The Best of All Possible Worlds: Leibniz's "Monadology"

Gottfried Wilhelm Leibniz was a universal genius, a co-inventor of calculus, a diplomat, a logician, and one of the last people who could plausibly claim to know everything known in his time. His Monadology is a tiny book, just ninety short numbered paragraphs, in which he sketches an entire metaphysics, a complete picture of what reality is made of. It is dense, strange, and dazzling, the work of a mind trying to deduce the structure of the universe almost from first principles. And it is also, as Voltaire would later mock, the source of the famous and much-misunderstood claim that this is the best of all possible worlds.

Here is what the Monadology taught me about the simple substances called monads, about the harmony that holds the world together, and about the daring argument that this world is the best one possible.

Key takeaways

• Reality is made of “monads,” simple, indivisible, mind-like units of substance.
• Each monad mirrors the whole universe from its own point of view.
• Pre-established harmony: monads do not interact but are perfectly coordinated by God.
• This is “the best of all possible worlds,” chosen by a perfect God.
• The optimism is serious philosophy, not the naive cheer Voltaire satirized.

The universe made of monads

Leibniz starts from a logical worry: anything composite, made of parts, must ultimately be built from things that are not themselves composite, or there would be nothing real underneath. So reality must be made of simple substances, which he calls monads. But monads are not tiny bits of matter, for matter is infinitely divisible. They are immaterial, indivisible, mind-like points of force and perception. Everything that exists, in Leibniz’s vision, is ultimately composed of these countless simple, soul-like units. It is a wildly counterintuitive picture, a universe whose final building blocks are closer to minds than to atoms, and yet it follows with strange rigour from his starting premises. I found it less convincing than fascinating, a glimpse of how far pure reason can travel from common sense.

The mirror and the harmony

Two of Leibniz’s ideas struck me as genuinely beautiful. The first is that each monad mirrors the entire universe from its own unique perspective, like a city that looks different from every vantage point yet is one city. Every simple substance, however humble, reflects the whole of reality in its own way. The second is his solution to how these windowless monads, which cannot causally affect one another, nonetheless make up a coordinated world. His answer is the “pre-established harmony”: God, in creating the monads, set them in such perfect coordination that they unfold together like countless clocks all wound to keep the same time. The appearance of interaction is real harmony, arranged in advance. It is an audacious and elegant idea, even if one cannot quite believe it.

The best of all possible worlds

The most famous and most ridiculed of Leibniz’s conclusions is that this is the best of all possible worlds. The argument is more serious than its reputation. A perfect God, Leibniz reasons, surveying all the infinitely many possible worlds he could create, would necessarily choose to create the best one. Therefore the actual world, despite its evils, must be the optimal balance of richness, order, and goodness that is logically possible; the evils it contains are the unavoidable cost of the greatest overall good. Voltaire savaged this in Candide, and the optimism can indeed sound callous in the face of real suffering. But Leibniz is not saying everything is wonderful. He is making a careful claim about what a perfect creator would do, and the problem he is wrestling with, how to reconcile a good God with a world of evil, is a genuine and enduring one.

What I’m taking with me

The Monadology is a monument to the reach and the limits of pure reason. I do not believe the universe is made of monads, and I share some of Voltaire’s resistance to the optimism. But what I am taking from Leibniz is admiration for the audacity of the project, the attempt to deduce the whole structure of reality with rigour and consistency, and a few ideas of real beauty: the monad that mirrors the whole, the harmony that binds a world of separate points of view. Even where I cannot follow him, Leibniz reminds me how strange and how grand the question “what is reality made of?” really is.

Frequently asked questions

What is Leibniz’s Monadology about?

It is a short work setting out Leibniz’s metaphysics: that reality is composed of simple, immaterial, mind-like substances called monads, coordinated by a divine pre-established harmony into a single ordered world.

What is a monad?

For Leibniz, a monad is a simple, indivisible, immaterial unit of substance, somewhat like a mind or point of perception. Everything that exists is ultimately composed of monads.

What did Leibniz mean by “the best of all possible worlds”?

That a perfect God, choosing among all possible worlds, would create the best one, so our world, despite its evils, must be the optimal balance of good that is logically possible. Voltaire famously satirized this idea.

References & further reading

1. Leibniz, Gottfried Wilhelm. Monadology. 1714.
2. Russell, Bertrand. A Critical Exposition of the Philosophy of Leibniz. Cambridge University Press, 1900.
3. Rescher, Nicholas. Leibniz: An Introduction to His Philosophy. Blackwell, 1979.