Divine simplicity: Sources and their use

Divine SimplicitySource, Freedom, and Communion

Reading the sources

The project distinguishes Scripture, Catholic doctrinal teaching, primary philosophical arguments, and its own constructive synthesis. These sources are consulted for particular claims. A reference does not imply that its author states or endorses the entire account developed here.

Scripture

Romans 11, especially verse 36, gives the doxological language of all things from God, through God, and toward God. Its context should remain visible when that language is used philosophically.

1 Corinthians 15, especially verses 20 through 28, places God all in all within Christ's resurrection, reign, defeat of death, and handing over of the kingdom. It supplies a revealed horizon of consummation rather than a complete metaphysical demonstration or an isolated verdict about every person's salvation.

Hebrews 1 concerns the Son's divine dignity, relation to the Father, and sustaining action. Read it alongside the Church's Trinitarian confession rather than as an independent formal semantics of identity.

John 1, John 14, and John 17 illuminate the Word, the disclosure of the Father, divine indwelling, and communion. The Incarnation and its saving economy govern their theological interpretation.

2 Peter 1, especially verse 4, supplies the language of participation in divine nature. The theological account must distinguish graced participation from identity of substance.

Catholic teaching

The Catechism on speaking about God, paragraphs 39 through 43, concerns truthful language about God together with the limits of creaturely concepts.

The Catechism on the one God, especially paragraph 202, articulates the confession of one simple divine essence in three Persons.

The Catechism on the Father and Trinity, paragraphs 232 through 267, is central for real personal distinction, consubstantiality, origins, the common divine operation, and personal missions.

The Catechism on the Creator, paragraphs 279 through 324, addresses free creation, communication of goodness, sustaining causality, providence, secondary causes, and evil.

The Catechism on the Son of God becoming man, paragraphs 456 through 483, gives the Christological distinctions needed for true humanity, the union of natures in one Person, and Christ's human knowing and willing.

The Catechism on Eucharistic presence, especially paragraphs 1374 through 1377, states substantial presence, transubstantiation, and Christ's undivided presence under the sacramental species.

The Catechism on grace, paragraphs 1996 through 2002, addresses God's gratuitous gift and participation in divine life.

The Catechism on heaven, paragraphs 1023 through 1029, concerns immediate vision, communion with the Trinity, and the blessed's personal identity.

John Paul II's Fides et Ratio, especially sections 49 through 51, concerns philosophy's proper inquiry and the Church's doctrinal discernment. A Catholic philosophical account remains responsible for its arguments.

Primary philosophical arguments

Thomas Aquinas's Summa Theologiae provides especially relevant arguments in I question 2 on God's existence, I question 3 on simplicity, I question 4 on perfection, I question 11 on unity, and I question 13 on divine names.

For knowledge and freedom, consult I question 14 and I question 19. For power and creation, consult I question 25 and I question 44. These arguments are historical resources with definite premises. The project identifies where its own explanatory proposals go beyond their explicit formulations.

For divine relations and unity of essence, consult I question 28 and I question 39. For eternity and divine action through creatures, consult I question 10 and I question 105.

The constructive account

The expressions unreceived plenitude, measured manifestation, supported agency, and the All name the constructive work developed in these essays. Their value depends on the explanations they supply. A cited source can support a premise or illuminate a problem without making that source responsible for the project's entire synthesis.

The Method page explains how to distinguish doctrine, philosophical inference, conditional consequence, and contested proposal. Each article identifies a more local set of readings and the question those texts address.

Quoted primary sources

Indented passages are source quotations. The surrounding explanations and arguments are the author’s own. Translation information accompanies each passage.

the Father and the Son and the Holy Spirit; three persons indeed, but one essence, substance or nature entirely simple.

Fourth Lateran Council, Profession of faith, quoted in the Catechism of the Catholic Church, CCC 202; Fourth Lateran Council (1215)Official Vatican English text of the CatechismThe conciliar profession confesses one eternal, unchangeable, almighty God, then names the three Persons and the entirely simple divine essence. This excerpt begins within that profession.

Read in Question 01

The Church has no philosophy of her own nor does she canonize any one particular philosophy in preference to others.

Saint John Paul II, Fides et Ratio, 49Official Vatican English textThe paragraph defends philosophy's proper principles and methods while preserving the Magisterium's responsibility to discern conflict with revelation.

Read in Question 01

It repenteth me that I have made Saul king: for he hath forsaken me, and hath not executed my commandments.

Sacred Scripture, First Book of Kings (1 Samuel), 15:11Douay-Rheims (Challoner revision)The statement concerns Saul's disobedience; verse 29 in the same narrative denies humanlike repentance of God and affirms the announced judgment's firmness.

Read in Question 02

But the triumpher in Israel will not spare, and will not be moved to repentance: for he is not a man that he should repent.

Sacred Scripture, First Book of Kings (1 Samuel), 15:29Douay-Rheims (Challoner revision)Samuel declares the firmness of God's rejection of Saul as king; the wording must be interpreted alongside the chapter's own uses of divine repentance in verses 11 and 35.

Read in Question 02

If that nation against which I have spoken, shall repent of their evil, I also will repent of the evil that I have thought to do to them.

Sacred Scripture, Prophecy of Jeremias (Jeremiah), 18:8Douay-Rheims (Challoner revision)The potter passage describes conditional warnings and promises in verses 7–10 and calls Judah to conversion in verse 11; the evil threatened by God means calamity rather than moral wrongdoing.

Read in Question 02

Therefore it must be that all things which are diversified by the diverse participation of being, so as to be more or less perfect, are caused by one First Being, Who possesses being most perfectly.

Thomas Aquinas, Summa theologiae, I, q. 44, a. 1, I answer thatFathers of the English Dominican Province, Second and Revised Edition (1920), as presented by New Advent.Aquinas argues from participation to a universal source after invoking his earlier arguments for subsistent being and its uniqueness. The passage should not be presented as an inference from one observed change directly to every divine attribute.

Read in Question 03

Secondly, because every composite is posterior to its component parts, and is dependent on them; but God is the first being, as shown above (I:2:3).

Thomas Aquinas, Summa theologiae, I, q. 3, a. 7, I answer thatFathers of the English Dominican Province, Second and Revised Edition (1920), as presented by New Advent.This is one of several arguments for simplicity in this article. Its force depends on the stated priority and dependence of components and on the prior first-being argument; it is not a definition making every conceivable distinction a dependent part.

Read in Question 04

But if the Divine and unalterable nature is incapable of degeneracy, as even our foes allow, we must regard it as absolutely unlimited in its goodness: and the unlimited is the same as the infinite.

Gregory of Nyssa, Against Eunomius, Book I, section 15William Moore and Henry Austin Wilson, Nicene and Post-Nicene Fathers, Second Series, vol. 5 (1893), as presented by New Advent.Gregory opposes Eunomius's unequal ranking of Father, Son, and Spirit: unlimited divine goodness admits no greater or lesser degree. This supplies a materially different argument about divine infinitude; it does not establish every one of the six simplicity audits or erase personal distinction.

Read in Question 04

Since therefore God is subsisting being itself, nothing of the perfection of being can be wanting to Him.

Thomas Aquinas, Summa theologiae, I, q. 4, a. 2, I answer thatFathers of the English Dominican Province, Second and Revised Edition (1920), as presented by New Advent.This is the second of two arguments for divine perfection. Aquinas supplies a positive bridge from subsistent being to perfection; the article also distinguishes eminent causal possession from possessing each creaturely form in its creaturely manner.

Read in Question 05

For God is not Existent in any ordinary sense, but in a simple and undefinable manner embracing and anticipating all existence in Himself.

Pseudo-Dionysius the Areopagite, The Divine Names, Chapter V, section 4C. E. Rolt, Dionysius the Areopagite: On the Divine Names and the Mystical Theology (London: SPCK, 1920); public-domain text at CCEL.Dionysius combines causal precontainment with an apophatic account of the source beyond ordinary existence. His language of super-essential transcendence differs from Aquinas's subsistent-being analysis and should not be silently equated with it; the passage does not establish free selection among worlds.

Read in Question 05

not to increase his glory, but to show it forth and to communicate it

Bonaventure, Commentary on the Sentences, quoted in the Catechism of the Catholic Church, In II Sent. I, 2, 2, 1, as cited in CCC 293, note 135English wording quoted in the official Catechism of the Catholic Church, paragraph 293. Verified through this quotation and its source note; the original commentary was not independently retrieved.The Catechism attributes these words to Bonaventure to explain that creation manifests and communicates divine glory rather than increasing it. The same paragraph immediately quotes Vatican I on creation with absolute freedom of counsel. Communicability therefore supplies no inference here to necessary emanation or to a world needed for divine perfection.

Read in Question 05

Therefore although the names applied to God signify one thing, still because they signify that under many and different aspects, they are not synonymous.

Thomas Aquinas, Summa theologiae, I, q. 13, a. 4, I answer thatFathers of the English Dominican Province, Second and Revised Edition (1920), as presented by New Advent.Aquinas preserves differences in the meanings of divine names while arguing for one simple divine reality. His account connects our multiple conceptions with perfections received separately by creatures.

Read in Question 06

But in God to be is the same as to be strong, or to be just, or to be wise, or whatever is said of that simple multiplicity, or multifold simplicity, whereby to signify His substance.

Augustine of Hippo, On the Trinity, Book VI, chapter 4, section 6Arthur West Haddan, Nicene and Post-Nicene Fathers, First Series, vol. 3 (1887), as presented by New Advent.Augustine argues for the Son's equality with the Father in all predicates signifying divine substance, contrasting God with a human mind that can lack virtues. The passage concerns essential perfection within a Trinitarian argument, rather than making personal relations interchangeable.

Read in Question 06

Therefore all beings apart from God are not their own being, but are beings by participation.

Thomas Aquinas, Summa theologiae, I, q. 44, a. 1, I answer thatFathers of the English Dominican Province, Second and Revised Edition (1920), as presented by New Advent.Participation here concerns caused possession of being, contrasted with subsistent being. It does not mean that creatures are fragments of the divine substance or that their existence is unreal; agency and disclosure need further arguments.

Read in Question 07

But our mind cannot be led by sense so far as to see the essence of God; because the sensible effects of God do not equal the power of God as their cause.

Thomas Aquinas, Summa theologiae, I, q. 12, a. 12, I answer thatFathers of the English Dominican Province, Second and Revised Edition (1920), as presented by New Advent.The same answer allows knowledge that God exists and of what belongs to the first cause through its effects, while denying comprehension of the divine essence by sense-based reasoning. Causal evidence is bounded and is not automatically a revealed message.

Read in Question 08

Active power is not contrary to act, but is founded upon it, for everything acts according as it is actual: but passive power is contrary to act; for a thing is passive according as it is potential.

Thomas Aquinas, Summa theologiae, I, q. 25, a. 1, Reply to Objection 1Fathers of the English Dominican Province, Second and Revised Edition (1920), as presented by New Advent.Aquinas distinguishes active power from receptive potentiality. The distinction supports creative efficacy without deficiency; it does not itself explain why one possible creation is freely intended rather than another.

Read in Question 09

We must hold that the will of God is the cause of things; and that He acts by the will, and not, as some have supposed, by a necessity of His nature.

Thomas Aquinas, Summa theologiae, I, q. 19, a. 4, I answer thatFathers of the English Dominican Province, Second and Revised Edition (1920), as presented by New Advent.Aquinas offers three arguments for voluntary divine causality and distinguishes intellect, will, and executive power in the replies. This historical position must still face the question of how a definite free intention accounts for the actual world.

Read in Question 10

Although God necessarily wills His own goodness, He does not necessarily will things willed on account of His goodness; for it can exist without other things.

Thomas Aquinas, Summa theologiae, I, q. 19, a. 3, Reply to Objection 2Fathers of the English Dominican Province, Second and Revised Edition (1920), as presented by New Advent.Aquinas distinguishes willing divine goodness necessarily from willing creatures non-necessarily. The body also distinguishes absolute necessity from necessity by supposition; the quotation does not license transferring necessity from divine existence to each created effect.

Read in Question 11

As the divine essence is necessary of itself, so is the divine will and the divine knowledge; but the divine knowledge has a necessary relation to the thing known; not the divine will to the thing willed.

Thomas Aquinas, Summa theologiae, I, q. 19, a. 3, Reply to Objection 6Fathers of the English Dominican Province, Second and Revised Edition (1920), as presented by New Advent.Aquinas distinguishes the necessity of the divine essence and powers from necessity in the will-object relation. This is his historical reconciliation claim, not a demonstration that the complete intrinsic intentional profile is invariant across possible worlds.

Read in Question 12

Now it is manifest that God causes things by His intellect, since His being is His act of understanding; and hence His knowledge must be the cause of things, in so far as His will is joined to it.

Thomas Aquinas, Summa theologiae, I, q. 14, a. 8, I answer thatFathers of the English Dominican Province, Second and Revised Edition (1920), as presented by New Advent.The surrounding argument explicitly says that an intelligible form alone does not determine an effect without willing. Productive knowledge is Aquinas's account here; citing it does not independently explain actual-world knowledge or settle the harder case of free creaturely action.

Read in Question 13

We must therefore understand that God works in things in such a manner that things have their proper operation.

Thomas Aquinas, Summa theologiae, I, q. 105, a. 5, I answer thatFathers of the English Dominican Province, Second and Revised Edition (1920), as presented by New Advent.Aquinas explicitly rejects the view that created powers produce no effects. He argues that primary divine causality includes rather than replaces creatures' own operations; a further account of voluntary action is required for responsibility.

Read in Question 14

The will of God is entirely unchangeable. On this point we must consider that to change the will is one thing; to will that certain things should be changed is another.

Thomas Aquinas, Summa theologiae, I, q. 19, a. 7, I answer thatFathers of the English Dominican Province, Second and Revised Edition (1920), as presented by New Advent.Aquinas distinguishes a changing intention from an unchanged intention for ordered changes. This concerns temporal immutability, not by itself sameness of complete divine intentional content across alternative possible creations.

Read in Question 15

Because it does not divide the divine unity, the real distinction of the persons from one another resides solely in the relationships which relate them to one another:

Catholic Church, Catechism of the Catholic Church, 255Official Vatican English textThis sentence introduces the Catechism's conciliar citations on relational names, opposition of relationship, and the Persons' mutual indwelling.

Read in Question 16

The divine persons do not share the one divinity among themselves but each of them is God whole and entire:

Catholic Church, Catechism of the Catholic Church, 253Official Vatican English textThe Catechism confesses the consubstantial Trinity, then quotes conciliar texts affirming one undivided divine substance.

Read in Question 17

But it is the name of the Relation in which the Father stands to the Son, and the Son to the Father.

Saint Gregory of Nazianzus, Oration 29 (Third Theological Oration), 16Charles Gordon Browne and James Edward Swallow, Nicene and Post-Nicene Fathers, Second Series, vol. 7 (1894), as transcribed by New AdventGregory rejects the dilemma that Father must name either an essence different from the Son's or an action that makes the Son a creature; he then affirms identity of nature between begetter and begotten.

Read in Question 18

Being a work at once common and personal, the whole divine economy makes known both what is proper to the divine persons, and their one divine nature.

Catholic Church, Catechism of the Catholic Church, 259Official Vatican English textThe preceding paragraph teaches one divine operation and each Person's unique personal property; this paragraph explains communion with the Persons without separating their nature.

Read in Question 19

Mercy is especially to be attributed to God, as seen in its effect, but not as an affection of passion.

Saint Thomas Aquinas, Summa theologiae, I, q.21, a.3, corpusFathers of the English Dominican Province, second and revised edition (1920), as transcribed by New AdventAquinas distinguishes sorrow's passive affection from mercy's removal of misery and explains goodness, justice, liberality, and mercy as distinct aspects of God's bestowal of perfection.

Read in Question 20

Thus everything in Christ's human nature is to be attributed to his divine person as its proper subject, not only his miracles but also his sufferings and even his death:

Catholic Church, Catechism of the Catholic Church, 468Official Vatican English textThe paragraph receives Constantinople II's confession that Christ is one Person of the Trinity, while the following paragraphs preserve his full humanity and two natural wills.

Read in Question 21

To this question, as pressing as it is unavoidable and as painful as it is mysterious, no quick answer will suffice.

Catholic Church, Catechism of the Catholic Church, 309Official Vatican English textThe question is why evil exists if the almighty Creator cares for all creatures; the Catechism situates its answer within the whole Christian faith rather than a single explanation.

Read in Question 22

Christ is present whole and entire in each of the species and whole and entire in each of their parts, in such a way that the breaking of the bread does not divide Christ.

Catholic Church, Catechism of the Catholic Church, 1377Official Vatican English textThe preceding paragraph confesses transubstantiation, and this paragraph states the duration and undivided character of Christ's sacramental presence.

Read in Question 23

And when all things shall be subdued unto him, then the Son also himself shall be subject unto him that put all things under him, that God may be all in all.

Saint Paul, First Letter to the Corinthians, 15:28Douay-Rheims (Challoner revision)Verses 20–28 concern Christ's resurrection, his reign, the defeat of death, and the kingdom's consummation. The Son's subjection is read within the incarnate economy, without assigning him an inferior divine nature.

Read in Question 24

man will remain whole man in soul and body, owing to his nature, but will become whole God in soul and body owing to the grace and the splendor of the blessed glory of God

Maximus the Confessor, Ambigua (On Difficulties in the Church Fathers), Ambiguum 7.26; Nicholas Constas (2014), vol. 1, p. 113; quoted in Samuel Korb (2022), p. 317, note 57Nicholas Constas, On Difficulties in the Church Fathers (Harvard University Press, 2014), vol. 1, p. 113, as quoted and verified through Samuel Korb, “Whole God and whole man: Deification as incarnation in Maximus the Confessor,” Scottish Journal of Theology 75 (2022), p. 317, note 57. The Constas volume itself was not independently retrieved.Maximus juxtaposes the persistence of embodied human nature with becoming God by grace. This supports real deification without identifying created and divine natures. The wording is quoted through Korb; adopting it does not adopt the article's further disputed interpretation of deification as hypostatic identity or attribute the site's constructive metaphysical model to Maximus.

Read in Question 24

A philosophy which did not proceed in the light of reason according to its own principles and methods would serve little purpose.

Saint John Paul II, Fides et Ratio, 49Official Vatican English textThis statement explains philosophy's proper rational autonomy; the encyclical also requires attention to revealed truth and distinguishes that autonomy from exemption from doctrinal discernment.

Read in Question 25

References

The references below collect the linked texts used across the questions. Each question also provides the sources relevant to its own argument.