# Alex Peek blog

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Saturday, May 20, 2017

## Pierre-Simon Laplace and probability theory

Photo source: Wikimedia Commons, Sophie Feytaud

Pierre-Simon Laplace (1749-1827) was an influential mathematician and scientist best known for his contributions to probability theory and celestial mechanics. Mathematician Morris Kline said,

"Laplace created a number of new mathematical methods that were subsequently expanded into branches of mathematics, but he never cared for mathematics except as it helped him to study nature." (Mathematical Through from Ancient to Modern Times, 1972)

Journalist Kathryn Schulz said,

"Pierre Simon Laplace refined the distribution of errors, illustrated by the now-familiar bell curve... Laplace used the bell curve to determine the precise orbit of the planets... By using the normal distribution to graph... individually imperfect data points, Laplace was able to generate a far more precise picture of the galaxy... aggregate enough flawed data, and you get a glimpse of the truth." (Being Wrong: Adventures in the Margin of Error, 2011)

The rest of this post is some quotes from Laplace.

### Probability

"The theory of chance consists in reducing all the events of the same kind to a certain number of cases equally possible..." (Philosophical Essay on Probabilities, 1812)

"The most important questions of life... are indeed for the most part only problems of probability." (Philosophical Essay on Probabilities, 1812)

### Expansion of knowledge

"All these efforts in the search for truth tend to lead it [the human mind] back continually to the vast intelligence... but from which it will always remain infinitely removed." (Philosophical Essay on Probabilities, 1812)

"Imaginary causes have gradually receded with the widening bounds of knowledge and disappear entirely before sound philosophy, which sees in them only the expression of our ignorance of the true causes." (Philosophical Essay on Probabilities, 1812)