Divine Simplicity: What It Is and Four Objections Answered

Divine simplicity is the doctrine that God has no parts of any kind, and that His essence is identical with His existence. It rules out physical parts, and it also rules out the metaphysical compositions that creatures have, such as substance with attribute, essence with existence, and act with potency. The doctrine belongs to the classical theism of Augustine, Anselm, Aquinas and Maimonides, and today it is under live attack on four fronts. Each is stated below at full strength and answered in turn, with a pointer to the fuller treatment where one exists.

Key takeaways

• Divine simplicity means God has no parts of any kind. He is His own nature and His own existence, and each of His perfections is identical with Him.
• The doctrine protects God's independence. A composite depends on its parts, and the God who exists of Himself depends on nothing.
• Four objection families stand against divine simplicity: modal collapse, the Cantorian argument against omniscience, the many attributes, and the charge of parts.
• Each objection takes a category built for creatures and applies it to God in the sense it has for us.
• Where Alvin Plantinga and R. T. Mullins conclude that simplicity must go, Frame-Indexed Classical Theism (FICT) indexes the category instead, and the objections then show only that God is not a creature.

What is divine simplicity?

The doctrine is the teaching that God is not composed of parts in any sense. He is His own nature and His own existence, and each of His perfections is identical with Him, so that there is nothing in God that is not God. The standard summary puts it as a single, unified entity with no distinction between His attributes in God Himself.

The tradition counts several ways a thing can be composed, and it denies each of them of God. A body has parts outside parts. A material thing is matter informed by form. A substance bears accidents it could lose.

In a creature, what it is and that it is are two things, since its essence does not explain its existence. And whatever can change is a mixture of act and potency, of what it is and what it could become.

The denial about essence and existence carries the most weight. Maimonides wrote that in God, "whose existence is not due to any cause … existence and essence are perfectly identical" (as quoted in the Stanford Encyclopedia of Philosophy). Aquinas gave the same claim its most famous name: God is ipsum esse subsistens, subsistent being itself, and the formula sits at the centre of Thomism.

Augustine's version is shorter still. God is what He has, he wrote in The City of God (XI, 10), as the Stanford entry reports it. A scholar has learning he might have lacked; God does not have wisdom in that way.

Simplicity is not vagueness. It does not say that God is blank or featureless, and it does not deny that we know Him truly under many names, as just and merciful and wise. It denies only that those names pick out components which together make God up.

The position behind this answer is stated in one place; read the statement.

Is God simple? Where Scripture and the church teach it

Yes, on the classical reading of Scripture, and the church has confessed as much in council and creed. The word is not in the Bible. The doctrine is an inference from two things the Bible does say: that God is one, and that He needs nothing.

The first is the Shema: "Hear, O Israel: The LORD our God, the LORD is one" (Deuteronomy 6:4, NIV). The second is Paul at the Areopagus, speaking to a city that housed and fed its gods:

"The God who made the world and everything in it is the Lord of heaven and earth and does not live in temples built by human hands. And he is not served by human hands, as if he needed anything. Rather, he himself gives everyone life and breath and everything else." (Acts 17:24–25, NIV)

A God who needs nothing cannot be assembled from anything, because an assembled thing needs its pieces. The texts do not argue for simplicity in philosophical vocabulary, and they are not proof-texts for it. They state the oneness and the non-dependence that the doctrine puts into formal terms, and the doctrine sits comfortably with both.

The church drew the inference in its own documents. The Fourth Lateran Council, in 1215, confessed the three persons as "one absolutely simple essence, substance or nature." The First Vatican Council, in Dei Filius, confessed God as "one, sole, absolutely simple and immutable spiritual substance." The Westminster Confession (2.1) says that God is "without body, parts, or passions." Because Scripture does not use the word, the objections to the simplicity of God are philosophical rather than exegetical, and they are met on that ground below.

Shorter pieces on neighbouring questions are gathered in the essays.

Why does divine simplicity matter?

Simplicity matters because it follows from God's aseity and in turn secures His immutability. A being that exists of itself can have no parts, and a God without parts has nothing to gain or lose.

The link to aseity is Aquinas's dependence argument. "Every composite is posterior to its component parts, and is dependent on them; but God is the first being" (Summa Theologiae I, q. 3, a. 7). A composite owes its being to its parts and to whatever unites them. The being that exists of itself, the subject of aseity, therefore has no parts.

Immutability follows the same line. A composite God could gain or lose parts, and a God who could gain or lose could change. Simplicity and immutability stand or fall together, and a critic who surrenders the first to save something else will find, a step later, that he has surrendered the second too.

One point of scope belongs here. The opening argument of the Many Beings series, that the natures of God and man differ in kind, rests on God's aseity set against the creature's contingency. Where it touches simplicity it needs only that God be immaterial, and it takes no stance on strict simplicity. Volume Four then argues for strong simplicity as a conclusion, not as one of the premises.

The argument from first premises to doctrine runs through Volume Four.

What are the main objections to divine simplicity?

The divine simplicity objections in current debate fall into four families, and each has its own section below.

1. Modal collapse. Stated by R. T. Mullins: a simple God had to create this world.
2. Omniscience and Cantor. Patrick Grim argues that there is no set of all truths, and so no knower of all truths.
3. The many attributes. Alvin Plantinga argues that a simple God would be a property, and Mullins that His justice would be His mercy.
4. Parts and composition. FICT's own notation seems to assemble God from qualities.

The four look unrelated, since they come from logic, set theory, metaphysics and FICT's own pages. They share a move rather than a premise, and the move is easier to see once each has been answered on its own terms.

If God is simple, did He have to create? (The modal collapse argument)

No. The modal collapse argument reaches its conclusion by putting a description of God's act in place of the act itself, and that substitution is invalid.

Mullins states it at full strength in "Simply Impossible: A Case Against Divine Simplicity" (Journal of Reformed Theology, 2013) and in The End of the Timeless God (Oxford, 2016).

God exists necessarily. On simplicity, God is identical with His one act. So that act is necessary. That act is the creating of this world. So this world exists necessarily, and neither God nor any creature could have done otherwise. The Stanford Encyclopedia states the conclusion without softening: the universe would exist "of absolute metaphysical necessity just as God does."

The reply does not touch the identity. On simplicity, God is His act, and nothing is gained by hedging that premise. The step that fails is the last: the move from "the act is necessary" and "the act is the creating of this world" to "this world is necessary."

Necessity attaches to the act itself, taken in itself. "The act of creating this world" picks out that one act by way of its creature-side effect, and descriptions of that kind do not carry necessity through modal contexts. Christopher Tomaszewski showed that the inference is invalid ("Collapsing the Modal Collapse Argument," Analysis 79, 2019: 275–84). From the premises it follows that the act is necessary. It does not follow that the act-as-creating-this-world is.

The relation behind that description runs one way. Creatures change in relation to God, and God does not change in relation to them. The modal version is one step further: across possible worlds, what varies is the world, and God does not vary with it. The difference between God-creating-this-world and God-creating-another lies in the created term.

Mullins presses a further question, and it is a fair one. What distinguishes the eternity in which God creates from the eternity in which He does not? Nothing in God, and that is the doctrine of free creation, not an embarrassment to it.

The difference lies wholly in the created term of an asymmetric relation: God grounds the world and is grounded by nothing. To demand an intrinsic divine difference for each creaturely difference is to demand that God vary with His world. Paul's doxology runs in one direction: "For from him and through him and for him are all things. To him be the glory forever! Amen." (Romans 11:36, NIV)

That is the answer in outline. The modal collapse argument has its own page, where each step is worked through.

Volume One sets out the position from its foundations, and it is free on Kindle.

Can a simple God know every truth? (Omniscience and Cantor's theorem)

Yes. Patrick Grim's argument proves that there is no set of all truths, and omniscience is not a set.

Stated at full strength, the argument runs like this. Suppose God knows all truths, and consider the set of them. By Cantor's theorem, the subsets of any set of truths generate further truths beyond it, as the power set of a set outruns the set.

So there is no set of all truths, and Grim concludes that there can be no knower of all truths either. The debate's standing form is his exchange with Alvin Plantinga, "Truth, Omniscience, and Cantorian Arguments: An Exchange" (Philosophical Studies 71, 1993).

The reply concedes the mathematics entire. The premise that fails is the one that treats God's knowledge as an inventory of discrete propositional items, a totality that would have to be gathered for Him to know it. On the classical doctrine, God's knowledge is one simple act: His knowing of Himself and of all He wills and sustains.

Distributively means taken one at a time; collectively means gathered into a single completed whole. Taken distributively, nothing is lost. For any truth you name, God knows it. What never existed is the completed collective object, and omniscience did not need one.

William Alston reached a neighbouring conclusion by another road in "Does God Have Beliefs?" (Religious Studies 22, 1986), arguing that God's knowledge need not involve belief. His is a neighbouring view.

Scripture's own wording fits the reply: "Great is our Lord and mighty in power; his understanding has no limit" (Psalm 147:5, NIV). The Hebrew says His understanding is beyond number, and a knowledge without a count is not a set that lacks one.

This answers the set-of-all-truths form of Grim's argument, and it claims no more than that. The full treatment of Cantor and omniscience takes the argument further, and the separate question of God's foreknowledge has its own page.

Volume Five works through the mathematics of infinity chapter by chapter; follow its progress.

If God is His attributes, is God a property?

No. The objection assumes that God must fill one of the two slots creaturely metaphysics offers, a bearer of properties or a property, and He is neither.

Alvin Plantinga gave the objection its classic form in Does God Have a Nature? (1980). If God is identical with each of His properties, then each property is identical with each of the others, and God has but one property. That, in Plantinga's words, "seems flatly incompatible with the obvious fact that God has several properties" (as quoted in the Internet Encyclopedia of Philosophy). Worse, God would then be a property, and properties are abstract and causally inert.

Mullins sharpens the second edge. Writing for the Theopolis Institute in 2019, he states the doctrine's claim as "God's property of omniscience is identical to God's omnipotence, and these in turn are identical to God's existence." If that holds, justice is mercy, and the two words stop telling us anything.

The word carrying the objection is "property," and it is used univocally, in the sense it has for creatures. For creatures the apparatus of properties and bearers is correct. A creature gains a quality, loses it, has it by degrees, and shares it with other creatures.

Applied to God, the same apparatus forces a taxonomy built for composite, participating things onto the one being who is neither composite nor a participant. God is pure act, actus purus. He is not an inert abstraction but the one act of knowing, willing and loving in which His whole life is possessed. An abstract object is inert, and pure act is the living source on which creaturely causes depend. God is a personal God without residue.

Justice and mercy do not become synonyms either. Scripture proclaims God under distinct perfections in a single breath: "The LORD, the LORD, the compassionate and gracious God, slow to anger, abounding in love and faithfulness … Yet he does not leave the guilty unpunished" (Exodus 34:6–7, NIV). God is truly known under each of these, and the concepts stay distinct while the God they name is one.

A neighbouring view on this point is the truthmaker defence of Jeffrey Brower and Michael Bergmann, on which God Himself is the truthmaker for essential predications such as "God is omniscient," rather than an exemplifier of a property or identical to one (Stanford Encyclopedia, section 5).

The chapter behind this section, with its full argument, is in Volume Four.

Does God have parts? Composition and the position's own notation

No. Composition is how a finite mind takes in what it cannot hold whole, and it is not an inventory of God. The positive reason is Aquinas's dependence argument, already given: a composite depends on its parts, and God depends on nothing.

The sharpest form of this family is aimed at the position defended here. Its formal notation writes a being's nature as the fusion of its essential qualities. Applied to God, does that not assemble Him from parts on the position's own first page? The objection is fair, and a position that polices other people's categories has to answer it about its own.

The answer is that the notation records how the simple God is truly known by minds that cannot receive Him except as many perfections. It does not compose Him. What a finite formalism has to write as many qualities held in unity, God is as one act.

A formalism written in the creature's mode is still true knowledge in that mode, and being notated from the knower's side does not make it false. Reformed theology, following Franciscus Junius, has a name for knowledge of this kind: ectypal theology, the creature's knowledge fashioned from the archetypal knowledge God has of Himself, and the position defended here adopts that distinction.

The position's terms are defined on a single page.

What do the four objections have in common?

Each takes a category native to creatures and predicates it of God in the same sense it has for us.

Frame-Indexed Classical Theism is a research program in analytic theology that resolves classical theological dilemmas by diagnosing them as artifacts of a single formal error, and it is the position the Many Beings series argues. One reality is known in two incommensurable ways. God knows it in a perceptual frame that is atemporal, simple and a se; we know it in a frame that is sequential, composite and contingent. God's frame is the ground of ours: it contains and sustains the finite frame, not the reverse.

Predicates whose content involves time, modality, agency or value are said of God and of us analogically and not univocally, and treating such a term as though it meant the same on both sides is the error FICT calls the Many Beings Fallacy.

Where Plantinga, Mullins and Craig give up the doctrine of divine simplicity to keep the objection's category, and where the truthmaker defence of Brower and Bergmann answers each objection piecemeal, Frame-Indexed Classical Theism indexes the category. The rivals see something true.

Plantinga and Mullins are right that a God who was a property could not be the God of Scripture. Brower and Bergmann are right that the property apparatus cannot be applied to God in the sense it has for creatures. FICT keeps both points and names the move that produced the objections.

Plantinga's argument makes God a property. Grim's makes His knowledge a set. The composition charge treats His perfections as parts. And in the modal collapse argument, a description of God's act by its effect is allowed to stand in for the act.

At the root lies a difference in being between Creator and creature, which shows up in how words cross from one to the other. Duns Scotus held that being is said univocally of both, and FICT rejects that thesis at its foundation. Apophatic theology approaches God by negation, speaking of what He is not. FICT holds, with Aquinas, that positive predication is true and analogical, and it formalizes the rule that governs it.

The position has a price, which is analogical discipline at each step, and it can be tested. Show a term whose content involves time, modality, agency or value crossing the two frames univocally where the diagnosis says it cannot, and the diagnosis fails.

Volume One argues all of this from the ground up, and your copy is free.

How do the positions on simplicity compare?

Each position protects something real, and each pays for it somewhere.

Frequently asked questions

Is divine simplicity biblical?

The word is not in Scripture, but the doctrine sits comfortably with what Scripture says: that the LORD is one (Deuteronomy 6:4), and that God is not served "as if he needed anything" (Acts 17:25). A God who needs nothing cannot depend on parts. The church drew that inference in its councils and confessions.

What are the main problems with divine simplicity?

Those most often raised fall into four families: modal collapse, the Cantorian argument against omniscience, the charge that God would be a property, and the charge that the doctrine hides parts. Each takes a category built for creatures and applies it to God in the sense it has for us.

Does divine simplicity mean God had to create the world?

No. The argument substitutes a description of God's act, named by its effect, for the act itself, and necessity does not pass through that substitution. The page on the modal collapse argument takes it step by step.

Does the Trinity contradict divine simplicity?

The tradition's answer is that the three persons are distinguished by relations of origin, not by a division of the essence. Augustine taught that the persons differ according to relation and not according to substance (De Trinitate V), and Aquinas that each person is the one essence under a relation of origin (Summa Theologiae I, q. 29, a. 4). The position defended here has no doctrine of the Trinity and derives none; it receives the doctrine from Scripture and the councils.

Is divine simplicity the same as aseity?

No. Aseity concerns dependence and simplicity concerns composition. Aquinas argued that the first entails the second, since a composite depends on its parts, and aseity has its own full treatment.

Where to go from here

Each objection in this piece proves something true about a creature. Properties are inert, a set of all truths cannot exist, and parts come before their whole. Each of those claims is true. Each is about the wrong object. The pages on the modal collapse argument and on Cantor and omniscience take the two sharpest objections further, Volume Four carries the simplicity chapter, and Volume Five carries the mathematics.

Volume One starts at the beginning, and it is yours free.