📜 Theorem, law or theory

Bayes theorem

Teorema de Bayes

Date
1763 · confidence medium
Place
Tunbridge Wells, England
Credited to
Thomas Bayes (published posthumously by Richard Price); general form by Laplace (1774)
People
👤 Thomas Bayes1702–1761
Field
Knowledge & symbols

⚠️ Disputed: the sources disagree.

What was discovered

A rule for updating the probability of a hypothesis in the light of new evidence, by inverting conditional probabilities. It is the basis of probabilistic inference.

Laplace independently rediscovered and generalised the result in 1774 and was the one who applied it systematically.

What it led to

  • Bayesian statistics
  • machine learning
  • spam and Kalman filters
  • evidence-based medicine

Built on

  • Pascal-Fermat probability
  • Ars Conjectandi

Made possible

  • Enigma decryption (Turing, Bayesian)
  • probabilistic artificial intelligence

📄 Original publication

LII. An essay towards solving a problem in the doctrine of chances. By the late Rev. Mr. Bayes, F. R. S. communicated by Mr. Price, in a letter to John Canton, A. M. F. R. SThomas Bayes · Philosophical Transactions of the Royal Society of London · 1763

Links

Sources✓ verified 2026-09-25