A Philosophical Essay on Probabilities

A Philosophical Essay on Probabilities
AuthorPierre-Simon Laplace
Original titleEssai philosophique sur les probabilités
TranslatorFrederick Wilson Truscott; Frederick Lincoln Emory
LanguageFrench
SubjectProbability theory
Published1814
PublisherCourcier, John Wiley & Sons; Chapman & Hall
Publication placeFrance
Published in English
1902
TextA Philosophical Essay on Probabilities at Wikisource
Websitehttps://bayes.wustl.edu/Manual/laplace_A_philosophical_essay_on_probabilities.pdf

A Philosophical Essay on Probabilities (French: Essai philosophique sur les probabilités) is an 1814 work by Pierre-Simon Laplace presenting a wide-ranging account of the meaning of probability and the uses of the calculus of probabilities across the natural and moral sciences.[1] The essay became one of the best-known introductions to Laplace's approach to probability and statistical inference, and it is frequently cited in later discussions of the classical probability tradition associated with Laplace.[2]

The work is also known for a celebrated statement of determinism—later dubbed Laplace's demon—which imagines an intellect that could predict the future from complete knowledge of the present and the laws of nature.[3]

Background and publication

Laplace published the Essai in French in 1814, with early editions appearing in Paris through Courcier.[1] The essay was closely connected to Laplace's larger technical treatise, the Théorie analytique des probabilités (1812): later summaries and editions describe the Essai as originating as an introductory presentation of ideas developed in the treatise and related teaching in Paris in the mid-1790s.[4][5]

An English translation by Frederick Wilson Truscott and Frederick Lincoln Emory was published in 1902 (New York: John Wiley & Sons; London: Chapman & Hall).[6][7] Modern scholarly editions have also appeared, including a late-20th-century translation by Andrew I. Dale based on a revised French edition.[5]

Contents

The essay is divided into two parts. Part I introduces the concept of probability and general principles of the calculus of probabilities; Part II surveys applications, ranging from games of chance to questions in physics, social decision-making, law, and demography.[6]

Part I: A Philosophical Essay on Probabilities

Part I develops Laplace's broad philosophical framing of probability, including:

  • the meaning of probability and its relation to knowledge and ignorance,
  • general principles for calculating probabilities,
  • expectation (hope) and decision under uncertainty,
  • analytic methods used in probability calculations.[6]

Part II: Application of the Calculus of Probabilities

Part II applies probabilistic reasoning to diverse domains, including:

  • games of chance and unequal chances,
  • laws of probability under repeated events,
  • applications to natural philosophy,
  • applications to the "moral sciences" (including social and institutional settings),
  • the probability of testimony and judgments,
  • assemblies and collective decision-making,
  • mortality tables and the mean durations of life and marriage,
  • errors and "illusions" in estimating probabilities,
  • methods of "approaching certainty," and a historical note on the calculus of probabilities up to the early 19th century.[6]

Themes and notable ideas

Classical probability and the "equally possible cases" tradition

Later philosophical surveys often use Laplace as a central reference point for the classical interpretation of probability, which assigns probabilities by symmetry when outcomes are treated as "equally possible."[2] In this tradition, probability is defined by the ratio of favorable cases to the total number of cases under an assumption of symmetry or neutrality of evidence.[2]

Determinism and "Laplace's demon"

Laplace's discussion of determinism in the Essai became famous in the philosophy of science. A widely cited formulation imagines an intelligence for whom (given complete knowledge and sufficient computational power) "nothing would be uncertain and the future, as the past, would be present to [its] eyes."[3] Later writers commonly refer to this hypothetical intelligence as Laplace's demon and use it as a touchstone in debates about predictability, determinism, and the limits of scientific forecasting.[3]

Probability as a guide to reasoning under uncertainty

The essay is frequently discussed in modern overviews of probability's conceptual foundations because it treats probability not only as a mathematical calculus but also as a general tool for reasoning with incomplete information, spanning scientific, legal, and practical decision contexts.[4][6]

Reception and legacy

The Essai has been widely reprinted and has remained part of the historical canon of probability and statistics, in part because it combines philosophical interpretation with concrete examples of probabilistic reasoning across science and society.[4][2] Its early statement of the classical interpretation of probability and its association with Laplacean determinism have made it a recurring reference in philosophical and historical discussions of probability.[2][3]

Editions and translations

  • Laplace, Pierre-Simon. Essai philosophique sur les probabilités. Paris: Courcier, 1814.[1]
  • Laplace, Pierre-Simon. A Philosophical Essay on Probabilities. Translated by Frederick Wilson Truscott and Frederick Lincoln Emory. New York: John Wiley & Sons; London: Chapman & Hall, 1902.[6][7]
  • Laplace, Pierre-Simon. Philosophical Essay on Probabilities. Translated (and introduced) in a modern scholarly edition by Andrew I. Dale. Springer, 1995.[5]

See also

References

  1. ^ a b c "Essai philosophique sur les probabilités". Internet Archive. Courcier. 1814. Retrieved 2025-12-22.
  2. ^ a b c d e "Interpretations of Probability". Stanford Encyclopedia of Philosophy. 2023-11-16. Retrieved 2025-12-22.
  3. ^ a b c d Frigg, Roman; Smith, Leonard A.; Stainforth, Dave A. (2014). "Laplace's Demon and the Adventures of His Apprentices" (PDF). Philosophy of Science. Retrieved 2025-12-22.
  4. ^ a b c "Interpretations of Probability". Internet Encyclopedia of Philosophy. Retrieved 2025-12-22.
  5. ^ a b c Laplace, Pierre-Simon (1995). Philosophical Essay on Probabilities. Springer. Retrieved 2025-12-22.
  6. ^ a b c d e f "A Philosophical Essay on Probabilities (1902)". Wikisource. Retrieved 2025-12-22.
  7. ^ a b "A philosophical essay on probabilities". Internet Archive. J. Wiley & Sons. 1902. Retrieved 2025-12-22.
This article is issued from Wikipedia. The text is available under Creative Commons Attribution-Share Alike 4.0 unless otherwise noted. Additional terms may apply for the media files.