Physicist/statistician Edwin T. Jaynes, in a broad overview of the history of ideas about reasoning amidst uncertainty (precursors to Bayesian inference), attributes an early articulation of an important principle of reasoning to Herodotus, as follows (reference below):

Herodotus, in about 500 BC, discusses the policy decisions of the Persian kings. He notes that a decision was wise, even though it led to disastrous consequences, if the evidence at hand indicated it as the best one to make; and that a decision was foolish, even though it led to the happiest possible consequences, if it was unreasonable to expect those consequences.

Others have cited Jaynes' attribution of this principle to Herodotus (e.g., Devinder Sivia, in his tutorial text on Bayesian statistics; he mistakenly cites the passage as a quote from Herodotus).

Where does Herodotus make this observation? I suspect Jaynes is paraphrasing observations Herodotus makes less tersely and less directly. I'm guessing Jaynes is referring to observations in Herodotus' Histories. I've done some searching and skimming of Histories, but with no luck finding something citable (I confess I haven't read Histories in full; depending on the version, it's 600 to 800 pages).

Can anyone point to a particular passage in Herodotus' writings where he makes this observation?


  • E. T. Jaynes, "Bayesian Methods: General Background," in Maximum Entropy and Bayesian Methods in Applied Statistics (1986); at Camb. U. Press, and at Wash. U.

  • D. Sivia & J. Skilling, Data Analysis: A Bayesian Tutorial (2006), p. 4; at Oxford U. Press

  • Herodotus, The History of Herodotus (trans. G. C. Macaulay); one of several translations; HTML text available at Gutenberg.org (Vol. I & II)

  • 2
    The initial post lacked a link to the second volume; ironically, that's precisely where the relevant quotes are found.
    – Lucian
    Nov 7, 2021 at 15:03

1 Answer 1


Macaulay, 1890 the counsel which has been taken is no less good, though it has been defeated by fortune; while he who took counsel badly at first, if good fortune should go with him has lighted on a prize by chance, but none the less for that his counsel was bad.

Godley, 1920 A well-laid plan is always to my mind most profitable; even if it is thwarted later, the plan was no less good, and it is only chance that has baffled the design; but if fortune favor one who has planned poorly, then he has gotten only a prize of chance, and his plan was no less bad.

Herodotus, VII Histories 10D:2

Macaulay, 1890 the matter which is wisely planned has for the most part a good issue afterwards.

Godley, 1920 in general a well-laid plan leads to a happy issue.

Herodotus, VII Histories 157:3

  • Brilliant! Thanks @Lucian so much for the quick and very helpful reply!
    – Tom Loredo
    Nov 8, 2021 at 15:39

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