# Laplace's demon

> English word · Proper noun

## Definitions
1. A creature in a thought experiment that knows the precise location and momentum of every atom in the universe, and therefore (according to determinism) can compute their past and future values using the laws of classical mechanics.

## Etymology
First described in 1814 by Pierre-Simon Laplace.

## Source
Compiled from Wiktionary via kaikki.org (CC BY-SA). Data vintage: 2026-05-06.
Canonical page: https://plainspell.com/en/word/laplace-s-demon