Gottfried Wilhelm Leibniz

Key ideas

Leibniz built his philosophy on the principle of sufficient reason: nothing happens without a reason why it is so and not otherwise. Applied to the universe as a whole, it led him to ask the question at the heart of why there is something rather than nothing, and to answer that the reason must lie in a necessary being outside the series of contingent things.

He also argued, in his famous mill passage, that perception cannot be explained mechanically: if you could walk inside a thinking machine as if into a mill, you would find only parts pushing one another, never a perception. The argument foreshadows the hard problem and the Chinese room.

His other ideas include the identity of indiscernibles (no two things can be exactly alike), a world made of mind-like simple substances he called monads, and the claim that God created the best of all possible worlds, which Voltaire mocked in Candide.

Life, briefly

Leibniz was the son of a Leipzig professor and worked for most of his life as a diplomat, historian and librarian to the dukes of Hanover. He discovered calculus independently of Newton, which led to a bitter priority dispute, and designed a calculating machine that could multiply.

He published relatively little in his lifetime and left behind a vast body of letters and manuscripts that are still being edited. He died in Hanover in 1716, largely neglected by the court he had served.

Major works

• Discourse on Metaphysics (1686)
• New Essays on Human Understanding
• Theodicy (1710)
• Monadology (1714)

Schools of thought

Rationalism

Further reading

• EncyclopediaStanford Encyclopedia of Philosophy: Gottfried Wilhelm Leibniz
• WikipediaGottfried Wilhelm Leibniz