November 24, 1763

An Essay towards solving a Problem in the Doctrine of Chances

Bayes’s inverse-probability essay is presented to the Royal Society

A theorem now carrying Bayes's name reached the Royal Society more than two years after Bayes was buried.

23 December 1763, in London

At a Royal Society meeting in London on 23 December 1763, Richard Price presented the late Thomas Bayes's manuscript "An Essay towards solving a Problem in the Doctrine of Chances."

Bayes had died on 7 April 1761, about two years and eight months earlier. Price's covering letter to the fellow John Canton was dated 10 November 1763, but the printed paper records the reading as 23 December — not 24 November.

The problem the essay actually solved

The essay addressed the inverse-probability problem: using the observed number of successes and failures to calculate the probability that the unknown chance of success lies between specified limits.

As communicated it ran to 10 propositions and 3 rules. It appeared in Philosophical Transactions volume 53, pages 370–418; the volume is dated 1763, but the printing history dates actual publication to 1764.

How much of it is Bayes

Bayes's relatives asked Price to examine his papers after he died. Price found the probability manuscript, judged it worth preserving, and prepared an edited and expanded version for the Society, adding an appendix and interpretive material; a supplement followed in December 1764.

Almost all of Bayes's underlying notes are lost, so the surviving evidence does not permit every passage to be assigned confidently between the two men.

Calling this the first announcement of Bayes' theorem is anachronistically broad: the essay presents an inverse-probability result for a particular setting, not the modern identity in its usual general form. A passage David Hartley published in 1749 may describe Bayes's result, so private disclosure could have come earlier.

Sources

Researched 24 Aug 2026 6 sources not yet audited Date corrected

How this was checked

Researched from the web into a fact sheet and rewritten from that sheet. This article has not yet had an independent model audit. How the pipeline works →

Date corrected. The research places this at 1763-12-23.

What the sources leave uncertain

The listed date, 24 November 1763, is unsupported; the primary paper and scholarly histories give 23 December 1763 for the Royal Society reading.
Calling this the first “announcement of Bayes’ theorem” is anachronistically broad. The essay presents an inverse-probability result corresponding to a special setting, not the modern elementary identity in its usual general form.
How much of the published text and mathematics Price added remains a historical question because almost all of Bayes’s underlying manuscript notes are lost.
A passage published by David Hartley in 1749 may describe Bayes’s result, so private disclosure could have preceded the Royal Society presentation.