Pascal, Blaise (1623–62)
Authors: MacLean Ian 
Published: September 2018

Blaise Pascal was a mathematical prodigy who numbered among his early achievements an essay on conic sections and the invention of a calculating machine. In his early twenties he engaged in the vigorous European debate about the vacuum, undertaking, or causing to be undertaken, a series of experiments which helped to refute the traditional view that nature abhors a vacuum and setting out clearly the methodology of the new science. In 1646 he came under the influence of Jansenism; this he seems to have rejected for a short time in the early 1650s, but he then underwent a profound spiritual experience which transformed his life and drew him into close association with leading Jansenists, with whom he collaborated in producing the polemical Lettres provinciales (1656–7). At the same time he planned to write an apology for the Christian religion, but ill-health so affected his final years that this only survives in the fragmentary form of the Pensées (1670). He made significant contributions to mathematics, especially in the fields of geometry, number theory and probability theory, and he also helped to describe the ’esprit géométrique’ which characterized the new science of the 1650s. He argued that geometry was superior to logic in that it could provide not only demonstrative procedures but also axioms from which to work; and he set down appropriate rules of argument. His religious writings were published shortly after his death; many attempts have been made to reconstruct the apology which they encapsulate. It seems most likely that this would have fallen into two parts, the first setting out the wretchedness of humans without God, the second demonstrating the truth of Christianity and the felicity of the religious life. Humans are portrayed in Augustinian terms as corrupt, vapid creatures, prey to their passions and the delusions of imagination; but they are also shown to possess greatness through their reason and self-awareness, which can bring them to recognize that Christianity alone has represented their predicament accurately, and that they should turn to religion, even if initially they lack the instinctive faith which is the hallmark of the saved. In the ‘wager’ fragment, Pascal employs his mathematical insights to revivify an old apologetic argument (that it is wiser to bet on God existing rather than on his not existing) and to link it to an existential imperative (that we all are obliged to choose between these alternatives). The adroit interplay between scepticism, rationalism and faith of the first part is succeeded by a second part which argues the veracity of Christianity from Biblical interpretation, prophecies and miracles. Pascal concedes that this cannot carry absolute conviction; but he insists that the rejection of such arguments is caused not by man’s rational powers but by his corrupt passions. Pascal’s Pensées are written for the most part in terse aphoristic form; he aspired to a style that was so accessible that the reader would believe he was experiencing as his own the thoughts that he read. Although Pascal said at the end of his life that he considered his mathematical pursuits a quite separate enterprise from his religious writings, a common epistemology can be found in both, together with a scientific outlook which Pascal saw as superior to the philosophical alternatives of his day.