Pascal's Wager Read online

  Then, in the nearby town of Rouville, an evangelical pastor came to town and preached the new piety at all the Masses. The priest’s name was Jean Guillebert, and he came equipped with a shiny new doctorate of theology from the Sorbonne. For years, he had followed the medieval tradition of taking a benefice from the parish without actually doing anything for the people and used the money to support his theological studies. But while at the Sorbonne, he had met the abbé de Saint-Cyran and picked up the new piety from him. From that day on, he became a priest in earnest. He actually moved back to his parish and started caring for the people.

  This was the man who would convert the entire Pascal family. Apparently, his sermons were entertaining enough, for he drew crowds from all over Normandy. According to Gilberte, Guillebert was filled with an admirable piety and preached the finest sermons.

  Now, however, closing the circuit, there were two young men sitting in the congregation in Rouville, taking in every word—two men who happened to be the bonesetters of Rouen, Monsieur Deslandes and Monsieur de La Bouteillerie. And when they arrived for their extended stay at the Pascal house behind the monastery of Saint-Ouen, they were on fire. In the quiet hours, they held long conversations with the family, and if Étienne was not ready to leap from his bed and run off to Rouville, Blaise certainly was. He read Saint-Cyran’s Réformation de l’homme intéri-eur (Reformation of the Interior Man) and was mesmerized. Perhaps he was looking for a spiritual life that was as challenging as his science. In the end, Blaise caught fire along with everyone else.

  Who knows what people see in a belief that moves them? Whatever caused it, something clicked on in Blaise’s psyche, and from that point on his heart went to war with his mind. There was much that troubled Blaise in Saint-Cyran’s book—as much as what excited him. In one passage, he read that Jansen believed that scientific curiosity was nothing more than another kind of sexual indulgence, and this agonized him. Suddenly, the thing that had given Blaise his identity, his greatest joy in a life of pain, had become a wickedness. How could he seek the salvation of his soul under these conditions? How much of himself would he have to give up? Everything, it seemed. A shadow fell on his spirit that would never lift.

  Two strange attractors have emerged repeatedly in the long intellectual history of Catholicism; these two traditions, like gravity wells, have drawn adherents to themselves, becoming fashionable in their turn, white hot for a time, then cooling off like aging stars, only to be replaced by the other tradition. Those who seek to find God in all things, who have a general faith in reason, who believe that the world is a wide and good place and that people are reasonably decent, end up orbiting around the ideas of Thomas Aquinas (ideas known collectively as Thomism) and his Christian reclamation of Aristotle. Those who seek to find God outside human experiences, who distrust reason, who think that the world is a shipwreck and that people are no damn good, usually orbit around the ideas of Augustine. The more positive Thomism had no problem with Christians engaging in scientific study. Aquinas himself wrote his Summa theologiae in order to show that Christianity was not antirational, as opposed to the more advanced Aristotelian science of Islam. Perhaps it was a sign of the times, or perhaps it was an indicator of the younger Pascal’s quirky personality; in any case, he chose the one Catholic theological tradition most likely to set the two most important parts of his life into combat.

  Blaise was then twenty-four years old. He was beyond the age at which a man strikes out on his own, but in the Pascal family such an action was unthinkable. Old Étienne had a plan for everyone, especially his only son. By that time, Blaise had done everything his father had expected of him; he had achieved preeminence in the scientific world that few had ever attained. His work on conic sections; his arithmetic machine, the Pascaline; and his experiments on the vacuum—these had made him famous. And thanks to Marin Mersenne, Blaise’s name was known to the best minds in Europe. But all of this was according to his father’s plan. What part of his life was Blaise’s own? What part of himself was his? It was tragic that at this precise moment in his life, while seeking the truth of his soul, while brawling through that exquisite moment of vulnerability that young men wrap themselves in like a battle flag, he came upon the ideas of Cornelis Jansen and the abbé de Saint-Cyran.

  Blaise continued his pious reading and from there plunged into works of theology, ever deeper into the writings of Jansen, Saint-Cyran, and Antoine Arnauld, who had become their great apologist, and bit by bit his conversion took hold. As Blaise was caught in his spiritual reading, he fretted about his life. He began to wonder if what he had been doing, his best accomplishments, was an act of supreme narcissism and a kind of attachment to the world. He had spent his entire young life spinning out variations on the strictest form of mathematical reasoning, and yet this very reasoning was now suspect. Mathematics was the most precise of the sciences and the one antidote Christian thinkers had in their arsenal to fight the skepticism that was rising like a fume from the libertins érudits. The seventeenth century was becoming an age of suspicion, because many of the old forms of reason were dying, and many thoughtful people, instead of trying to build up something new, wanted to tear everything down.

  Then there were those, led by Descartes, who were casting about for something radically new to fill the gap. How could they build a new metaphysics that possessed both the certainty of mathematics and the scope of Aristotle? This was the question that Descartes was sure he had solved with his new method, one that cleverly wove in the very skepticism of the new thinkers and yet arrived at a new and more certain metaphysics for a new age. But even these attempts to shore up the dike of reason were being called into question.

  Blaise, however, embraced the skepticism by acknowledging that human science, for all its power, was deeply flawed. He rejected Thomism and accepted Augustinian pessimism about human reason, perhaps because he was all too aware of the destructive power of sin. His whole life could be explained by that power. Sin and pain accounted for much of his story: his childhood disease, his mother’s death, his father’s flight from Paris, the terrible peasant uprisings he saw all around him in Normandy, the poverty, and the disease. Had Adam not sinned, none of these things would have happened. When sin entered the world, it brought death along for the ride and, with death, disease. Here, perhaps, was a more satisfying explanation for the realities of the world than mathematics.

  Much later, in his Pensées, he placed humankind on an open field between the angels and the animals, noble and wretched at the same time. Wretchedness was the product of sin and was constitutional, a part of human nature, whereas reason, also constitutional, was the product of God’s grace. But reason could plumb reality only so far, whereas wretchedness sank clear to the bone. The only way to understand the deep truths of life would be through the reasons of the heart, and not the reasons of the mind. We must make use of the nonrational parts of ourselves if we truly wish to understand. A mathematician he remained, but he never trusted mathematics the way Descartes did. In those three months, Blaise Pascal set himself on a course that would make him the great syncopation to the coming modern age, and for all his personal suffering, his writings lent depth and grace to the coming centuries. Years after his death, his ideas haunted the great minds—Voltaire especially, who despised Pascal’s trenchant Catholicism and yet could not deny the brilliance of his mind and the sweetness of his French.

  And so, Blaise was converted, at least for the time being. His faith would wax and wane over the years. First, with the help of the bonesetters, he set to work on Jacqueline, whose faith would not wax and wane, and then the two of them set to work on Gilberte. Étienne remained skeptical, but slowly drifted in their direction. What was he to do? His children were his life, and whether he wanted them to or not, they had struck out on their own. All his adult life, he had been leading them; now they were leading him.

  Still, Blaise was not entirely converted, not quite ready to give up his science. He had devoted too much of hi
mself to it to do that. That would have to come a few years later, after the death of his father and after the night his heart was seared by divine fire.

  [1647] January and February

  The Showman

  The show must go on,

  The show must go on

  Inside my heart is breaking

  My make-up may be flaking

  But my smile still stays on.

  —QUEEN, “THE SHOW MUST GO ON”

  Live to be the show and gaze o’ the time.

  —SHAKESPEARE, Macbeth

  Science in the seventeenth century was a serious business, but it was also entertainment. Any serious researcher, if he found something of value, would sooner or later have to make a public demonstration of his experiment, either in front of the king or before a collection of interested nobility, or in a public square where the audiences alternately grumbled and were amazed. A scientist paved his reputation with such stones, because public demonstrations often led to wider controversies and therefore to larger audiences. This had a downside, however. One of the reasons Galileo had such a difficult time with the Inquisition was that he published his dialogues for a general audience and not for the hothouse world of scholars, where his ideas might generate some heat, but not enough to explode. There is always a whiff of sedition when new ideas go public. With the lessons of the Reformation firmly in mind, the hierarchy of the Catholic Church naturally wanted to keep a watch on things, to make sure that nothing radical crept past them.

  In January and February of 1647, while his father was yet healing from his broken hip, Pascal spent a great deal of money staging a series of big demonstrations of the vacuum in an open square in front of a glass factory. He had ordered a number of long glass tubes, of various lengths, up to forty-five feet long, and bound the longer ones to a ship’s mast. Then, after filling them with different kinds of liquid, he used a contraption made of ropes and pulleys to rotate the mast and inserted the bottoms of the tubes in basins of liquid. In each case, an empty space, apparently a vacuum, opened at the top of the tube as the liquid fell, but not all the way. People applauded, astounded by what they saw.

  In a sense, Pascal was reworking old ground by returning to experiments done by Gasparo Berti before Torricelli made his discoveries with mercury, but for the people of Rouen it was all new. As with Galileo, the local Aristotelians buzzed with outrage. Jacques Pierius, from the University of Rouen, dashed off a pamphlet—Can a Void Exist in Nature? Air must have gotten into the gap at the top of the liquid, he said, air or some even more rarefied gas, unnamed spirits that filled the apparently empty space. Pascal, goaded by their resistance, invited any and all who were interested to come to the glassworks once again for a more dramatic demonstration. On the day, spectators collected in the yard before the mast with two forty-foot glass tubes of liquid tied to it, one full of water and the other full of wine. Naturally, the column of water would fall farther than the column of wine, since water is denser than wine, something that Pascal already knew but the spectators did not. What’s more, Pascal had already calculated the difference, and, like any good magician, he prepared his audience to be amazed.

  Before rotating the mast with the two glass tubes, he staged a question period with them, asking if wine contained more spirits than water. The audience nodded, looking at one another, uncertain; a few shouted yes, of course it does. Then, Pascal said to them, once the mast is rotated, shouldn’t they see a greater space above the wine than above the water? After all, the increased spirits in wine should push it down farther than the water. They agreed to that as well. Then Pascal rotated the mast, but the water fell farther than the wine, in spite of the spirits. The crowd was stunned to silence. A few grumbled that it was a trick. Pascal, not satisfied with their silence, went on: he exchanged the two liquids, pouring out the water from one, the wine from the other, and then reversing them. The result was the same. The Aristotelians grumbled louder, and arguments broke out. What spirits? some said. I don’t see any spirits, do you? The Aristotelians said there must be an even more subtle substance inside the glass. How, they argued, thinking of the power of suction, could such a column of liquid be supported by nothing?

  One fellow took the argument to its furthest point by proposing a thought experiment: what if they built a glass flask that was long enough to lie tangent to the earth, a tube that would stretch some 8,856 kilometers, and then stuck the bottom of the flask into a canal? Could that bit of emptiness at the top hold up all that water? At this point, Pascal didn’t know, and he puzzled over it. Eventually, the question sent him down the right path. He began to wonder if the columns of water, rather than being sucked up from the top, were pushed up from below—the same thing Torricelli had realized a few years earlier, though his speculations had not yet arrived in France. So Pascal performed more experiments, and still they grumbled. No one likes a show-off.

  After the demonstration, Pascal carried on a number of public experiments, each with the same general result, each drawing out the same arguments. But these experiments quickly exhausted him, so that after they were done he took to his bed with a migraine and a terrible weakness in his legs. Blaise’s illness had grown worse. He developed a rare form of tuberculosis, and his father sent him back to Paris, where the doctors were better. But someone had to take charge of Blaise’s care. Gilberte had married her cousin Florin Perier, and they had moved back to Clermont in June of 1641. So in order to preserve Blaise’s health, Étienne sent Jacqueline along to care for him.

  Once Blaise arrived in Paris, his friends, especially Marin Mersenne and Gilles Roberval, grew anxious that he publish his findings as soon as possible. They were afraid that someone else would grab the credit if Pascal did not publish, and publish soon. But Blaise was ill throughout much of 1647, and his ability to sit at his desk and churn out copy was limited. Roberval fended off Aristotelian criticism as best he could, while Mersenne told everyone he could that Pascal would publish his work quite soon.

  This galvanized Pascal, sick as he was, to climb out of bed and write up his results. His concern was a matter of ego, of course, but also of scientific honesty. Pascal had taken great care to perform his experiments correctly, and what would happen if someone who had not taken such care were to publish a paper full of quick and dirty findings? Pascal would be weighing in with too little, too late—would have to battle uphill against poor science. In his final product, New Experiments About the Vacuum, dedicated to his father, Blaise described a number of experiments, made with “quicksilver, water, wine, oil, air, etc.,” and explained the significance of each one. His purpose was to prove the existence of the vacuum, but then to “leave it to learned and interested persons to test what happens in such a space.”24

  In the New Experiments, Pascal describes how he took a glass syringe with a “very exact” piston inside of it and then plunged the entire affair into water. When he pulled back the piston, it created a vacuum with very little resistance, in spite of the fact that the Aristotelians had taught that this would require an infinite force. He goes on to describe how he later used a bellows to create the same effect, and then how he took a glass tube, forty-six feet long, full of red wine, and stuck it into a tub of water, removed the plug on the bottom, and observed how the wine poured out and mixed with the water, turning it pink. The wine kept pouring out until the liquid left in the tube had reached a certain level, and then stopped a number of feet higher than the level of the wine-and-water mixture in the tub. And that was the mystery: why would the wine stop falling? Was it sucked from the top, or pushed from the bottom? He re-created Galileo’s experiment by using a piston to suck mercury up through a glass tube, watching it rise until it reached a certain point, and then observing a space open between the top of the mercury and the bottom of the piston. Galileo had interpreted this behavior as owing to the “breaking point” of the liquid rather than to the pressure of the outside air. Pascal then calculated that the eighteen braccia reported by Galileo as the breaki
ng point of water, which Pascal translated as thirty-one feet, would turn out to be two feet, three inches when done with mercury.

  At the end of these experiments, he was fairly certain that the space above the wine, the water, the mercury, or the oil was not filled with air that had somehow gotten in, either through a mistake or through pores in the glass; nor had any air bubbled up from the liquid, nor was the space filled with a subtle vapor, a “spirit,” or whatnot. What he was not certain of was whether the apparent vacuum was a real one, and this was as much a methodological problem as an ontological one. Pascal was not convinced that his experiments had proved the existence of a real, actual void above the glass, only the existence of something that looked and acted like a void. The question remained: what was this empty space?

  Back in Paris, Pascal’s illness nearly overwhelmed him. He suffered from constant migraines, night sweats, and such weakness that he could barely talk. He rarely bathed because this set off the headaches, and so his body stank. Still, he was able to attend church with some assistance, if nothing else. On Sunday, September 22, 1647, two men, a Monsieur Habert and a Monsieur de Montigny, came to visit the Pascal home while Blaise was off at church, and they spoke at length with Jacqueline. Both men were friends of René Descartes, and announced that Monsieur Descartes had “expressed a strong desire” to meet with Blaise and that he had “the greatest respect” for Étienne and his son because of their many accomplishments. They further announced that Descartes wished to pay a visit the next morning at nine o’clock, if it was not inconvenient, given Blaise’s illness. Not knowing what to do, Jacqueline couldn’t find a good reason to turn away the great René Descartes, so she agreed, but asked if they could come a bit later. Her brother suffered most in the early morning, she told them. They agreed to arrive at ten thirty instead.