See main: Einstein-Pascal dialogue on purpose

“I know not who put me into the world, nor what the world is, nor what I myself am. I am in terrible ignorance of everything. I know not what my body is, nor my senses, nor my soul, not ever that part of me which thinks what I say, which reflects on all and on itself, and knows itself no more than the rest. I see those frightful spaces of the universe which surround me, and I find myself tied to one corner of this vast expanse, without knowing why I am put in this place rather than another, nor why this short time which is given me to live is assigned to me at this point rather than at another of the whole eternity which was before me or which shall come after me. I see nothing but infinities on all sides, which surround me as an atom, and as a shadow which endures only for an instant and returns no more. All I know is that I must die, but what I know least is this very death which I cannot escape.”

A depiction of Pascal's 1648 atmospheric pressure experiment, wherein he had his brother-in-law Florin Perier carry a Torricelli barometer to the top of Puy de Dome, France, to see if the height of the mercury column would fall as a result of decreasing atmospheric pressure, as he predicted.

See main: Pascal atmospheric pressure experiment

“I have thought of an experiment which will remove all doubt, if it be executed with exactness. The experiment should be made in vacuo several times, in one day, with the same quicksilver, at the bottom and at the top of the mountain of Puy, which is near our town of Clermont. If, as I anticipate, the height of the quicksilver be less at top than at the base, it will follow that the weight or pressure of the air is the cause of this; there certainly is more air to press at the foot of the mountain than at its summit, while one cannot say that nature abhors a vacuum in one place more than in another.”

— Blaise Pascal (1648), “Letter to Florin Perier” (Ѻ)

“At eight o'clock, we met in the gardens of the Minim Fathers, which has the lowest elevation in town. First, I poured 16 pounds of quicksilver into a vessel, then took several glass tubes, each four feet long and hermetically sealed at one end and opened at the other. Then placed them in the vessel of quicksilver. I found the quicksilver stood at 26" and 3​1⁄2 lines above the quicksilver in the vessel. I repeated the experiment two more times while standing in the same spot. They produced the same result each time. Taking the other tube and a portion of the quicksilver, I walked to the top of Puy-de-Dôme, about 500 fathoms higher than the monastery, where upon experiment, and found that the quicksilver reached a height of only 23" and 2 lines. I repeated the experiment five times with care. Each at different points on the summit, found the same height of quicksilver, in each case.”

A depiction of one of Blaise Pascal's vacuum experiments, using a water column, in the city of Rouen, France. [7]

See main: Pascal’s wager; See also: Neumann on soul (Ѻ)

“Either god is or he is not. But to which view shall we be inclined? Reason cannot decide this question. Infinite chaos separates us. At the far end of this infinite distance a coin is being spun which will come down heads or tails. How will you wager? Reason cannot make you choose either, reason cannot prove either wrong.”

“You have two things to lose: the true and the good; and two things to stake: your reason and your will, your knowledge and your happiness. Since you must necessarily choose, your reason is no more affronted by choosing one rather than the other. But your happiness? Let us weigh up the gain and the loss involved in calling heads that god exists. Let us assess the two cases: if you win you win everything, if you lose you lose nothing. Do not hesitate then; wager that he does exist.”

“Pascal also performed a void within a void experiment (Ѻ)(Ѻ) . A Torricellian tube was placed within the empty space above the mercury column of a second tube. In the ‘inner barometer’ the level of the mercury in the tube was equal to the level in the bath. In the absence of air, the mercury column was not sustained, and thus it seemed clear that the pressure of the surrounding air was the cause of the elevation of the mercury in Torricelli's experiment. The plenists, however, were not convinced. The experiment could well be explained by a ‘restricted horror vacui’. Moreover, they considered air to be a light element, and thus the explanation using the pressure or weight of air, according to the plenists, was absurd.”

— Anne Helden (1991), “The Age of the Air-Pump” (pg. 151) [8]

“Most of the evils of the world arise from man’s inability to sit still in a room.”

— Blaise Pascal (c.1640), Source; cited by Walter Bagehot (c.1872); cited by Lawrence Henderson in “Sociology 23” [4]

“I have examine if this god, of whom all the world speak, might not have left some marks of himself. I look everywhere, and everywhere I see nothing but obscurity. Nature offers me nothing, that may not be a matter of doubt and inquietude. If I saw nothing in nature which indicated a divinity, I should determine with myself to believe nothing about it. If I everywhere saw the sign of a creator, I should repose myself in peace, in the belief of one. But seeing too much to deny, and too little to assure me of his existence, I am in a situation that I lament, and in which I have a hundred times wished, that if a god does sustain nature, he would give unequivocal marks of it, and that if the signs which he has given be deceitful, that he would suppress them entirely: that he said all or nothing, to the end that I might see which side I ought to follow.”

— Blaise Pascal (c.1650), Thoughts (§8); cited by Baron d’Holbach (1770) in The System of Nature (pg. 306)

“The last thing one discovers in writing a book is what to put first.”

— Blaise Pascal (c.1650)

“Cleopatra's nose, had it been shorter, the whole face of the world would have been changed.”

— Blaise Pascal (c.1650), Pensees (pg. 180) (Ѻ) [3]