that in animals is also limited to the sensitive realm.
Appetite is the tendency seek good (seek what our knowledge presents as good) and shun evil (shun what our knowledge presents as evil).
Of course the appetite is connected to knowledge, it comes from knowledge. If the dog tries to eat the bone that is because it [the dog] has smelled the bone in the first place. Now, in the same way that there is in man, beside a sensitive knowledge, an intellectual knowledge; and beside our sensitive appetite we also possesses another appetitive faculty which is linked to intellectual knowledge: this faculty is called will.
Thus, the will is the spiritual appetitive faculty, the appetite that comes from intellectual knowledge. This is the reason why we are motivated not only by concrete realities, for example a prize, but also by “justice”, “dignity”, “human rights”, “honor”, etc. If the formal object of all appetite is the good, the formal appetite of the will, as intellectual appetite, is the good intellectually known.
11. Summary and Conclusions.
To terminate we present in some topics the most important points that have been discussed:
1. "Psychology" as a part of philosophy does not correspond to the science of the modern “psychologists”, but rather to the philosophical study of the soul and life – the word “psychology” etymologically means “study of the soul”.
2. To the anthropology of Aristotle and Thomas Aquinas there is an intrinsic union and a harmonious relationship between the spiritual and material dimensions in man.
3. There are two fundamental modes of being: being in act and being in potency. The hylomorphic doctrine holds the substantial union of two co-principles: prime matter (which is potency) and substantial form (which is act).
4. Prime matter is sheer potency of being a physical being; substantial form is the first act that determines that potency. It is the form that makes man a man.
5. The soul is the substantial form of the living being. Hence its definition as “first act of the organized natural body” or as “radical source of the operations of the living being”.
6. Life’s main features are spontaneity and immanence in its operations: the living being’s operations find in the living being itself their principle and their end.
7. The same soul is responsible for the functions of vegetative, sensitive and intellective life in man. There are three degrees of life – vegetative, sensitive and intellective – which correspond to the three degrees of spontaneity and immanence.
8. The soul operates through its faculties and not directly.
9. In any given operation of a living being, we can distinguish: the subject himself, his soul, the faculties of the soul, the acts of each faculty, the formal object of each act as well as its material object.
10. The vegetative life is responsible only for the execution of the operations; animals, however, have a sensitive knowledge as well, and man, in addition to all this, possesses spirit.
11. A being is spiritual if it is able to engage in relationships with everything that is.
12. Human intelligence transcends the sensible and concrete realm and reaches the abstract and the universal. That is the reason why it is a spiritual faculty.
13. The proper object of human intelligence is the abstract essence of sensitive things. For instance, the idea of the triangle is the proper object of intelligence, abstraction taken from the multitude of particular and concrete triangles.
14. Besides the cognoscitive dimension, animals also have the appetitive dimension, a dynamic dimension that tends towards the union with what is recognized as good.
15. The will is the spiritual appetitive faculty of man. The will follows the intelligence.
 Filosofia, published (also available on cassette tapes) by the Instituto Brasileiro de Direito Constitucional, São Paulo, 1997.
 Plato even admits the existence of three souls in man, and they correspond to the three functions of the same soul according to Aristotle.
 The strength of the Aristotelian-Thomist realism is demonstrated by the fact that the phrase “other animals” in its various Latin forms alia animalia, aliis animalibus etc. is found about four hundred times in Thomas Aquinas’s works.
 Such a unity is particularly clear in living beings, which any person can experience himself, hence we say: “I”, “you”, “he” thus indicating the substantial unity of every human being.
 . Classical philosophy divides the faculties of the sensible knowledge, our senses, in external senses (basically our traditional five senses) and internal senses, which are four: common sense, imagination, memory and estimative faculty.