Throughout his short life, he had never enjoyed long periods of good health; he died on 19 August 1662 after a protracted and painful illness, and his final days were marked by his own deep piety and his desire to fulfil his religious duties to the last.
4 Works posthumously published
Although Pascal was well known to the European scientific community in his lifetime, few of his works were published. His last foray into the world of mathematics – the solution to a set of problems concerning the nature of the cycloid – was in fact circulated anonymously as a competition in 1658, although its author was sufficiently well-known for the Dutch mathematician and physicist Christiaan Huyghens (1629-95) to write to Pascal about it in the following year. After Pascal’s death some mathematicians (including Leibniz) had access to his scientific papers, but these did not all appear in print until much later.
Pascal’s religious writings, however, were posthumously edited by his family and friends; the Pensées and other short works appeared in 1670, and the Entretien avec M. de Saci in 1728. The original edition of the Pensées was both an abridgment and a reworking of Pascal’s papers, only part of which had been put in order by him; since the mid-nineteenth century various attempts have been made to reconstruct the manuscript as it was left by Pascal, culminating in Louis Lafuma’s edition of 1952 which is now taken to be standard. More recently still Pol Ernst has been able not only to reconstruct the pages which were cut up by Pascal himself when he decided to arrange the fragments into thematic groups, but also to establish the date of composition of the major part of the project (1656-8). This recent scholarship has permitted a (somewhat conjectural) chronological ordering of the Pensées to be published and has opened up new possibilities for their interpretation.
5 Mathematical philosophy
Pascal himself said in a letter to Pierre Fermat written in 1660 that he felt that his religious writings had little connection with his scientific and mathematical work. His outlook, however, was deeply influenced by what he conceived to be a new way of looking at the world inspired by geometry, and most commentators would agree that all his writings are impregnated with it. He himself made strictly mathematical contributions to number theory, geometry and probability theory, but he also involved himself in the wider polemic about the status of science in his day.
In his letter to Father Noel, he set out the prerequisites of sound scientific methodology, laid down the rules for making affirmative or negative scientific judgments (through axioms and apodictic demonstration), and for establishing or disproving hypotheses about the physical world, which in his view could never be more than provisional. In the same letter, Pascal referred to the rival claims of authority (in this case, the authority of Aristotle) and scientific demonstration; this topic is more fully developed in the Préface sur le traité du vide (Preface to a treatise on the vacuum) (1651?), in which Pascal shows that experiment and correct reasoning should govern the sciences, and that authority and historical example have no place in them.
His view of science is very much a progressive one; as more and more experiments are undertaken with more sophisticated instruments, previously accepted hypotheses are supplanted by newer ones. Thus the hypothesis of occult qualities or powers, which was postulated to explain what lies beyond sensory perception, and the Aristotelian distinction between act and potency, should be replaced if experimentation can show that they are inadequate according to Pascal’s rules. Natural causation and phenomena are unchanging; human attempts to understand them are relative to the historical moment at which the attempts are made. In a striking image, Pascal refers to the successive generations of scientists as a single person in a perpetual state of existence and development. Thus, when we disagree with scientists of the past, we are not contradicting them, since by applying the principle of charity we would have to agree that we would have understood the world in their way had we lived in their times with their resources; and it follows also that they would have agreed with us today for the same reasons. …
