In which the last great polymath builds a universe from windowless mirrors, invents calculus on the side, and insists that God chose the best of all possible worlds — even this one
♦ ♦ ♦Let’s see what already lives in your mind about Leibniz, monads, and the problem of evil.
Any names, dates, discoveries, or ideas connected to him...
The Problem of Evil. If God is all-powerful and all-good, why does suffering exist? Why do the innocent suffer? Why evil?
This is one of the oldest questions in philosophy and theology. Leibniz answered it directly in his Theodicy (1710): God could have created any world. God, being perfect, chose the best one. Therefore, this world—despite suffering—must be the best option available. Evil exists because free will is better than puppetry, and a world with freedom allows sin.
But notice: this is an argument. An intellectual answer. Later, when Jesus enters the story, he does not argue. He enters suffering. He weeps. He dies. The philosophical theodicy and the incarnational answer are profoundly different responses to the same question. Hold both in mind. By lesson's end, you will see why.
Gottfried Wilhelm Leibniz was born in Leipzig in 1646. His father was a professor of moral philosophy. His mother wanted him to be a priest. Instead, he became something rarer than either: a mind of such universal scope that he could credibly contribute to nearly every field of human knowledge. He was the last great polymath—the last person to master nearly all the learning of his age.
Leibniz was born in the chaos of the Thirty Years' War. Protestant and Catholic powers clashed. The new science was emerging—Galileo, Descartes, Newton. Leibniz was educated in classics, theology, and philosophy at Leipzig and Altdorf. By fifteen, he was exploring logic. By twenty-six, he had completed a law doctorate and written a dissertation on combinatorics.
He spent his career moving between courts. Diplomat. Librarian. Engineer. He traveled to Paris, where he met the greatest mathematicians of the age. He corresponded with nearly every major mind of Europe. He proposed schemes for peace, plans to reunite the churches, improvements to mathematics. Most of his ideas were never published in his lifetime. He died in 1716, nearly alone, largely unrecognized. It took centuries for the world to understand what he had done.
Leibniz's mature philosophy, especially in works like the Monadology (1714) and Theodicy (1710), rests on three revolutionary ideas. Let’s explore them one by one.
What is reality made of? Leibniz rejected both pure materialism and pure mechanism. He proposed something entirely new: the monad—a simple, indivisible, spiritual substance. Not physical atoms. Not abstract ideas. Monads.
Each monad has three astonishing properties:
Imagine you are a monad. You contain within yourself a complete perception of the entire universe. Every event that happens anywhere is perceived by you. But distant events appear to you as dim, unconscious perceptions. Your own body's sensations are bright and clear. You are isolated from every other monad, yet perfectly synchronized with them. You are a window onto infinity, closed to the outside but containing the whole.
This raises an obvious problem. If monads do not causally interact, how does anything work together? How do my thoughts align with my body movements? How does the universe form a coherent whole?
Leibniz's answer: Pre-established Harmony. God, at the moment of creation, coordinated all monads so perfectly that they operate in complete synchrony without ever touching each other. It is like a thousand clocks, each independent, all set to display the exact same time. Or like a thousand orchestras, each musician playing their score without hearing the others, yet all in perfect harmony because God pre-composed their pieces.
This is one of the most ambitious metaphysical solutions ever proposed. It preserves both the isolation of monads and the unity of the cosmos. But it is also deeply strange. If nothing touches anything, how can we act? How can we affect the world? Leibniz says we do affect it, but only in the sense that God has already pre-orchestrated everything so that our actions and their effects are synchronized—as if by divine watchmaking.
Now we come to the question that made Leibniz famous and then infamous. If God created the world, and God is all-good and all-powerful, why does evil exist?
Leibniz tackled this head-on in his 1710 work Theodicy—a full defense of God's justice. His answer rests on the Principle of Sufficient Reason: Everything that exists must have a reason for existing.
When God created the world, God faced an infinite set of possible worlds. God, being perfect, had to choose according to reason. Which world would a perfect God create? The best one. Therefore, this world—the actual world, with all its suffering—must be the best of all possible worlds.
Why is this the best? Because:
Leibniz's theodicy became famous—but not for the reasons he hoped. In 1759, nearly fifty years after Leibniz's death, the French satirist Voltaire published a novel called Candide. Its protagonist, Candide, follows a philosophical tutor named Dr. Pangloss, who insists throughout the novel that "all is for the best in this best of all possible worlds."
Over the course of the novel, Candide and Pangloss experience earthquakes, shipwrecks, slavery, disease, mutilation, and every conceivable form of human suffering. And through it all, no matter what happens, Pangloss repeats his mantra: "All is for the best."
Voltaire's satire is savage and brilliant. He shows that Leibniz's answer, while logically elegant, is morally obscene. It seems to excuse the inexcusable. It offers no comfort to someone actually suffering. It turns philosophy into something cynical and cruel. The novel devastated Leibniz's reputation. For centuries, Leibniz was remembered as the fool that Voltaire mocked.
Beyond his main philosophical work, Leibniz harbored grand dreams that mostly went unrealized:
Leibniz's philosophy is strange, intricate, and oddly modern. His ideas shaped mathematics, logic, and metaphysics for centuries. Let’s break down three core insights and see why they still matter.
Reality is not made of inert matter. It is made of simple, spiritual, perceptual units called monads, each reflecting the entire universe from its own perspective.
This is a radical departure from materialism. It says the world is not ultimately made of particles bouncing around according to mechanical laws. Matter is only appearance. Underneath is something more fundamental—spirit, perception, life.
Modern quantum mechanics echoes this in unexpected ways. Some interpretations (like the relational interpretation) suggest that properties of particles only exist relative to observers. Each particle is, in a sense, a perspective on reality. Leibniz was saying something like this in 1714.
Leibniz was trying to reconcile two insights: mechanism (the world follows laws) and vitalism (the world is alive). Monads are the reconciliation. Each is both alive and perfectly synchronized with mathematical law. This gives us a universe that is both rational and living.
Two things are identical if and only if they have exactly the same properties. Therefore, no two things in the universe can be exactly alike.
This sounds simple but has stunning implications. Because each monad has a unique perspective on the universe, each monad is absolutely unique. The universe contains infinite diversity. There are no duplicates.
This principle rules out certain symmetries and suggests that individuality goes all the way down. Leibniz used it to argue against the void and against absolute space. For him, space is not an empty container. Space is the order of things. And since every thing is unique, no two regions of space are identical. The universe is infinitely rich.
Nothing happens without a reason. God, being rational and perfect, chose to create the world that best satisfies all divine perfections—therefore, this is the best of all possible worlds.
This principle shapes how we think today. In science, we assume every event has a cause. In ethics, we demand justification. All of this comes partly from Leibniz. But it also forces a conclusion: if we accept Sufficient Reason fully, every evil must exist for a reason chosen by God.
Leibniz chose to interpret this comfortingly: God chose the best option available. But Voltaire and others found it monstrous. How can God's wisdom excuse suffering? How can we know that God chose the best? Is this not mere speculation?
Leibniz's theodicy is one of the most ambitious philosophical attempts to solve the problem of evil. But it leaves something crucial unresolved. Notice the stark difference between two answers to the same question:
The Philosophical Answer (Leibniz): Why does suffering exist? Because this is the best possible world. God could have created a world without free will, without suffering. But such a world would be inferior. Evil is a necessary feature of the optimal world.
The Incarnational Answer (Jesus): Jesus does not explain suffering. He does not argue: "Your pain is necessary for the best possible world." Instead, he enters suffering. He enters it as a human being. At Lazarus's tomb, he weeps. He does not defend God's justice philosophically. He demonstrates God's presence practically—by entering death, by suffering with us, by transfiguring suffering from within.
These are profoundly different responses. One is intellectual. One is personal. One tries to reconcile suffering with divine perfection through reason. One treats suffering as so real, so terrible, that the only adequate response is presence and solidarity and love.
Which is more true? Which is more adequate? That is one of the deepest questions a human can ask. And Leibniz, for all his brilliance, did not—could not—answer it. Because it requires not a philosopher, but a person. Not an argument, but a presence.
Three dates mark the trajectory of Leibniz's thought. Encode them using your PAO system. Split each year into two-digit pairs, find Person–Action–Object, then fuse them into vivid images.
The polymath is born during the Thirty Years' War. Encode “16” and “46” from your PAO. Link to a baby surrounded by books, mathematical symbols, mechanical gears—born into chaos and destined to master everything.
Leibniz publishes his defense of God and answer to the problem of evil. Encode “17” and “10” from your PAO. Link to God or an angel examining rows of snow globes (possible worlds), choosing the brightest, most perfect one.
The Monadology, his masterpiece. Encode “17” and “14” from your PAO. Link to millions of tiny mirrors suspended in infinite space, each reflecting the entire universe, none touching yet all synchronized.
Cover the dates above. Can you recall all three?
1. When was Leibniz born?
2. When was the Theodicy published?
3. When was the Monadology published?
You arrive at location 36. Behind you: Spinoza and the harmonious nature of being. Ahead: Hume, Rousseau, Kant—and the great age of Enlightenment. This location holds Leibniz, the last great medieval mind trying to reconcile reason with faith, logic with life, monads with God.
Your location holds The Best of All Possible Worlds. Place five vivid, impossible-to-ignore images here.
1. Millions of tiny mirrors, glittering and silent, each reflecting the entire cosmos—but none with windows, none touching each other — The monads. Perfect isolation. Perfect reflection. The strange isolation-within-unity that defines reality.
2. A divine watchmaker (God) setting thousands of clocks, adjusting them with infinite precision—all synchronized perfectly though they never touch — Pre-established harmony. The mechanism of cosmic coordination without causation.
3. An angel or divine figure examining rows of glowing snow globes on shelves, holding each up to light—choosing the brightest one — Theodicy. God examining infinite possible worlds and selecting the best.
4. Leibniz and Newton pulling a mathematical formula from opposite ends, both claiming victory, tears of frustration streaming down their faces — The calculus priority dispute. Two geniuses. One great idea. Bitter competition.
5. Dr. Pangloss (a caricature of Leibniz) standing in the rubble of Candide after an earthquake, smiling serenely, saying "This is the best of all possible worlds" — Voltaire's satire. The idea that made Leibniz famous for the wrong reason.
Describe exactly where each image lives in your chosen location. Make them vivid—color, size, motion, sensation, emotion.
Choose 2–3 questions to reflect on deeply. Write honest answers. There are no wrong answers.
Does Leibniz's answer comfort you? Does it make sense? Or does it seem to excuse suffering in a way that feels false when you confront real pain?
Reality is made of things that never touch each other. Yet somehow the universe works. Does this idea make sense? How? Or is it just clever philosophy without substance?
Voltaire's satire of Leibniz became more famous than Leibniz himself. Why did the satire work so well? Did Voltaire refute Leibniz, or just mock him?
Everything has a reason. Does this principle comfort or unsettle you? Does it leave room for freedom, chance, grace? Or does it close the universe into necessity?
How does a soul (a monad) govern a body (made of other monads) if they don't causally interact? What is Leibniz really trying to explain about the mind-body problem?
Leibniz dreamed of a characteristica universalis—a language in which all knowledge could be expressed and all disputes solved by calculation. Is this dream alive in computers? Should it be?
Leibniz answers "why evil?" with a philosophical argument. Jesus answers by entering suffering and death. Which response is more adequate? Can both be true?
Start the timer. Without looking back, write everything you can remember from this lesson. Go!
Retrieve from memory. Don’t look back at earlier tabs.
1646 — Birth of Leibniz in Leipzig
1710 — Publication of Theodicy
1714 — Publication of Monadology
What are the three key properties of monads?
Windowless: Monads do not causally interact. No doors, no windows. Complete isolation.
Mirror-like: Each monad perfectly mirrors the entire universe from its own perspective.
Alive: All monads possess perception and appetite. Even matter is composed of living monads.
Explain the concept. How does coordination happen without causation?
God, at creation, coordinated all monads perfectly. They synchronize without touching—like a thousand clocks showing the same time, or a thousand musicians in perfect harmony though they never hear each other. God pre-composed their scores.
How did Leibniz answer this ancient question?
God, being perfect, chooses from infinite possible worlds. God chose the best one. This world, with its suffering, is the best possible—because free will is better than puppetry, and freedom allows sin. Evil is the necessary price of the optimal world.
What surprised you most about Leibniz—the monads, the theodicy, the universal language, or something else? And what troubles you most about his answers?
In Lesson 37, we meet David Hume (1711–1776), the cheerful sceptic. He will quietly demolish causation, the self, miracles, and all certainty. He will dismantle the foundations of knowledge, then go to dinner and play backgammon. He died peacefully without God. His problem—that we cannot prove the future will resemble the past, that causation is never observed, only constant conjunction—has never been solved. It haunts all philosophy that follows.
This lesson's content returns in: Lesson 39 (+3), Lesson 43 (+7), and Lesson 50 (+14).