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Gottfried Leibniz

Continental Rationalism · Europe · 1646 to 1716

German polymath who held that reality is made of simple mind-like units and that this is the best of all possible worlds.

What it is

Gottfried Leibniz (1646 to 1716) was a German philosopher, mathematician and diplomat, born in Leipzig and often called a universal genius. He held that reality is made of simple, mind-like units he called monads, and that the world we live in is the best one a perfect God could have created.

He worked in metaphysics, logic, the philosophy of religion, law, history, mathematics and physics, and spent most of his life in the service of German noble courts. That work let him travel widely and meet many of the best minds of his day.

The main ideas

  • Monads. The basic things in the world are not bits of matter but simple substances with no size or shape, which he called monads. Matter, on this view, is how those substances appear.
  • No contact between substances. Each monad is causally independent of every other. Nothing passes from one to another.
  • Pre-established harmony. If substances do not act on each other, why does my arm lift when I decide to lift it? His answer is that God made every substance so that its changes unfold in step with all the others from the start, like clocks set to agree.
  • Sufficient reason. Nothing happens without a reason why it is so and not otherwise. This, together with the principle that a thing cannot be and not be, drives much of his argument.
  • The best possible world. In his book on the goodness of God, the Theodicy (1710), he argued that a perfect God would choose the best of all possible worlds, and that this is how the existence of evil is to be understood.
  • Calculus. Alongside Newton he is credited with inventing the infinitesimal calculus.

What it looks like in practice

Picture someone who has lost their job and is told, kindly, that it all happens for the best. Leibniz did hold that this world is the best that could be, but his claim is about the whole, not about each person's luck: a world with some evils in it could still be better overall than any other. Whether that answer comforts, or only explains, is up to the person hearing it. This is an illustration of the idea, not a saying of Leibniz.

Books and moments

  • The *Theodicy* (1710) is the book that sets out the best-possible-world argument.
  • The *Monadology* is a short statement of the theory of monads.
  • The calculus dispute. In his last years he was caught in a bitter quarrel with Newton and Newton's followers over who invented the calculus. Most historians now think each worked it out independently.

Questions and criticism

  • Is this really the best world? Voltaire mocked the claim in his novel Candide, where a character repeats it like a mantra. The question is still whether such a claim explains evil or only explains it away.
  • Do bodies exist? Because he treated matter as an appearance of monads, many readers found the view hard to accept, and Bertrand Russell was among them.
  • Is pre-established harmony a good answer? It avoids saying that mind acts on body, but it asks us to accept that everything was set up in advance.

Close neighbours

He answered Descartes on how mind and body fit together, and he rejected the view of Malebranche that God directly causes every event. Kant is named among those he influenced. The page on Spinoza and the page on rationalism show other answers from the same period.

Written by epchē in our own words, and checked against independent sources on 9 October 2026. The sources are listed below.

Philosophies they belong to or are close to

Who they connect to

Influenced

  • Anton Wilhelm Amo · Amo studied at German universities where the philosophy of Leibniz and Wolff dominated. (scholars disagree about this link)
  • Gottlob Frege · Frege's aim of a precise formal language followed Leibniz's dream of a calculus of reasoning.
  • Moses Mendelssohn · He built his thought on Leibniz and the school of Wolff.

Influenced by

  • René Descartes · Leibniz took up and challenged Descartes' physics and philosophy of mind.

Reacted against by

  • Voltaire · Candide mocks the idea that this is the best of all possible worlds.

Other Continental Rationalism thinkers

Sources we used

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