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Home > Dictionary of Science Quotations > Scientist Names Index P > Blaise Pascal Quotes > Reason

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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 Quotes on Reason (12 quotes)

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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.
We are generally more effectually persuaded by reasons we have ourselves discovered than by those which have occurred to others.
— Blaise Pascal
Pensées (1670), Section 1, aphorism 18. In H. F. Stewart (ed.), Pascal's Pensées (1950), 11. Original French text in Pensées de Pascal: publiées dans leur texte authentique (1866), Vol. 1, 99.
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~~[Orphan ?]~~ Reason is the slow and tortuous method by which those who do not know the truth discover it.
— Blaise Pascal
Webmaster presently believes this is an orphan quote, best attributed to Anonymous. It seem to be unsupported when attributed to Blaise Pascal, for example, as quoted, without citation, in Morris Kline, 'Ancients versus Moderns, A New Battle of the Books', The Mathematics Teacher (Oct 1958), 51, No. 6, 423. Also later published, without citation, in Morris Kline, Mathematical Thought From Ancient to Modern Times (1972), 296. Webmaster has not yet found a primary source for this as a quote by Pascal - not in English, not in French, and not in any earlier books. This is suspicious. (Can you help?) Furthermore, this sentence is also often seen in more recent books and online quotes pages as a first sentence, followed by a second sentence, “The heart has its reasons, which reason does not know.” The second sentence is a known Pascal quote verified in original French texts. However, Webmaster has not yet found, in any original French text, any instance of these two sentences together. Thus, putting them together more definitely appears to be a misquote. Can you help? [It is included on the Blaise Pascal page to link it with this cautionary note. —Webmaster]
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A game is on, at the other end of this infinite distance, and heads or tails will turn up. What will you wager? According to reason you cannot leave either; according to reason you cannot leave either undone... Yes, but wager you must; there is no option, you have embarked on it. So which will you have. Come. Since you must choose, let us see what concerns you least. You have two things to lose: truth and good, and two things to stake: your reason and your will, your knowledge and your happiness. And your nature has two things to shun: error and misery. Your reason does not suffer by your choosing one more than the other, for you must choose. That is one point cleared. But your happiness? Let us weigh gain and loss in calling heads that God is. Reckon these two chances: if you win, you win all; if you lose, you lose naught. Then do not hesitate, wager that He is.
— Blaise Pascal
Pensées (1670), Section I, aphorism 223. In H. F. Stewart (ed.), Pascal's Pensées (1950), 117-119.
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Every gambler stakes a certainty to gain an uncertainty, and yet he stakes a finite certainty against a finite uncertainty without acting unreasonably. … The uncertainty of gain is proportioned to the certainty of the stake, according to the proportion of chances of gain and loss, and if therefore there are as many chances on one side as on the other, the game is even.
— Blaise Pascal
In Blaise Pascal and C. Kegan Paul (trans.), 'Of The Need of Seeking Truth', The Thought of Blaise Pascal: Translated from the Text of M. Auguste Molinier (1905), 98.
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It is the heart which experiences God, and not the reason.
— Blaise Pascal
In Pensées (1670), Section 26, No. 5. From Blaise Pascal, W.F. Trotter (trans.), 'Thoughts', collected in Charles W. Eliot (ed.), The Harvard Classics (1910), Vol. 48, 99. Also seen translated as, “It is the heart which perceives God, and not the reason”. From the French, “C'est le cœur qui sent Dieu, et non la raison,” in Ernest Havet (ed.),Pensées de Pascal (1852), 296.
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Logic has borrowed the rules of geometry without understanding its power. … I am far from placing logicians by the side of geometers who teach the true way to guide the reason. … The method of avoiding error is sought by every one. The logicians profess to lead the way, the geometers alone reach it, and aside from their science there is no true demonstration.
— Blaise Pascal
From De l’Art de Persuader, (1657). Pensées de Pascal (1842), Part 1, Article 3, 41-42. As translated in Robert Édouard Moritz, Memorabilia Mathematica; Or, The Philomath’s Quotation-Book (1914), 202. From the original French, “La logique a peut-être emprunté les règles de la géométrie sans en comprendre la force … je serai bien éloigné de les mettre en parallèle avec les géomètres, qui apprennent la véritable méthode de conduire la raison. … La méthode de ne point errer est recherchée de tout le monde. Les logiciens font profession d'y conduire, les géomètres seuls y arrivent; et, hors de leur science …, il n'y a point de véritables démonstrations ….”
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The heart has its reasons which reason does not know.
— Blaise Pascal
In Pensées (1670). As translated in Blaise Pascal and W.F. Trotter (trans.), 'Thoughts', collected in Charles W. Eliot (ed.), The Harvard Classics (1910), Vol. 48, 99. From the original French, “Le cœur a ses raisons, que la raison ne connaît point,” in Blaise Pascal and Armand-Prosper Faugère (ed.), Pensées, Fragments et Lettres de Blaise Pascal (1814), Vol. 2, 172.
Science quotes on:  |  Heart (243)  |  Know (1538)  |  Reason (766)

The last proceeding of reason is to recognize that there an infinity of things which are beyond it.
— Blaise Pascal
Pensées (1670), Section 5, 1. As translated in Blaise Pascal and W.F. Trotter (trans.), 'Thoughts', No. 267, collected in Charles W. Eliot (ed.), The Harvard Classics (1910), Vol. 48, 97. Also seen translated as, “Reason’s last step is the recognition that…”. From the original French, “La dernière démarche de la raison est de reconnaître qu’il y a une infinité de choses qui la surpassent; elle n’est que faible, si elle ne va jusqu’à connaître cela,” in Pensées de Blaise Pascal (1847), 110.
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Those who are accustomed to judge by feeling do not understand the process of reasoning, because they want to comprehend at a glance and are not used to seeking for first principles. Those, on the other hand, who are accustomed to reason from first principles do not understand matters of feeling at all, because they look for first principles and are unable to comprehend at a glance.
— Blaise Pascal
In Pensées (1670), Section 7, No. 33. As translated in W.H. Auden and L. Kronenberger (eds.) The Viking Book of Aphorisms (1966), 351. Also translated as “Those who are accustomed to judge by feeling do not understand the process of reasoning, for they would understand at first sight, and are not used to seek for principles. And others, on the contrary, who are accustomed to reason from principles, do not at all understand matters of feeling, seeking principles, and being unable to see at a glance,” in Blaise Pascal and W.F. Trotter (trans.), 'Thoughts', No. 3, collected in Charles W. Eliot (ed.), The Harvard Classics (1910), Vol. 48, 9. From the original French, “Ceux qui sont accoutumés à juger par le sentiment ne comprennent rien aux choses de raisonnement, car ils veulent d’abord pénétrer d’une vue et ne sont point accoutumés à chercher les principes. Et les autres, au contraire, qui sont accoutumés à raisonner par principes, ne comprennent rien aux choses de sentiment, y cherchant des principes et ne pouvant voir d’une vue,” in Ernest Havet (ed.), Pensées de Pascal (1892), 224.
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We know the truth not only through our reason but also through our heart. It is through the latter that we know first principles, and reason, which has nothing to do with it, tries in vain to refute them.
— Blaise Pascal
Pensées (1670), trans. A.J. Krailsheimer (1966), Section 1, VI, aphorism 110, 58.
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We know truth, not only by the reason, but also by the heart.
— Blaise Pascal
In Pensées (1670), Section 8, No. 6. As translated in Blaise Pascal and W.F. Trotter (trans.), 'Thoughts', No. 282, collected in Charles W. Eliot (ed.), The Harvard Classics (1910), Vol. 48, 99. Translated as “We arrive at truth, not by reason only, but also by the heart,” in W.H. Auden and L. Kronenberger (eds.) The Viking Book of Aphorisms (1966). From the original French, “Nous connaissons la vérité, non seulement par la raison, mais encore par le cœur,” in Ernest Havet (ed.), Pensées de Pascal (1892), 238.
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You see, if the height of the mercury [barometer] column is less on the top of a mountain than at the foot of it (as I have many reasons for believing, although everyone who has so far written about it is of the contrary opinion), it follows that the weight of the air must be the sole cause of the phenomenon, and not that abhorrence of a vacuum, since it is obvious that at the foot of the mountain there is more air to have weight than at the summit, and we cannot possibly say that the air at the foot of the mountain has a greater aversion to empty space than at the top.
— Blaise Pascal
In letter to brother-in-law Perier (Nov 1647) as given in Daniel Webster Hering, Physics: the Science of the Forces of Nature (1922), 114. As also stated by Hering, Perier conducted an experiment on 19 Sep 1648 comparing readings on two barometers, one at the foot, and another at the top of 4,000-ft Puy-de-Dôme neighboring mountain.
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See also:
  • 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 “Reasons we have ourselves discovered” - Large image (800 x 400 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)

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