Christians across the ages have confessed God’s simplicity, and it also remains as a stalwart foundation for the reformed faith. The Belgic Confession (1561), for example, begins by affirming that God is “ single and simple spiritual being.” And Francis Turretin (1623–1687) remarks, “The orthodox have constantly taught that the essence of God is perfectly simple and free from all composition” (1992: 1:191).
Divine simplicity means that God has no parts or possibility. He is actually and always who he claims to be.
Yet some today reject divine simplicity as being nonbiblical and incoherent. Is it?
Objections to Divine Simplicity
Evangelical theologian John Feinberg levies a number of arguments against the doctrine. Consider the following six arguments.
Objection 1. Divine simplicity is nonbiblical: “There is no verse that explicitly teaches that God is simple (2001: 327).”
Objection 2. Biblical arguments for simplicity wrongly read metaphysics into the surface grammar of the text. Such arguments “beg the question and wrongly use surface grammar as indicating that these verses teach the doctrine.” (2001: 328)”
Objection 3. Since traditional immutability may not be true, God does not have to be simple: “if one defines immutability as I have, so that God can change his relationships, then it isn’t clear that an immutable being must also be simple” (2001: 328).
Objection 4. God is temporal and so has a before and after in him (thus, not simple in the classic sense): “I believe that the best way to understand God’s relation to time is to see God as temporal” (2001: 427).
Objection 5. divine simplicity is incoherent because it identifies God’s nature with his properties.
(a) So God only has one property, which does agree with the Christian claim that God has many properties (2001: 329–331).
(b) Second, then God must be a property, which he is not (2001: 329–331).
(c) Third, since God knows accidental things like having created Adam or knowing that the sinned, he would be identical with these accidental properties (2001: 331)
Objection 6. Trinitarian relations in God (which assume simplicity) are non-unbiblical and incoherent. “In sum, it seems wisest to abandon the doctrines of eternal generation and eternal procession. They are shrouded in obscurity as to their meaning, and biblical support for them is nowhere near as strong as supposed” (2001: 494).
Feinberg does not make this connection explicitly because he may be unaware of the connection between simplicity and trinitarian relations (eternal generation, procession, etc.). But the argument remains valid if true.
Arguments for Divine Simplicity
Before answering each objection, consider the following arguments for divine simplicity. The doctrine of divine simplicity derives from Scripture because it is a necessary consequence of biblical revelation. It also coherently stands up to the test of reason.
1. Power and act. God created all things (Gen 1) and gave life to all (Gen 2:7; Rom 11:36; Acts 17:25). God created everything that moves. He put into motion the waters, the birds, the trees, the world, the sun, the moon, and the universe, and all things. Everything in motion had a little shove to get going. God gave that shove, that push into motion.
Now, God differs from things that move as we do. Nobody gave God a shove to create. Since nothing exists before God (John 1:1), then nothing could have pushed him to act. So he has to exist in such a way that he can create without anyone needing to ask or to push him to do so.
And this mode of existence is what Christians call simplicity. It means that has no possibility or unrealized power. He simply does according to his nature. He created not because he was pushed; but because he is pure act.
In this argument for simplicity, then, we reflect on what it means for God to create. In answer, we say that God put everything into motion because he created and nothing made him do it. He just did it because he does not need to be moved to act as created things do (e.g., hunger moves us to eat).
2. Composition and spirit. A second feature of the argument includes the revealed nature of God. Jesus claims, “God is spirit” (John 4:24). Bodies have material (flesh, blood) and immaterial aspects (spirit). So they are composite. But God is spirit. Therefore, he has no bodily parts. This also represents a key insight into the doctrine of divine simplicity.
3. Essence and existence. God gives people existence: “there is one God, the Father, from whom are all things and for whom we exist, and one Lord, Jesus Christ, through whom are all things and through whom we exist” (1 Cor 8:6; cf. Acts 17:25). Now, we know about human nature or essence. So that nature is real. But before someone is born, they do not exist even though human nature does. When it comes to humans then, we can separate the idea of essence from existence.
But no person or thing precedes God to give him existence. And God alone possesses a divine essence. He is one God. So God’s nature could not and did not exist without him existing. So, both his essence (divinity) and his existence (life) coexist or are the same thing. Jesus does say, “I am the life” and not just “I live” (John 14:6). So in God, essence and existence are the same thing. God has no parts, then, in terms of essence and existence.
4. Properties and number. The Bible identifies God in a number of ways. John says, “God is light” (1 John 4:8), “God is light” (1 John 1:5), and “God is Spirit (John 4:24). God is also a “consuming fire” (Heb 12:29). God also is “a God merciful and gracious, slow to anger, and abounding in steadfast love and faithfulness” (Exod 34:6–7).
And God retains these properties always: “you are the same, and your years have no end” (Ps 102:27). With God, “there is no variation or shadow due to change” (James 1:17). A necessary consequence then is that God unchangeably holds his properties such as being light, love, and spirit. If that’s true, then he does grow to be more loving or more spirit or more light. He is these things.
And since he created and exists as the source of all things, he must be the best in class or the standard of love, light, mercy and so on. Scripture confirms this notion when it says that God “perfect in knowledge” (Job 37:16), that God’s law is perfect (Ps 19:7), and that his work is perfect (Deut 32:4).
Besides this, it is obvious that God has to be the greatest being since every good thing comes from him (Gen 1:31; Rom 11:36; James 1:17). He, therefore, must be the best of class. God’s being goes beyond our understanding (Isa 55:8–9; Rom 11:33–34). It is beyond it because it is greater than our capabilities allow us to grasp; hence, better.
So if his properties are unchangeable and the best, then they can never get worse or better. To lessen or greaten implies change. To grow would imply that God is not the best now; to worsen would mean God would lose the the characteristic of bestness. And the best thing is singular not multiple or else there would be many things called the best which is impossible. So the attributes of God reflect the singular perfection of God, his simple essence.
Additionally, if God is spirit and bodiless, then how should we conceive of him and his properties? Does he have one quadrant of love and another of mercy? Probably not. Scripture claims God is love. Not that love shares in a part of God. Love is who he is.
Further, when we try to think about an eternal spirit like God, we have to admit that we cannot directly apply temporal fleshly categories to God. We have love. We change and so exist in time. But God is love; he is changeless and so timeless. For a being like this who always acts according to nature (pure act), it would not make sense to think of him as having different parts when it comes to attributes. This would imply that he activates some properties at one time, and then others at another time. But God is not the God of the possible but the actual.
Also, if properties come together to make up God. Then it seems like properties come together into a composite thing which defines God. So God’s properties would logically precede who God is and seem to be a second thing. But God is one and nothing precedes him. So properties are identical to the essence of God. And everything in God is God. There is no second thing that is not the essence of God (a composite of properties or the various properties themselves).
He perfectly possesses all the properties in his simple nature. He is love and mercy at the same time and in a simple way. So we can identify God’s essence with his properties. He is love in a way fitting for an eternal spirit—so not how we have these things.
5. Essence and persons. The most important argument, I would say, is simplicity’s explanatory power for the central confession of Christianity: namely, that we are baptized in the name of the Father, Son and Holy Spirit.
Christians had to figure out how to worship one God while also worshipping Jesus. They confessed the Lord is one, but also more (1 Cor 8:6; Deut 6:4). Divine simplicity provided a coherent way to make sense of this twofold confession.
Since God has no physical parts, no potentiality, and may be identified with his properties, then it stands to reason that God may remain one God while having threeness. Simplicity provided the answer: God has three subsisting persons in his one nature. God is one and three without conflict.
Simplicity explains tri-unity. And without simplicity, tri-unity would not work. Hence, by the truth of the effect (tri-unity), we can discern the cause (simplicity). And this cause fits with what Scripture has said elsewhere.
6. Persons and relations. Since God is three yet one God, somehow three persons subsist in God. The fact that they do derives from the simple nature of God. But how they do so also follows from God’s simplicity.
Scripture defines God as Father and Son. So it defines a relationship of paternity and sonship. Since Scripture assumes reality (who God is), it often communicates its truth according to the truth of God. We get traces of reality but not always the full picture. Yet the Son (John 17:1) is said to exist before the world and share in God’s glory (John 17:5).
Elsewhere, the relationship between Father and Son correlates as God and Logos (John 1). In this context, the Word of God exists in God before all ages as the immaterial Logos in the mind of God.
Both analogies Father-Son and God-Logos show unity and distinction (as does the analogy of gazer and Image in Col 1:15). Unity in terms of number (one God), and distinction in terms of the relationship (e.g., Father and Son). Hence, trinitarian persons differ by means of their relationship but not in terms of their number. There is one God in whom is one Father, one Son, one Spirit who are all one.
But the only way to explain how threeness remains one is simplicity. God is one spiritual nature with three subsisting persons that share all properties except relational distinctions, which exist substantially in God. Simplicity allows for oneness while having three distinct hypostaseis or persons.
So again simplicity makes sense of out the what and how of trinitarian persons. Reasoning back to the cause, which is simplicity, we can further say that simplicity fits what we know about God. It is a good summary of God.
Replies to objections
Reply to objection 1. As shown above, the doctrine of simplicity is biblical, and it follows from biblical affirmations. It also makes sense of the pattern of Scripture, namely, the testimony of the one God in three persons.
Reply to objection 2. God exists truly. And scriptural writers write according to their theological beliefs of God. We do not have access to their full set of beliefs. But we can see traces of their theology in what they write. So Moses records moving to Mount Sinai, dining with God on the mount along a heavenly pathway, and finally entering into God’s heavenly presence in which he saw the heavenly tabernacle (Exod 24). From this heavenly pattern, Moses instructed Israel to build an earthly replica.
The surface grammar of the text bespeaks what we might call metaphysical realities. Moses sees God’s inner realm and the true tabernacle. This reflects itself on earth. Others have noted how the tabernacle reflects the heavens and earth in its design. Here and other places in Scripture invite us to read the surface grammar to grasp deeper realities.
So we can read the traces of theology in the words of biblical authors to discern the causes of these traces and the effects of these traces. This is what we call theology. And it comes out of the surface grammar of the text.
Reading Scripture to discern the cause of one’s theology (God) rightly reads the literal or surface grammar of the text. We then can make necessary conclusions on this basis, which systematic theology often does.
Reply to objection 3. Immutability is true as the above argued.
Reply to objection 4. Time measures change. Since God does not change, as noted above, he is eternal and exists outside of what we call time.
Reply to objection 5. Properties of God reflect the one perfection of God. God’s simple nature is like a jewel which shines differently depending on the light’s angle. Therefore, God does not have properties like we do—as distinct measurable attributes. They are one with the divine essence of God. And that oneness grounds the perception of God’s multiple perfections.
Reply to objection 6. The biblical support for trinitarian relationships is strong, not weak. To say name the Logos in relation to God, the Image to the reality, or Son to Father bespeaks clearly a relationship between two persons. These relations find deeper explication in passages like John 5:26 which roots divine life in he Father and his eternal bestowal of life to the Son; or passages like John 16:14 which show that the Spirit takes of Son to declare the things of the Son.
Scripture and reason teach divine simplicity. It makes sense of what the Bible says, and it also helps to explain key realities like the worship of one God with a threefold name (Matt 28:19). It should, therefore, stand at the start of knowledge of God just as does in the Belgic Confession