Barometric pressure was a novel idea in 1647 when the 24-year-old Blaise Pascal published his Nouvelles expériences sur le vide. Toricelli had invented the barometer only four years earlier. Pascal described how he climbed first a tower in Paris and then a mountain in the Auvergne carrying this new instrument, and watched as the column of quicksilver slowly dropped. He deduced that a vacuum must exist above the atmosphere – and thus, in a sense, became the discoverer of outer space.
Pascal recognized – and struggled against – the inadequacy of knowledge to ever encompass the universe. Though the logic of infinity could not be denied, he thought, its existence depressed him. This more than anything testifies to his greatness as a thinker: he was brave enough admit the existence of truths that caused him profound discomfort. While, on the one hand, “It is the heart that perceives God and not the reason,” reason still exerts a critical check on human pride: “Man is equally incapable of seeing the nothingness from which he emerges and the infinity in which he is engulfed.”
Late in life, battling illness, Pascal made a study of the cycloid, a curve traced by a point on the circumference of a hoop traveling along a straight line. Using the “method of indivisibles” pioneered by Cavalieri, Pascal managed to solve a series of problems that had defeated Galileo and Descartes. In the process, he came within a hair’s breadth of discovering the infinitesimal calculus, decades before Leibnitz and Newton. Unable to sleep for pain, he stared up into the darkness and saw the solutions unfold.
Blaise Pascal was a slight man with a booming voice, and people found him pugnacious, even overbearing. Ill health and crushing headaches were his constant companions since childhood. He died of a malignant growth in his stomach that spread to his other organs. A post-mortem examination also revealed an ugly lesion on the brain – the source of his migraines. Apparently, as an infant his fontanelle had failed to close properly, and the bones in his skull had slipped and ground against each other like the tectonic plates that make up the surface of the earth. He died in great agony and convulsions on August 19, 1662, at the age of 39.