79. The Unity of the Soul and Spirit versus Soul in Scripture

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Lecture Notes

Main Topics #

• Unity of the Soul vs. Platonic Dualism: Thomas defends the doctrine that man has one soul, not multiple distinct souls (vegetative, sensitive, rational). The error of positing two souls was condemned by the Eighth Council of Constantinople.
• The Hierarchy of Forms and Powers: The rational soul contains within itself all the powers of lower souls (sensitive and vegetative) just as the number five contains four, three, and two. Higher forms contain and perfect the operations of lower forms without requiring distinct substantial forms.
• Spirit and Soul as One Reality Understood Differently: In Scripture, πνεῦμα (pneuma/spirit) and ψυχή (psyche/soul) do not refer to two different entities but to the same soul considered from different aspects—soul as animating the body versus soul as possessing immaterial powers.
• The Three Aspects of Sinning: Following St. Paul, sin involves three elements that run together: reason (ratio), sensuality (sensualitas/passions), and bodily execution (executio corporis). This illuminates why Paul distinguishes these in his prayer for sanctification.

Key Arguments #

Against the Heresy of Two Souls #

• Textual Basis in 1 Thessalonians 5:23: Paul’s prayer “May the God of peace himself sanctify you wholly (ὁλοτέλης/holoteles), and may your spirit (πνεῦμα) and soul (ψυχή) and body (σῶμα) be kept blameless” does not establish two souls but rather distinguishes aspects of the unified soul in relation to sinning.
• Thomas’s Response to the Error: Those who misinterpreted Paul as teaching two souls are “disproved” (reprobata). The distinction between πνεῦμα and ψυχή is one of power (secundum potentium), not of substance (secundum essentiam).
• The Nature of Pneuma in the Soul: The powers of the soul that are acts not of bodily organs—namely reason and will—are called “spiritual” (spirituals) or immaterial. These are sometimes also called mens (mind). The same unified soul, insofar as it animates a body, is called “soul.” Insofar as it possesses immaterial powers akin to the angels, it is called “spirit.”

Understanding the Magnificat (Luke 1:46-47) #

• The Two Clauses: “My soul magnifies the Lord” and “My spirit rejoices in God, my Savior” employ the same distinction:
  • Soul (ψυχή): Understood as animating the body; refers to Mary’s bodily cooperation in the Incarnation through her flesh, blood, and milk.
  • Spirit (πνεῦμα): Understood as the immaterial aspect capable of knowing God in himself and rejoicing in Him.
• The Magnificat as Twofold Cooperation: Mary magnifies God as maker (Κύριος/Kyrios strictly means “Lord” because God made us and we belong to Him) through her bodily cooperation in the greatest work God made—the Word made flesh. She rejoices in God in himself through her spiritual powers (reason and will) illuminated by grace.
• Grace and the Spirit: The angel’s greeting, “Hail Mary, full of grace,” refers more properly to Mary’s pneuma (spirit) than her psyche (soul) because grace resides in those powers of the soul that transcend the body—reason and will. Theological virtues (faith, hope, charity) exist in reason and will, not in the senses.
• Augustine’s Principle: Mary “would profit nothing from conceiving Christ in her body if she had not first conceived him in her soul, in her spirit.”

The Gethsemane Passage (Matthew 26:41, Mark 14:38) #

• The Spiritual-Sensual Conflict: “The spirit is willing, but the flesh is weak” contrasts the immaterial power (πνεῦμα/spirit—reason and will) with the passions and emotions (which belong to the soul insofar as it animates the body). This is not a conflict between two substances but between different powers within the unified soul.
• Self-Division in Temptation: When emotions control us, “we are not in control of ourselves.” When reason is in control, we are in control. This shows that the rational power is more fundamentally us than our bodily appetites and emotions.

Worship in Spirit and Truth (John 4:24) #

• The Immateriality of True Worship: Christ teaches that authentic worship must be “in spirit and in truth” (ἐν πνεύματι καὶ ἀληθείᾳ). Since God is πνεῦμα (spirit/immaterial substance), worship acceptable to Him must engage the immaterial powers of the soul—the powers that transcend bodily organs.
• The Analogy to Angels and God: Just as angels and God Himself are called “spirits” (πνεύματα) because they are immaterial substances, so the human soul insofar as it possesses immaterial powers (understanding and will) is also called “spirit.”

Important Definitions #

Pneuma (πνεῦμα) #

• Originally means breath or air
• Extended metaphorically to name any immaterial substance (angels, God, the immaterial powers of the human soul)
• In the context of the human soul, refers to the aspect of the soul that possesses powers not dependent on bodily organs—reason (λόγος) and will
• Sometimes equivalent to mens (mind) in Latin terminology

Psyche (ψυχή) #

• The soul as such
• Emphasizes the soul’s role as the form and animator of the body
• In the context of Scripture, often highlights the soul’s connection to bodily life and bodily functions
• The same reality as pneuma when considered from the perspective of embodiment

Sensualitas (sensuality) #

• Not mere sensation but the passions and emotions of the sensitive appetite
• A power that is intrinsically bound to bodily organs
• Distinct from reason but not entirely separate—both belong to the unified soul

Ratio (reason) #

• The immaterial power of the soul for understanding and willing
• Not dependent on bodily organs for its operations
• The perfection and form-giving principle of the sensitive and vegetative powers

Examples & Illustrations #

• Aristotle’s Sleep Experiment: The story of Aristotle holding a brass ball above a basin to prevent falling asleep illustrates the intensity of his intellectual engagement and shows how powerful the rational operation can be in the human soul.
• Shakespeare’s Critique of Mere Living (Hamlet): “What is a man, if his chief good and market of his time be but to sleep and feed? A beast no more.” This poetically captures the Aristotelian principle that man without reason is not truly a man but merely an animal—demonstrating that the rational power fundamentally constitutes what we are.
• Paraphrased Version: “What is a three if it be half a four? Two and no more.” Berquist uses this adaptation to show that if man’s highest good is no more than a beast’s highest good, he becomes less than a beast (for the beast achieves its full potential, while the man fails to achieve his).
• Numeric Hierarchy: Adding unity to unity generates the next number (1→2→3→4). Similarly, adding vegetative life to matter yields a plant; adding sensation to vegetation yields an animal; adding reason to animal sensation yields man. Remove reason from man, and he is merely an animal; remove sensation, and he is merely a plant.
• Geometric Analogy: The pentagon contains the quadrilateral and exceeds it; the quadrilateral contains the triangle and exceeds it. The higher form includes the lower but adds something more. Similarly, the understanding soul contains the sensitive and vegetative operations but transcends them with rational operations.
• Premeditated vs. Passionate Murder: We judge premeditated murder more severely than murder of passion because reason is more fundamentally us than emotion. When premeditation is involved, I more fully controlled my action through my rational will.
• Loss of Consciousness: When a person loses the use of reason and sensation before death, we say they have become “vegetable.” This common usage acknowledges that the loss of these powers represents a loss of what makes one fully human.
• Self-Control and Alcoholics Anonymous: A man in Alcoholics Anonymous is true to himself when faithful to his rational choice to abstain from drinking, not when he succumbs to bodily craving. This shows that the rational choice—which belongs to the immaterial power of the soul—is more constitutive of the self than bodily appetite.
• Nurses in the Hospital: When a patient dies, nurses say “he’s gone” or “she’s gone” while the body remains. This spontaneous language reveals an implicit recognition that the departed soul is more fundamentally the person than the corpse left behind.

Notable Quotes #

“My soul magnifies the Lord, and my spirit rejoices in God, my Savior.” (Luke 1:46-47)

“The spirit is willing, but the flesh is weak.” (Matthew 26:41)

“God is spirit, and those who worship him must worship in spirit and in truth.” (John 4:24)

“What is a man, if his chief good and market of his time be but to sleep and feed? A beast no more.” (Shakespeare, Hamlet)

“These do not differ, according to their substance or nature, but according to their power.” (Thomas Aquinas, summarized by Berquist)

“He’s gone when the soul is left.” (Berquist, reflecting the Church’s understanding of death)

“I wasn’t myself today. I lost control of myself.” (Common expression showing reason is more us than emotion)

Questions Addressed #

Q: Does St. Paul teach that man has two souls—a spirit and a soul? #

A: No. Paul uses these terms to distinguish aspects or perspectives on the unified soul, not two distinct substances. The distinction is according to power (potentia), not according to essence (essentia). Some powers of the soul (reason and will) are immaterial and are called “spirit”; the same soul, insofar as it animates and gives life to the body, is called “soul.” This distinction was misinterpreted by certain ancient heretics who were condemned for positing two souls.

Q: How can the soul be both material (as animator of the body) and immaterial (as possessing reason and will)? #

A: The unified human soul is not itself material or immaterial in the way a substance is; rather, it has powers of both kinds. Some of its powers—sensation, appetite, life-giving—are acts of bodily organs. Other powers—understanding and will—transcend bodily organs in their operation. The soul is one reality with diverse powers reflecting both its role as form of the body and its participation in immaterial being.

Q: Why does Mary use different words—“soul” and “spirit”—if they are the same thing? #

A: The distinction reflects different aspects of Mary’s cooperation with God. As “soul” (ψυχή), Mary emphasizes her bodily cooperation: she provides the flesh, blood, and milk for Christ. As “spirit” (πνεῦμα), she emphasizes her immaterial cooperation: her intellect assents to God’s will, and her will rejoices in God in Himself. This two-fold cooperation is the pattern St. Augustine identifies: “Mary would profit nothing from conceiving Christ in her body if she had not first conceived him in her soul, in her spirit.”

Q: How should we understand the three things that “run together” in sin according to Thomas’s reading of St. Paul? #

A: The three elements are ratio (reason), sensualitas (the passions and emotions), and executio corporis (the body’s action). Every sin involves at least reason being corrupted (for “everyone who is bad is ignorant”). Paul prays that none of these three be corrupted: that reason remain whole and uncorrupted (preserved integer), that the sensible appetites be free from vice, and that the body not be used as an instrument of sin. This is why Paul properly distinguishes “spirit” (the immaterial power of reason) from the “soul” (the powers bound to the body) from the “body” (the material instrument).