Caption: Harold Jeffreys was one of the leading developers of Bayesian analysis---no relation though he manages to look a lot like the father of yours truly anyway.
See also Harold Jeffreys: Old/Young.
Bayesian analysis started with the discoverer and eponym of Bayes' theorem.
Pierre-Simon Laplace (1749--1827) and Harold Jeffreys (1891--1989) greatly extended it. Harold Jeffreys is one of the "cousins":
Credit/Permission:
Anonymous photographer,
circa late 20th century /
No permission.
Image link: MacTutor History
of Mathematics archive: Harold Jeffreys.
Local file: local link: harold_jeffreys.html.
File: Art file:
harold_jeffreys.html.