Blaise Pascal, then a young man, and father Etienne Noel, a Jesuit, held very different views on the notion of the vacuum in physics. They thus started a controversy fuelled by letters which circulated between October 1647 and the summer 1648. This scientific polemic has only been partially analysed. The historians of sciences often consider it as a case in point illustrating the fight between old-fashioned aristotelism (gilded with a touch of cartesianism) and the budding modern experimental science. The letters exchanged between Pascal and Noel are commonly used to show that Pascal was already purging physics from its literary, theological and philosophical basis in order to turn it into an autonomous, self-relying subject matter of discourse. With its use of irony this polemic against a single Jesuit is often considered as a warning which paves the way for the broader attack on the Jesuit institution that the Provinciales constitute. Instead of reading this controversy with the Jesuit defeat in mind, this article seeks on the contrary to read it in its own scientific context . This was a time of deep scholarly interest for the new scientific discoveries. It was also the moment when Father Mersenne was the arbiter of all European controversies. In this context, Father Noel was a respected and well-known scholar whose opinions were sought after by many, including Descartes. His conception of the vacuum was therefore highly representative of what many scientists believed. Moreover the question of the vacuum also triggered some more substantial questions than mere technical problems of experimentation. Noel himself chose to discuss that baroque theme in an aristotelian fashion. For him, the vacuum could not be found in nature because its substance could not without a miracle be separated from the accident, and remain intact. The present study shows that Pascal did not attack a second-rate scientist. The arguments of both parties also proved that it was no easy victory for Pascal.