The relationship between our body and our soul according to st. Thomas Aquinas is the aristotelian unity between form and matter. So when one dies, in a way the soul is incomplete without the body and awaits for its resurrection. St Thomas Aquinas follows Aristotle’s hylomorphism: body is the matter, soul is the substantial form. They don’t make two “things” joined together, but one living being. Because of that, Thomas insists the soul isn’t “me” in its entirety. It’s the principle that gives life and makes this body human, but without the body, it’s in an unnatural, incomplete state. The separated soul after death survives (because of its immaterial powers, intellect and will), yet it’s not fully the human person. He calls this an “incomplete substance” (Summa Theologiae I, q. 75, a. 4). The soul looks forward to being reunited with its body at the resurrection, when the whole person is restored. Here are a few key passages where Thomas himself makes the point:
1. On the soul as the form of the body
“The soul is related to the body as its form… The soul, since it is part of the human species, is not the whole man; and my soul is not I. Hence, although the soul may be said to be man’s form, yet man is not said to be a soul, but a being composed of soul and body.” (Summa Theologiae I, q. 75, a. 4, ad 2) Latin & English here
2. On the soul’s natural state
“Since the soul is part of the human body, it is not a complete substance, but part of a complete substance… Therefore, although the soul may exist without the body, this is against its nature; and so it is not a perfect species.” (ST I, q. 76, a. 1, ad 6) Full text
3. On the soul’s survival after death
“The human soul has an operation apart from the body, namely understanding; and therefore it is subsistent. Yet it is naturally ordained to be united with the body as its form. Hence, although it may subsist apart from the body, it is not its natural state.” (ST I, q. 75, a. 2) Text here
So: the human soul is immortal and subsists, but it is only fully itself in union with the body. That’s why resurrection is not just a bonus, but the restoration of the person in wholeness.
Thomas holds the tension carefully:
On the one hand, the soul can enjoy the beatific vision without the body, because its highest power—intellect and will—do not depend on bodily organs. That’s why the saints in heaven already see God face to face, even before the resurrection. On the other hand, Thomas insists this is not the soul’s natural state, but a provisional one. The soul is made to animate a body, and without it something of human wholeness is missing. He says “The soul, since it is part of the human body, is not the whole man, and therefore the soul separated from the body is not the complete human species. Thus, although the soul may attain to beatitude in respect of what belongs to it, still, something will be lacking to its beatitude until the body is restored.” (Summa Theologiae Supplement, q. 92, a. 1, ad 3) Text here
He even says the soul’s joy will be incomplete until it is reunited with the body, because perfect happiness belongs to the complete human nature. That’s why the resurrection of the body is essential: it’s the full consummation of beatitude, not an afterthought. Here’s how Thomas lays it out, step by step.
1. Death and separation
At death, the body corrupts, but the soul endures because it is immaterial and subsistent. However, it exists in an unnatural state: not a whole person, only the form without its matter (ST I, q. 75, a. 2–4).
2. Particular judgment
Immediately after death, each soul undergoes what Thomas calls the “particular judgment,” where its eternal destiny is revealed: heaven (possibly via purgatory), or hell (ST Supplement, q. 69, a. 2).
3. The beatific vision (for the blessed)
The souls of the just, once purified, enjoy the direct vision of God. Their intellect and will—their highest powers—are fully satisfied in this vision (ST I-II, q. 3, a. 4). Yet, this blessedness is incomplete:
“Something will be lacking to their beatitude until they recover their bodies” (ST Suppl., q. 92, a. 1).
4. Waiting for resurrection
Meanwhile, souls await the resurrection of the body. Aquinas says they even desire this reunion, because nature is ordered to soul-body unity (ST Suppl., q. 70, a. 3).
5. The general resurrection
At the end of time, God reunites each soul with its body, now glorified for the blessed, or corruptible for the damned (ST Suppl., q. 79–85).
6. Final consummation
Only then is the human being complete again. The blessed enjoy perfect happiness with soul and body together, and their joy is actually greater because they can participate in God not only spiritually but bodily (ST Suppl., q. 93, a. 4).
So, for Aquinas:
• The soul can subsist and be blessed on its own.
• But “I” am not fully myself until my body rises.
• Resurrection is the seal of God’s plan, restoring the whole person for eternity.
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The Catechism of the Catholic Church (1992) basically picks up Thomas’s thread and restates it for today.
1. Soul–body unity
“The human body shares in the dignity of ‘the image of God’: it is a human body precisely because it is animated by the spiritual soul, and it is the whole human person who is intended to become, in the body of Christ, a temple of the Spirit” (CCC 364). This echoes Aquinas’s hylomorphic unity.
2. The soul as form of the body
“The unity of soul and body is so profound that one has to consider the soul to be the ‘form’ of the body” (CCC 365). That’s almost a direct lift from ST I, q. 76, a. 1.
3. State after death
The Catechism confirms the soul’s survival: “The Church teaches that every spiritual soul is immortal: it does not perish when it separates from the body at death” (CCC 366). Like Thomas, it stresses that the soul’s separation is not a final state, but provisional.
4. Particular judgment and heaven/hell/purgatory
“Each man receives his eternal retribution in his immortal soul at the very moment of his death” (CCC 1022). This lines up with Thomas’s teaching on the particular judgment.
5. Incompleteness until resurrection
Even souls in heaven await something more: “The term ‘heaven’ does not mean only a place but a state of definitive happiness. … This perfect life with the Most Holy Trinity … constitutes the Church of heaven” (CCC 1024). Yet, just two paragraphs later, the Catechism adds: “The resurrection of the dead will bring the definitive fulfilment of this happiness” (CCC 1027). That matches Aquinas’s insistence that beatitude is incomplete until body and soul are reunited.
6. The general resurrection
“The resurrection of the flesh means not only that the immortal soul will live on after death, but that even our ‘mortal body’ will come to life again” (CCC 990). “We believe in the true resurrection of this flesh that we now possess” (CCC 1017). This is Thomas’s resurrectio carnis, perfected in glory for the blessed.
In short:
• Aquinas’s hylomorphism undergirds the Catechism’s anthropology.
• The Catechism confirms his twofold claim: the soul is immortal, but incomplete without the body.
• Both stress resurrection as the definitive restoration of the human person.
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Let us also also trace how this Aquinas–Catechism line contrasts with more dualistic views (Platonist or Cartesian), which the Church explicitly rejects. Here’s the contrast line by line.
1. Platonism
Plato sees the body as a prison, the soul’s true home being the world of ideas. Death is liberation. In that view, resurrection makes little sense—why would the soul want to return to the body? The Church explicitly rejects this. The Catechism says: “The Christian faith… believes in the resurrection of the body. The separation of soul and body is the state of death, but this will be definitively overcome at the end of time” (CCC 990–1014). Thomas stands firmly against Plato here: the body is not a prison but part of the human person.
2. Cartesian dualism
Descartes (17th century) radicalised the split: the soul is a thinking substance (res cogitans), the body an extended substance (res extensa), linked in a kind of awkward partnership. This led to treating the soul as the “real self” and the body as almost accidental. Catholic tradition resists that reduction. Aquinas, with Aristotle, insists that soul and body together are one substance.
3. Catholic position
The Church keeps Aquinas’s balance:
• Against Platonism, it insists the body is not disposable but part of human dignity (CCC 364–365).
• Against Cartesian dualism, it refuses to identify the “I” simply with the soul; the human person is a unity.
• The soul alone can subsist (to account for immortality), but it is in an incomplete, provisional condition until resurrection.
So where Plato says “salvation = escape from the body” and Descartes says “soul = me, body = machine,” Thomas and the Catechism say: “I am this body–soul unity. My soul can live without the body for a time, but my wholeness awaits resurrection.”
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Here are some clear places where the Church itself pushes back against Platonic or Cartesian tendencies, usually without naming them directly but making the contrast obvious:
1. Fourth Lateran Council (1215)
Canon 1 states that man is “composed of both spirit and body” (tam spiritu quam corpore). This was already a stand against the dualistic tendencies of the Cathars, who despised the body. DS 800.
2. Council of Vienne (1312)
Condemned the claim that “the rational soul is not the true form of the human body.” This was a rejection of certain neo-Platonic readings. The Council affirms Aquinas’s line that the soul is the body’s form (DS 902).
3. Fifth Lateran Council (1513)
Declared against those denying the immortality of the soul: “The soul is not only truly and essentially the form of the human body, but also immortal.” (DS 1440). This affirms both the Aristotelian–Thomistic unity and the Platonic insight of immortality, but in a balanced way.
4. Vatican II, Gaudium et Spes (1965)
Paragraph 14: “Though made of body and soul, man is one. Through his bodily composition he gathers to himself the elements of the material world… Rightly, therefore, he regards his body as good and honourable since God has created it and will raise it up on the last day.” This is a clear rejection of Platonic or Cartesian suspicion toward the body.
5. Catechism of the Catholic Church (1992)
Paragraph 365: “The unity of soul and body is so profound that one has to consider the soul to be the form of the body… Spirit and matter, in man, are not two natures united, but rather their union forms a single nature.”That’s a near-direct correction of Descartes’ dual-substance split.
So, taken together:
• Lateran IV → man is both body and spirit.
• Vienne → the soul is the form of the body.
• Lateran V → affirms immortality and form together.
• Vatican II & the Catechism → reaffirm Aquinas’s hylomorphic unity, explicitly saying body and soul form one nature.
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John Paul II leans heavily on Aquinas, but he stretches the implications in a very personalist way.
1. The body reveals the person
In his Wednesday audiences (1979–1984), collected as Theology of the Body, he insists: “The body, in fact, and only the body, is capable of making visible what is invisible: the spiritual and the divine. It was created to transfer into the visible reality of the world the mystery hidden in God from eternity.” (TOB, 19:4). Here he pushes past both Platonism (body as prison) and Cartesianism (body as machine). Instead, the body is the sacrament of the person.
2. Resurrection as fulfilment of the person
He stresses with Aquinas that the soul’s survival after death is real, but incomplete: “Eschatological man will find again in the resurrection of the body the full and definitive meaning of what it was to be human” (TOB, 66:6). That’s Aquinas’s line that beatitude is imperfect until body and soul are reunited (ST Suppl. q. 92, a. 1).
3. Unity of body and soul in imaging God
John Paul II echoes Gaudium et Spes 14: “Man is a unity. Through his body he belongs to the visible world; through his soul he penetrates into the invisible world. In both, through his very body and through his soul, he is destined for eternity” (TOB, 59:3).
4. The body as gift and vocation
For him, the body isn’t just the “matter” of the soul. It’s the place where the call to love is lived out. He speaks of the “nuptial meaning of the body”—the body shows we are made for communion, both human and divine. Resurrection then becomes the final confirmation of this vocation.
So where Aquinas supplies the metaphysics (soul = form of body, resurrection perfects beatitude), John Paul II supplies the existential weight: the body is not only essential to “me,” but also the medium through which I image God, love others, and ultimately share in divine life.
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The Catechism does not cite the Theology of the Body by name, but several passages are shaped by John Paul II’s teaching, and he himself oversaw its drafting. You can hear his voice in places where Thomistic anthropology is filled out with his personalist emphasis on the body:
1. Body reveals the person
CCC 364: “The human body shares in the dignity of ‘the image of God’: it is a human body precisely because it is animated by the spiritual soul… the whole human person is intended to become, in the body of Christ, a temple of the Spirit.” This develops Aquinas’s hylomorphism, but the language of dignity and temple echoes John Paul II’s theology of the body as a visible sign of the invisible.
2. Unity of body and soul as one nature
CCC 365: “Spirit and matter, in man, are not two natures united, but rather their union forms a single nature. That’s Aquinas against Descartes, but the wording matches John Paul II’s insistence on integral unity in his Wednesday audiences (e.g. TOB 59:3).
3. Resurrection and fulfilment
CCC 1017: “We believe in the true resurrection of this flesh that we now possess. We sow a corruptible body in the tomb, but he raises up an incorruptible body, a ‘spiritual body’ (cf. 1 Cor 15:42–44).” The “spiritual body” phrase was central to John Paul II’s catecheses on eschatological man (TOB 66–72).
4. The body as vocation to love
CCC 2331: “God is love and in himself he lives a mystery of personal loving communion. Creating the human race in his own image… God inscribed in the humanity of man and woman the vocation, and thus the capacity and responsibility, of love and communion.” This paragraph draws directly from John Paul II’s nuptial anthropology—the “nuptial meaning of the body.”
5. Marriage and the body
CCC 2363: “The spouses’ union achieves the twofold end of marriage: the good of the spouses themselves and the transmission of life. These two meanings cannot be separated without altering the couple’s spiritual life and compromising the goods of marriage.”
This is the Catechism codifying the theology of the body’s integration of unitive and procreative meanings of the conjugal act.
So: Aquinas provides the metaphysical grammar (soul = form of body, unity of person, resurrection as fulfilment), while John Paul II supplies the personalist and theological-poetic layer (the body as sacrament, as vocation to love). The Catechism weaves both strands together.
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Here’s how the line carries on after John Paul II, each pope taking the Thomist foundation but giving it a new accent.
Benedict XVI – reason, creation, destiny
• In Spe Salvi (2007), he returns to Aquinas’s insight that the soul survives death but is incomplete:
“We must think… not of the soul in abstract, but of the human person, body and soul in their unity. Only thus is creation complete. Only thus is the destiny of man fulfilled” (SS 4).
• He links resurrection to the intelligibility of creation: if God has given form to matter, he will not abandon it. Resurrection is not just an add-on, but the completion of God’s creative logic.
• Benedict uses Thomas’s metaphysics against modern reductionism—both materialism (man as only body) and spiritualism (man as only soul).
Francis – embodiment, vulnerability, ecology
• In Laudato Si’ (2015), Francis extends the Thomist body-soul unity to an ecological horizon:
“The acceptance of our bodies as God’s gift is vital for welcoming and accepting the entire world as a gift from the Father” (LS 155).
• He warns against dualisms that despise the body or treat it as raw material to be manipulated—very Cartesian in flavour.
• In Amoris Laetitia (2016), he picks up John Paul II’s personalist thread:
“The body of each spouse is not an object but is the language of their communion” (AL 151).
• Francis stresses vulnerability: the body is not only sacrament of communion, but also of fragility. He wants embodiment to remind us of limits and interdependence.
Together:
• Aquinas: metaphysical unity (soul = form of body).
• John Paul II: personalist meaning (body as sacrament of the person, vocation to love).
• Benedict: rational and cosmic depth (resurrection as the completion of creation’s logic).
• Francis: existential and ecological weight (body as gift, fragility, connectedness).
So the tradition runs like a chord: one metaphysical note, one personalist note, one rational-cosmic note, one ecological-existential note.
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Here’s how the Catechism brings all these strands together into a coherent eschatology:
1. Death and separation of soul and body
• CCC 1005: “Death is the end of earthly life. The separation of soul and body is the state of death.”
• This echoes Aquinas: the soul survives, but human wholeness is incomplete.
2. Particular judgment
• CCC 1022: “Each man receives his eternal retribution in his immortal soul at the very moment of his death, in a particular judgment that refers his life to Christ: either entrance into the blessedness of heaven—through a purification or immediately—or immediate and everlasting damnation.”
• Reflects Thomistic “particular judgment” and John Paul II’s emphasis on personal responsibility and vocation.
3. Beatific vision
• CCC 1023–1024: The souls of the just may see God immediately after death; this is true happiness, though not the full consummation.
• Aligns with Aquinas: the soul’s intellect and will can be satisfied apart from the body, but full human wholeness is lacking.
4. Resurrection of the body
• CCC 990, 1017–1018: “We believe in the true resurrection of this flesh that we now possess… We shall all rise with our bodies in Christ.”
• This restores Aquinas’s hylomorphic unity; John Paul II’s “eschatological man” is fully realised; Benedict XVI’s creation logic is respected.
5. Final judgment and new creation
• CCC 1038–1042: At the end of time, Christ will come to judge the living and the dead; the righteous will enter eternal life with glorified bodies.
• CCC 1040: “Then the righteous will shine with the glory of Christ, the new creation of both heaven and earth will be fulfilled.”
• This reflects Francis’ ecological and cosmic vision: the resurrection is not only personal but restores creation itself.
6. Summary of integration
• Aquinas: soul-body unity, resurrection as completion of human nature.
• John Paul II: body as sacrament of person, vocation to love.
• Benedict XVI: resurrection as fulfilment of creation, reason and order.
• Francis: resurrection and new creation encompass vulnerability, embodiment, and care for the cosmos.
In the Catechism, all four threads converge: human destiny is fulfilled only when body and soul are reunited in glory, fully integrated into the new creation.