An essay of reflection on Book III of Aristotle’s Nicomachean Ethics.
Introduction
Paragraph 475 of the Catechism of the Catholic Church presents one of the densest formulations of Christology: the confession that Christ possesses two wills, one divine and one human — which do not oppose each other, but cooperate in perfect harmony. The text recalls the definition of the Sixth Ecumenical Council of Constantinople III (681), which condemned the Monothelite heresy, according to which Christ had only one will. The Church affirmed with clarity: just as Christ has two natures, divine and human, He also has two operations and two wills, preserving the integrity of His humanity without dilution.
This formulation, however, raises a question: how can a single subject, the Person of the Word, have two wills without falling into internal dichotomy, as if Christ were divided? The problem requires recourse to the concept of will in Aristotle, to the reflection of the Apostle Paul on the inner struggle of man, to the development of Saint Augustine on freedom, and to the Thomistic systematisation which distinguishes the powers of nature and the unity of the person.
This essay therefore seeks to develop a broad understanding of the mystery of Christ’s double will, tracing the philosophical and theological tradition and showing why the coexistence of these two wills does not generate contradiction but plenitude.
The notion of will in Aristotle
Aristotle did not understand the will as a simple momentary desire or as a psychological “want”, as we are often inclined to think today. For him, the will has its root in the rational structure of the human being and cannot be reduced to a passing emotion.
More than this, the will is conceived as a form of orexis (appetite), that is, the natural tendency of man towards the perceived good. In this sense, it is inseparably linked to intelligence: one does not desire anything except what one judges in some way to be good. For this reason, he distinguishes between different forms of appetite.
The first form of appetite is epithymia, or concupiscible desire. It is manifested as the immediate impulse towards sensible pleasures — for example, eating when hungry or lying down to rest when tired. This type of desire is not evil in itself, but it has a limit: it seeks only particular and transitory goods. Precisely because it is directed to the immediate, it can easily become disordered, giving rise to vices such as gluttony or sloth, when pleasure or rest are sought above higher goods. At this lower level of appetite lies human concupiscence, that is, the disordered inclination towards sensible pleasure.
The second form of appetite is thymos, or irascible desire. Unlike epithymia, it is not limited to immediate pleasure, but is directed towards overcoming obstacles and resisting evil. It is what awakens courage in the face of danger, the disposition to face challenges and perseverance in difficulties.
Thymos represents a higher level, because it is not restricted to pleasure but involves effort and struggle. Yet when not guided by reason, it can become disordered and degenerate into uncontrolled anger, pride or vanity — vices which arise when the energy of struggle is used not for the true good but for personal triumph or the exaltation of the ego.
The third form of appetite is boulesis, rational desire in the strict sense. Here, the will is directed to the ultimate end grasped by reason, that is, to the good which is not sought merely as useful or pleasant, but as worthy in itself. At this level is found will in the proper sense.
Boulesis makes ethical life possible, for it subordinates the immediate desires of epithymia and the passions of thymosto a higher order, guided by intelligence. Thus, it directs the human being towards his telos, the ultimate end which gives meaning and unity to the whole of moral life.
This distinction shows that will is not a blind instinct but a hierarchy of desires, which ranges from the most immediate to the highest. The fully virtuous human being is the one who manages to harmonise epithymia and thymos under the guidance of boulesis, that is, who orders his partial desires to the ultimate end. Ethical life, in Aristotle, consists precisely in finding this harmony, avoiding that the lower appetites impose themselves against reason.
How is this concept seen in Christ?
Applying this scheme to Christ, we see that He, in assuming human nature, also assumed epithymia (hunger, thirst, pain), thymos (courage in the face of suffering) and boulesis (rational desire for the good). He therefore possesses a complete human will, experiencing all the legitimate inclinations of our nature. But, being the eternal Word, He also possesses the divine will, which is the very essence of God in act: the eternal and immutable willing of the absolute Good.
Here the question arises: would Christ not be inwardly divided, as if the epithymia or thymos of His human will could oppose the divine boulesis? Here lies the decisive point: no, because in Christ all these human dimensions were assumed without the wound of sin. His epithymia (sensible desire) was never disordered; His thymos (strength to resist) never degenerated into anger or pride; His boulesis (rational appetite) never closed in on a lesser good. His human will is always ordered to the divine, in perfect harmony.
Thus, the Aristotelian notion of will prepares the Christian understanding: Christ has two wills, but they are not divided. The human will, structured according to epithymia, thymos and boulesis, is full and real; but it is also perfectly ordered to the divine will, so that there is no opposition but harmonious cooperation.
The tension of will in Aristotle and Paul
Aristotle’s reflection on the levels of human appetite sheds light on the complexity of willing. The philosopher perceives that man does not desire uniformly, but according to diverse dimensions: the immediate impulse of pleasure, the energy of struggle and the rational orientation towards the true good. This structure points to an inner hierarchy in which reason must guide the lower inclinations so that moral life may reach its fulfilment.
Paul, in Romans 7, describes this same reality in another key: the struggle between the willing of the spirit and the willing of the flesh. The apostle recognises: “I want to do what is good, but I do not do it; the evil I do not want to do, this I keep on doing” (Rom 7:19). Here the inner dichotomy is manifested: man experiences, at the same time, attraction to the good and the force of sin which drags him to evil. While Aristotle understands disorder as a failure in the ordering of reason over appetites, Paul reveals the deeper wound caused by original sin: the will no longer governs fully, but finds within itself a division which only grace can heal.
This Pauline reading inaugurates a decisive theme for the whole Christian tradition: the tension between human freedom and slavery to sin. For Aristotle, reason has in itself the capacity to order; for Paul, this capacity is weakened and needs to be restored by Christ, the “new Adam”. It is He who, through His obedience, reconciles man with God and reorders the wounded will.
Applying this to the mystery of the double will in Christ, we see the contrast. In us, the will is divided; in Christ, it is not. His human will, though subject to natural passions such as hunger, thirst and pain, never opposes the divine. The episode of Gethsemane is the paradigmatic example:
“Father, if you are willing, take this cup from me; yet not my will, but yours be done” (Lk 22:42).
In this prayer, two wills are distinguished: the human, which naturally recoils before suffering, and the divine, which wills redemption through the cross. But there is no rupture: the human will of Christ freely submits to the divine, realising in perfect obedience what Adam, and with him all humanity, failed to accomplish.
The same appears symbolically in the dialogue with the Samaritan woman at the well (Jn 4). Christ begins from a human need — thirst and the request for water — to lead the woman to the deeper desire: the living water which definitively satisfies. Thus, natural will becomes the meeting point with the divine will.
While Aristotle helps us to understand the natural structure of human willing, Paul reveals the spiritual wound which runs through that structure. And in Christ, we find plenitude: the perfect unity between reason and desire, between humanity and divinity, which makes it possible for man, by grace, to overcome the inner division and walk towards the ultimate good. And this is why Paul proves deeper than Aristotle. The Greek philosopher describes with precision the structure of human willing, but does not indicate how to attain interior unity in its fullness. Paul, on the contrary, points to the answer: plenitude is Christ. In Him, human nature does not need to be denied or abandoned, but assumed and redeemed. It is precisely by remaining human — with our needs, desires and limits — that we find true happiness, for in Christ the will is reconciled with the ultimate good and freedom is fully restored.
Augustine and the philosophy of will
Later, Augustine takes up Paul’s intuition and develops it into a true philosophy of will. For him, voluntas is the core of freedom, but a wounded freedom. Sin does not destroy the will, but disorders it: it continues to seek the good, but clings to lesser goods, mistaking them for the supreme Good.
In this horizon, he distinguishes between two modes of freedom:
The libertas maior, full freedom, which consists in choosing the good out of love for God; and the libertas minor, formal freedom of choice, but inclined to evil, marked by the disorder of sin.
In the Confessions, Augustine recognises within himself the struggle between two wills: the old and the new, the carnal and the spiritual. This division translates the human drama described by Paul in Romans 7: wanting the good, but experiencing the contrary force of sin.
In the case of Christ, however, this division does not exist. His human will is neither wounded nor disordered. His libertas is full: He is truly free because His human will is perfectly united to the divine, always directed to the supreme Good without deviation.
Thomas Aquinas and scholastic systematisation
Thomas Aquinas offers the most precise formulation when treating the mystery of will in Christ. For him, Christ possesses two natures, divine and human, and since will is a power of rational nature, it follows that in Him there are also two wills: the divine will, proper to the divine nature, and the human will, proper to the human nature assumed.
Nevertheless, in Christ there is one single Person: the Word. Therefore, the two wills do not belong to “two selves”, but to two distinct natures exercised by one single subject. The human will is not abolished, but fully subordinated to the divine. This subordination does not mean servility, but perfection: the human will attains its full freedom precisely by consenting to the divine willing.
Moreover, Thomas explains that Christ’s human will, illuminated by the beatific vision from the moment of the Incarnation, cannot sin or rebel. Thus, although He legitimately experiences the natural inclination to avoid pain, that will always remains ordered to the consent of the divine will. In this perfect consent is revealed the true freedom of Christ and, at the same time, the restoration of human freedom.
There is, therefore, not dichotomy but symphony: the human will does not oppose the divine because both have the same ultimate object, the good and salvation. Thomas uses the analogy of the union between soul and body: each has distinct operations, but together they constitute a single person. So also in Christ, the two wills operate harmoniously, in perfect consonance.