The Simple Light

Dante Alighieri spent his last years in exile, finishing a poem that walks one man through Hell, up the mountain of Purgatory, and into Heaven. Giovanni Boccaccio tells a story that the final thirteen cantos were missing when Dante died in Ravenna in 1321. Months later, the story goes, Dante appeared to his son Jacopo in a dream and showed him a niche in the wall of his old bedroom, hidden behind a mat. There they were, moldy with damp. It is probably too good to be true. It fits anyway, because the last canto is about a man who sees something and cannot bring it back.

At the end of the Paradiso, the pilgrim Dante stands at the top of everything. The old monk Bernard smiles and signals him to look up. He is already looking. What he sees is a light, and inside the light, the whole world:

In its depth I saw ingathered, bound by love in one single volume, that which is dispersed in leaves throughout the universe: substances and accidents and their relations, as though fused together in such a way that what I tell is but a simple light.

Everything that lies scattered across creation, like pages torn from a book and blown down the street, is gathered back into one bound book. Things, their features, and the ways they connect are “fused together.” And yet the thing he sees is “a simple light.”

Then the light shows him more. Three circles, “of three colors and one magnitude,” one seeming to reflect the other “as rainbow by rainbow,” the third like fire breathed out by both. Inside the second circle he sees a human face, painted in the circle’s own color. He wants to understand how a human shape can have its place inside that circle, and he cannot:

As is the geometer who wholly applies himself to measure the circle, and finds not, in pondering, the principle of which he is in need, such was I at that new sight.

The geometer is trying to square the circle: to build, with only a compass and a straightedge, a square with exactly the same area as a given circle. Nobody in Dante’s century knew it, but the job is impossible. Ferdinand von Lindemann proved that in 1882, when he showed that pi is a transcendental number. Dante reached for the perfect picture of a problem that feels like it should work and never will. Then a flash strikes his mind, his wish is answered in a way he cannot report, and the poem ends with his will turning “like a wheel that is evenly moved, by the Love which moves the sun and the other stars.”

Where the Opposites Go

Start with a belief you probably hold. You likely hold it because it sounds wise.

Down here, things come in opposites. Hot and cold. Light and dark. Life and death. One and many. War and peace. Good and evil. A great deal of human trouble comes from these pairs pulling against each other, inside us and between us. And at the top, whatever the top is (God, the Absolute, reality seen whole), the pulling has to stop. There seem to be two ways that can happen.

The first way is war with a winner. Light and dark are two real powers in a real fight, and the highest good is the light, which will win. The Persian prophet Zoroaster taught something close to this. In the third century a Persian named Mani built a whole religion on it: two eternal principles, one good and one evil, tangled together in our world and slowly being sorted apart. For nine years a young North African named Augustine was one of Mani’s followers. The picture is simple, and it gives you a clear job. Pick the right side.

The second way is peace by blending. The fight is an illusion of small minds. From high enough up, light and dark are two halves of one whole, and each one needs the other. The Greek philosopher Heraclitus said it around 500 BC, in a line that still sounds modern:

God is day night, winter summer, war peace, satiety hunger.

In the Greek there is no “and” between the words. God is not day plus night. God is day-night, one thing seen from two sides. The same idea sits in the yin-yang symbol, where each half carries a dot of the other. It sits in a hundred sermons and self-help books that tell you the darkness is part of the light. It even sits in Star Wars, where fans still argue about the prophecy that Anakin Skywalker would “bring balance to the Force.” One popular reading says balance means light and dark in equal measure, each keeping the other honest.

Of the two answers, the second sounds grown-up. The first is a cartoon with heroes and villains. The second is what you come to believe after you’ve lived a while. People you love have faults. Failure teaches. Grief deepens joy. The second answer seems humble and generous, and it seems to match Dante’s vision exactly: everything “fused together” in one light.

So here is the belief, put as plainly as possible. Opposites are pairs of things that shut each other out. At the top of reality they must either be fought out, with one side winning, or held together, with both sides kept in balance inside one whole. And the second answer is the deeper one.

That belief has a flaw in its first sentence. “Opposites are pairs of things that shut each other out” assumes there is one kind of opposite. There are at least four. The old argument about what happens to opposites at the top of reality turns out to be an argument about which of the four kinds gets in. The two thinkers who fought hardest over it, Thomas Aquinas and G. W. F. Hegel, both let opposition into God. They let in different kinds, and that difference decides whether evil is something God needs.

Four Ways to Be Opposite

In Plato’s Protagoras, Socrates gets his rival to agree that “everything has one opposite and not more than one.” It sounds obvious. Hot has cold. Up has down. Plato’s student Aristotle took the idea apart. In a short book called the Categories he sorted opposites into four kinds, and the list is the key tool for everything that follows.

First, contraries. Hot and cold, black and white, odd and even, just and unjust. These are two positive qualities that can’t be in the same thing at the same time in the same way. Aristotle noticed that contraries always live inside a family, which he called a genus. Only numbers are odd or even. Only people, laws, and acts are just or unjust. A rock is neither. Contraries are opposites inside a kind.

Second, contradictories. Just and not-just. “It is raining” and “it is not raining.” One side is simply the denial of the other. These need no family. Everything in the universe is either just or not-just, and a rock counts as not-just only because it isn’t the kind of thing that could be just. Contradictories allow no middle and no blend. One side is true and the other false, every time. Bertrand Russell, who otherwise disagreed with Aristotle about plenty, put the point sharply: “the law of contradiction is about things, and not merely about thoughts.” It governs what can exist, as well as what can be said.

Third, possession and privation. Sight and blindness. Health and sickness. Here one side is a real feature and the other is its absence in a thing that ought to have it. A blind man lacks sight. A stone isn’t blind, even though it can’t see, because a stone was never supposed to see. Blindness isn’t a second thing standing across from sight. It is a hole where sight should be.

Fourth, correlatives. Double and half. Parent and child. Teacher and student. These face each other, and they are never the same, but each one needs the other to exist at all. You can’t be a parent without a child. Nothing is double unless something is half. Correlatives don’t fight. They define each other.

With the list in hand, the question “what happens to opposites at the top?” splits into four questions with four different answers.

Contradictories can’t be reconciled by anyone, God included. A thing cannot both be and not be in the same respect. Almost every serious thinker on the subject, whatever else they believed, agreed on that much, and the few who seem to deny it turn out, when you read closely, to be doing something else with the words.

Correlatives don’t need reconciling. They were never enemies. The parent and the child are already together. That’s what the words mean.

Contraries need a family to fight in. Hot and cold are opposites only because both are temperatures. Take away the family and the fight has nowhere to happen.

Privations aren’t a second thing at all. You don’t reconcile health and sickness by blending them. Sickness is health gone missing, and the cure is health coming back.

Now go back to the two answers from before. “One side wins” treats every pair like contraries at war. “Both sides are held in balance” treats every pair like correlatives, each side needing its partner the way a parent needs a child. The balance answer feels wise because it borrows the gentleness of correlatives. But are good and evil correlatives? Is evil good’s partner, the way half is double’s partner? Or is it good’s absence, the way blindness is sight’s? The Star Wars argument has a second camp, the one that says the dark side was never a proper half of anything. It was the thing knocking the Force off its center, and “balance” meant removing it. Those fans are having, without knowing it, one of the oldest arguments in philosophy.

What Aquinas Meant by Simple

Thomas Aquinas wrote his Summa Theologiae in the 1260s and early 1270s, and one of its first moves is a strange act of restraint. Having argued that God exists, he stops and says what he can’t do next:

Because we cannot know what God is, but rather what He is not, we have no means for considering how God is, but rather how He is not.

So he works by subtraction. He lists every way a thing can be made of parts, and he denies each one of God. God is not a body with parts. God is not matter plus form. God is not a nature plus an individual who has it, the way a man has humanity. God is not an essence plus the fact of existing. God is not a thing plus its features. Aquinas calls the result God’s simplicity, and he means it in the old sense of the word: having no parts, not being made of anything.

One of those denials matters most here. God is not in any genus. Aquinas borrows an argument from Aristotle: being itself can’t be a genus, because a genus gets divided by differences, and there is no difference outside of being to divide it with. “Non-being cannot be a difference.” So God, who is being itself, sits in no family at all:

He has no genus nor difference, nor can there be any definition of Him.

Put that next to Aristotle’s rule that contraries always live inside a genus. The result is sharp. God has no contrary. Nothing is to God what cold is to hot. Not the devil, who in this picture is a creature who went wrong, and not nothingness either, which isn’t a rival power but simply nothing. The classical God does not beat an opposite. The classical God is not the kind of thing that can have one.

The same goes for the features that pull against each other in us. A judge feels justice and mercy tugging in two directions, because in him they are two separate traits. Aquinas says that in God they are not traits at all. Words like wisdom and virtue “are not said of God and of us univocally,” meaning they don’t mean exactly the same thing in both cases. We have many words for God because of “the diversity which lies in the way our intellect receives, and not to any diversity in reality.” Picture many windows onto the same sun. The windows are different. The sun isn’t.

Then why is the world so crowded with different things, many of them at odds? Aquinas takes that up directly, and his answer is the heart of the one-and-many question:

With us composite things are better than simple things because the perfection of created goodness cannot be found in one simple thing, but in many things. But the perfection of divine goodness is found in one simple thing.

In plain terms: no single creature can show everything good. A world with only one kind of good thing would be a poor world. So the goodness that is one in God gets spread out in creation across countless things, each carrying a piece. The many is a translation, the only way finite things can show what is whole in God. Aquinas quotes the fourth-century bishop Hilary of Poitiers to make the point: “God, Who is strength, is not made up of things that are weak; nor is He Who is light, composed of things that are dim.” Light is not a blend of light and dark. That is what Dante means by “a simple light.”

And evil? This is where Augustine comes back in. After his nine years with Mani, he found in the Platonists a way out of the two-gods picture, and he wrote it down in his Confessions: “whatever is, is good,” and evil is not a substance at all. Evil is damage. It is what’s missing in a thing that should be whole, the blindness in the eye. Aquinas builds on that. So the classical God is not the balance point between good and evil. There is nothing on the other pan of the scale.

This picture has modern critics, and they are serious. Alvin Plantinga argued in 1980 that strict simplicity makes God into something like an abstract property rather than a person. Others press on the privation theory and ask whether cruelty is really just a lack, since it can feel like a force with its own drive. The picture is still the classical one, held by Augustine and Aquinas and written into the Reformed confessions, where the Westminster Confession calls God “without body, parts, or passions.” But it is contested ground, not settled fact.

Its sharpest rival came earlier than Hegel. In 1677 Baruch Spinoza published his Ethics, which answers the one-and-many question the other way:

Whatever is, is in God, and nothing can either be or be conceived without God.

Spinoza goes so far as to say that “God is an extended thing,” that physical space is one of God’s attributes. He explains it with water. We think of water as divided into parts, and as water it is. But “in so far as it is corporeal substance,” it is “neither separated nor divided.” The many are the one, seen piece by piece by the imagination. Aquinas had already named this family of views and rejected them. Some said God is the soul of the world. Some said God is the form of all things. One medieval thinker, David of Dinant, “most foolishly taught that God was prime matter.” Against all three, Aquinas holds that the first cause “rules all things without commingling with them.”

That is where the whole question turns. Where the many live decides where the opposites live. If the world is inside God, the world’s contraries are inside God. If the world is made and stands outside God, they aren’t. The classical answer was never “pick the winning side.” It was that the highest thing is not a piece on the board where sides exist. J. R. R. Tolkien, a Catholic who took this picture seriously, dramatized it in The Silmarillion: when the rebel Melkor fills the first music of creation with his discord, the creator Ilúvatar tells him that “no theme may be played that hath not its uttermost source in me, nor can any alter the music in my despite.” Melkor isn’t Ilúvatar’s opposite number. He is one of the singers.

Hegel’s House

G. W. F. Hegel, lecturing in Berlin in the 1820s, thought the classical answer was too thin, and his reasons deserve a fair hearing.

The simple God stands apart from the world, untouched by it. The world’s suffering never reaches him. History looks like a pile of accidents, and “providence” shrinks to what Hegel scornfully called the “peddling” view: God helps this person find a job, sends that one a lucky break. Hegel wanted more. He wanted the whole of history to make sense, and he said so bluntly: “we must not imagine God to be too weak to exercise His wisdom on the grand scale.” For that, he needed God and the world, and all the world’s contraries, to belong to one story.

So Hegel let the negative into God. Discussing the ancient worship of Adonis, the god who dies young and is mourned and found again, he says it shows that “the negative itself is a phase of deity.” When he reaches Christianity, he states the whole idea:

Spirit makes itself its own opposite and is the return from this opposite into itself.

God goes out into what is other than God, the finite world with its limits and death and pain, and comes back to himself enriched. And the world isn’t left outside: “finite spirit itself therefore is posited as a constituent element in the divine being.” Suffering, too, gets a place in the plan: “suffering itself is henceforth recognized as an instrument necessary for producing the unity of man with God.” Christianity’s great loss, God dying, becomes its great gain. “The infinite loss is counterbalanced only by its infinity and thereby becomes infinite gain.”

He had a homely picture for how opposites combine. When we build a house, we use fire, wind, and water to shape iron and cut wood. Then the finished house shuts those same elements out: “The wind, which has helped to build the house, is shut out by the house.” The forces are used “in accordance with their nature,” yet cooperate to make something that limits them. Opposition, taken up into a higher unity. That is the synthesis.

There is something grand here, and even Hegel’s harshest critic admitted it. Bertrand Russell wrote that “in this conception, there is undeniably something sublime, something to which we could wish to yield assent.” If Hegel is right, no loss is wasted. Every defeat is a step. It is the most generous account of suffering anyone has offered, and it looks like Dante’s vision exactly: everything fused into one.

A fair warning belongs here. Hegel is hard, and his readers disagree about what he meant. Many recent scholars, such as Robert Pippin and Terry Pinkard, read him less as describing a cosmic God-mind and more as giving a theory of how reason and communities come to understand themselves. What follows is the older, metaphysical reading, the one Russell attacked and the one these lectures invite when they speak of God, providence, and the Trinity.

On that reading, look at which kind of opposite Hegel is using. His system treats every opposition the way we treat correlatives. Being and nothing, finite and infinite, God and world: each side “requires” the other, the way a parent requires a child. That’s the gentlest of Aristotle’s four kinds, spread over all of them. And once good and evil are handled that way, the negative becomes load-bearing. Hegel never calls evil good. He calls it “a subordinate and vanquished nullity.” But in his own lectures he names what the process cost. He speaks of history as “the slaughter-bench at which the happiness of peoples, the wisdom of States, and the virtue of individuals have been victimized,” and he asks what final aim “these enormous sacrifices” served. His answer is that they served the unfolding of spirit. The sacrifices were not wasted. They were needed.

Here the classical side has an objection it must face honestly, because it seems to say the same thing. Augustine wrote, and Aquinas repeats, that God “would not allow any evil to exist in His works, unless His omnipotence and goodness were such as to bring good even out of evil.” Ilúvatar tells Melkor that his discord will “prove but mine instrument in the devising of things more wonderful.” Both pictures use evil for good. So what’s the difference?

The difference is between a rescue and a recipe. In the classical picture, God would be wholly God if there were no world at all, and a world with no sin was possible. When good comes out of evil, it is salvage: God repairing damage he did not need. In Hegel’s picture, spirit that never went out into its opposite would not be spirit. The negative is an ingredient, not an accident. Take it away and God is less than God. That is what it costs to let every kind of opposite in.

Russell’s objection goes straight to the gears. Hegel’s argument, he says, is like a comparative anatomist who looks at one bone and reconstructs the whole animal. Every piece of reality has “hooks which grapple it to the next piece,” until the whole universe is rebuilt from any fragment. For that to work, everything a thing is related to has to be part of what the thing is. And that, Russell says, is a confusion: “a truth about a thing is not part of the thing itself.” His example is a toothache. I can know my toothache completely, as completely as anything is ever known firsthand, without knowing what the dentist could tell me about its cause. The ache is fully mine without those facts. Most relations, in other words, are not like parent and child. They don’t make the thing what it is. If that’s right, you can’t turn every opposition into a correlative, and the machine that makes every opposition into a synthesis stalls.

So the answer that sounded humble and generous, “the darkness is part of the light,” turns out to be the one that needs the darkness. The cartoon of war with a winner was too simple. The picture of balance is worse in a quieter way. It makes the dark side a structural part of the whole, and it gives every slaughter-bench a place in the plan.

The Edge of What Theology Claims

One more difference between the two pictures decides the rest: what each one claims to know.

Hegel insisted that God can be known, fully, by thinking. He attacked “the pious modesty which puts far from it the knowledge of God,” and he wrote that “God wishes no narrow-hearted souls or empty heads for His children.” That confidence isn’t a side feature of his system. It is the system. For Hegel, the process by which opposites turn into each other and get taken up into higher unities is reason’s own motion. The Absolute is where reason arrives when it has thought everything through. A God reached that way has to be made of steps that reason can climb, contradiction by contradiction. So the negative has to be inside, because the negative is how the climbing works.

The classical tradition drew the lines of theology differently. It split theology into two kinds. Natural theology is what reason can reach alone, and Aquinas thought reason could reach a good deal: that God exists, that God is one, that God is simple. Sacred theology rests on revelation, and it holds truths reason cannot reach on its own. The chief example is the Trinity. “It is impossible,” Aquinas wrote, “to attain to the knowledge of the Trinity by natural reason.” Dante puts the same warning in the mouth of Virgil in the Purgatorio: “Foolish is he who hopes that our reason may compass the infinite course taken by One Substance in Three Persons.”

And here is where the classical picture turns out to be stranger than it first looked. It did let opposition into God. It let in exactly one kind.

The Christian doctrine of the Trinity says there is one God in three persons: Father, Son, and Spirit. What makes them three, if God is simple? Aquinas’s answer is that they are distinguished only by relations. The Father is Father only toward the Son. The Son is Son only toward the Father. And a relation of this sort, he says, carries opposition in it. In God there is real distinction “not according to that which is absolute,” meaning the one divine nature, “but according to that which is relative.” He calls it relative opposition. In Aristotle’s list, it is the correlative: parent and child, giver and receiver.

Run through the four kinds one last time. Contraries are shut out, because God is in no genus. Privation is shut out, because God lacks nothing. Contradiction is shut out, because nothing can both be and not be. Correlation is let in, and only there, at the very center, in the one place reason cannot reach by itself.

So both of the great reconcilers borrowed the same tool. Hegel took correlation, the kind of opposition where each side needs the other, and spread it over everything, God and world, good and evil, being and nothing. In return he got a God that reason can fully know and a world where every loss counts, at the price of making the negative a part of God. Aquinas kept correlation inside God, giving and receiving between persons, and refused to extend it to good and evil or to God and the world. In return he got a God with no dark half, at the price of admitting that the one opposition inside God is beyond what argument can prove. Within these two systems, at least, the two things come as a package: the God you can fully comprehend is the one with the negative built in, and the God with no negative is the one you cannot comprehend.

Nicholas of Cusa, a fifteenth-century cardinal, came at this from the geometer’s side. In On Learned Ignorance, finished in 1440, he pointed out that as a circle gets bigger, its edge gets flatter, and a circle of infinite size would have an edge that is a straight line. At the infinite, curve and straight coincide. Opposites meet. It sounds like Hegel’s dream. But later, in On the Vision of God, Cusa described that coincidence of opposites as a wall surrounding the place where God is found. Reason can reach the wall. It can see that opposites meet there. It cannot walk through.

The Geometer

Go back to the top of the Paradiso and read it again with the tools in hand.

“Substances and accidents and their relations, as though fused together in such a way that what I tell is but a simple light.” The first time through, “fused together” sounds like balance, everything blended into one. But Dante says as though fused, and what he actually sees is simple: no parts, no features added on, no genus. It is the scattered pages of the universe seen in the one place where they were never scattered. A few lines later he says so outright: “outside of it that is defective which is perfect there.” Out here, goodness is spread thin across many things, and some of it is damaged. There, it is whole. Nothing dark was mixed in to make it whole.

Then the three circles, “one seemed reflected by the other, as rainbow by rainbow.” A reflection is the plainest correlative there is. There’s no reflection without something reflected, and nothing reflected without the reflection. Two faces toward each other, neither one the other, neither one against the other. That is the only opposition in the light.

Then the human face inside the second circle, and the geometer who can’t find the principle. What Dante wants to understand is how a creature, with all the contraries and losses a human life carries, can have its place inside that light without the loss becoming part of the light. It’s the question Hegel answered by letting the negative in. Dante doesn’t answer it. He gets a flash, and his tongue fails, and he tells us so. It is the honesty of a man who knew which kind of opposite he had seen.

And the book was “bound by love,” and the last thing that moves is “the Love which moves the sun and the other stars.” Not balance. Balance needs both sides to stay. Love needs only that the other be there.