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Thumbnail of Blaise Pascal (source)
Blaise Pascal
(19 Jun 1623 - 19 Aug 1662)

French mathematician and physicist who was a child prodigy. In mathematics, he developed a theory of probabilities. In physics, he invented the hydraulic press and formulated Pascal’s Law for pressure.

Blaise Pascal
“Reasons we have ourselves discovered”

Illustrated Quote - Large (800 x 400 px)

“We are generally more effectually persuaded by reasons we have ourselves discovered than by those which have occurred to others.”
— Blaise Pascal
Pensées (1670).

More Blaise Pascal quotes on science >>

When Blaise Pascal died, at the young at of 39, he left hundreds of his first notes for a largely unfinished text—as in Sainte-Beuve's words, a tower of which the stones have been laid on each other, but not cemented, and the structure unfinished.1 If completed, his book was to have been a a defense of Christianity. The fragments were published eight years later, in 1670, as Pensées (Thoughts). They demonstrate his genius including not only the science for which he is remembered, but also they had the nature of a psychologist and a moralist.

Additional science-related Pensées can be read on the quotation page for Blaise Pascal on this site, as listed in the links below.

The subject quote is one variation of translated versions of the original, which was written in French:

On se persuade mieux, pour l’ordinaire, par les raisons qu’on a soi-même trouvées, que par celles qui sont venues dans l’esprit des autres.

A similar idea2 was expressed by Joseph Joubert (1754-1824) in his collection of Pensées (also published posthumously, in 1838):

On peut convainere les autres par ses propres raisons, mais on ne les persuade que par les leurs.

We may convince others by our arguments, but we can only persuade them by their own.

1 From Introduction by T.S. Eliot to Pascal’s Pensées (1958), xi.
2 Footnoted by Ernest Havet in Pensées de Pascal: publiées dans leur texte authentique (1866), Vol. 1, 99.

Text by Webmaster with quote from Pensées (1670), as translated into English by Alban John Krailsheimer (1966), Section 1, VI, aphorism 110, 58. For original French quotes see Footnote 2. (source)

See also:
  • Science Quotes by Blaise Pascal.
  • 19 Jun - short biography, births, deaths and events on date of Pascal's birth.
  • Blaise Pascal - context of quote “Flies are so mighty” - Medium image (500 x 250 px)
  • Blaise Pascal - context of quote “Flies are so mighty” - Large image (800 x 400 px)
  • Blaise Pascal - context of quote “Reasons we have ourselves discovered” - Medium image (500 x 250 px)
  • Blaise Pascal - context of quote “Knowledge of morality” - Medium image (500 x 250 px)
  • Blaise Pascal - context of quote “Knowledge of morality” - Large image (800 x 400 px)

Nature bears long with those who wrong her. She is patient under abuse. But when abuse has gone too far, when the time of reckoning finally comes, she is equally slow to be appeased and to turn away her wrath. (1882) -- Nathaniel Egleston, who was writing then about deforestation, but speaks equally well about the danger of climate change today.
Carl Sagan Thumbnail Carl Sagan: In science it often happens that scientists say, 'You know that's a really good argument; my position is mistaken,' and then they would actually change their minds and you never hear that old view from them again. They really do it. It doesn't happen as often as it should, because scientists are human and change is sometimes painful. But it happens every day. I cannot recall the last time something like that happened in politics or religion. (1987) ...(more by Sagan)

Albert Einstein: I used to wonder how it comes about that the electron is negative. Negative-positive—these are perfectly symmetric in physics. There is no reason whatever to prefer one to the other. Then why is the electron negative? I thought about this for a long time and at last all I could think was “It won the fight!” ...(more by Einstein)

Richard Feynman: It is the facts that matter, not the proofs. Physics can progress without the proofs, but we can't go on without the facts ... if the facts are right, then the proofs are a matter of playing around with the algebra correctly. ...(more by Feynman)
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