At first glance, the formulation of the principle of inertia—not. yet complete with Galileo, more precise with Gassendi, finally systematic with Newton—seems to constitute but one of the aspects of a process of deep transformations at the end of which traditional cosmology was replaced by various world systems. These transformations—or, to use a more classic term, this “ scientific revolution” —have been the object of numerous works, a list, of which would alone fill the pages of a thick volume. But the principle of inertia itself, a principle about which can be said without exaggeration that it expressed the essence of this revolution at the same time as it stimulated it, has perhaps not received all the attention it deserves. And especially the impact of this principle on Western culture has not been fully measured. True, Alexandre Koyré has always insisted on the fact that, by reducing movement to a state like that of the state of rest, the principle of inertia expressed a new vision of the world more than a scientific result. But his admirable analyses deal more with the slow advent of the priciple of inertia among the natural philosophers who preceded, accompanied and then followed Galileo than with the theological, philosophical and literary impact of this principle. Moreover, by examining this impact, we discover that it is necessary to make a distinction between Euclidian space and absolute space, a distinction which is frequently implicit with certain scientific historians, but, and this must be emphasized, is more often ignored.