Divine simplicity
God has no parts · simplicity of God
The doctrine that God has no parts of any kind — not physical, not metaphysical — so that God's attributes are not components God possesses but are identical with God and with each other. It is what keeps God from being a being among beings.
In practice
It is the strongest version of a familiar move: refusing to let the thing you are explaining be assembled from anything more basic, because whatever assembled it would then be the better candidate for what you were looking for.
The common mistake
Hearing it as a claim that God is simple to understand. It says the opposite — that God is without composition, which is precisely why ordinary predicates do not apply in their ordinary sense and why the doctrine makes theology harder rather than easier.
Anything with parts depends on its parts. It would not be what it is without them, and something has to account for their being arranged as they are.
That is the whole engine of the doctrine, and it runs quickly. If God had parts, God would depend on them, and whatever put them together would be prior to God — so it, and not God, would be the ultimate explanation. A composite God is a God with something behind him.
So the classical tradition — Augustine, Maimonides, Avicenna, Aquinas — concluded that God has no parts of any kind whatever, and meant it far more strictly than the phrase suggests.
How strict
Not merely that God is immaterial. The denials go much further.
No distinction between God and God's attributes. God does not have goodness, power and knowledge as properties. God is goodness, and is power, and is knowledge.
No distinction among the attributes. Since each is identical with God, each is identical with the others. God's mercy and God's justice are not two things that must be balanced against one another. They are one thing under two names.
No distinction between essence and existence. In everything else, what a thing is and that it is come apart — you can know what a unicorn is without there being any. In God, essence and existence coincide, which is why Aquinas glosses the divine name as ipsum esse subsistens, being itself subsisting.
This is what people mean when they say classical theism does not regard God as the largest item in the universe. Simplicity is the technical content of that claim.
The two bills
The doctrine is not free, and its costs are the substance of most modern objections.
The predicates go strange. If God's mercy is identical to God's justice, then God is merciful and God is just have the same truthmaker, and it becomes unclear what either sentence adds. Asking God to be merciful rather than just is then not a request that could be granted, because there is nothing there to be one rather than the other.
This is exactly the pressure that produces the analogy of being. Once simplicity has ruled out predicates applying to God in their ordinary sense, some account of how they apply at all becomes compulsory — analogy is not an optional refinement but the repair the doctrine requires. It is also why apophatic theology, which speaks of God mostly by denial, runs alongside it so consistently.
Modal collapse. This is the sharper objection. God's act of creating is, by simplicity, identical with God's essence. God's essence is necessary. So God's act of creating is necessary — and the world could not have failed to exist.
That is the conclusion the doctrine was partly built to avoid, arriving by the back door. It is the same result as emanation, reached by a tradition that rejected emanation precisely because it made the world necessary. Defenders answer that the identity holds on God's side without transmitting necessity to the effect, which is a real position and not an obviously comfortable one.
Why it is still held
Because the alternative is harder than it looks.
Drop simplicity and God becomes a composite: a thing with properties, standing in relations to abstracta, made to be as it is by the arrangement of its constituents. Every question that was supposed to stop at God restarts one level up — why these attributes, in this combination, and what accounts for their holding together.
That does not make the doctrine true. But it explains why people who understood the objections perfectly well kept paying the bill, and it is the reason the argument has been live since the ninth century without either side running out of material.
Concept web
Open the full webQuestions
What is divine simplicity?
The doctrine that God has no parts of any kind, so God's attributes are not components God possesses but are identical with God and with one another. It follows from the argument that anything composite depends on its parts and on whatever arranged them.
What is the modal collapse objection?
That if God's act of creating is identical with God's necessary essence, then creation is necessary and the world could not have failed to exist. Critics take this to collapse the distinction between God and the world that the doctrine was meant to protect.
Why does divine simplicity require analogy?
Because if God's mercy and justice are identical with each other and with God, ordinary predicates cannot apply to God in their ordinary sense. Some account of how they apply at all becomes compulsory, and analogical predication is the classical answer.