The history and philosophy of science are destined to play a fundamental role in an epoch marked by a major scientific revolution. This ongoing revolution, principally affecting mathematics and physics, entails a profound upheaval of our conception of space, space–time, and, consequently, of natural laws themselves. Briefly, this revolution can be summarized by the following two trends: by the search for a unified theory of the four fundamental forces of nature, which are known, as of now, as gravity, electromagnetism, and (...) strong and weak nuclear forces; by the search for new mathematical concepts capable of elucidating and therefore explaining such a relationship. In fact, the first search is essentially dependent on the second; that is to say, that in order for a new theory of physics to come to light, the development of a deeper geometric theory capable of explaining the structure of space–time on a quantum scale appears to be necessary. On careful consideration, we notice that both of these developments converge in the direction of a unitary and fundamental tendency of modern science—which is the geometrization of theoretical physics and of natural sciences. This new emergent situation carries within it a profound conceptual change, affecting the way in which relations are conceived of, first and foremost, between mathematics and physics. This new paradigm can be summed up by the intimately interdependent points: the immense variety of physical phenomena and of natural forms follows from the equally infinite variety of geometric and topological objects that can be made out in space and from which space is made up; the second point, which ensues from the former one and which is of great historical and epistemological significance, is that mathematics is involved in rather than applied to phenomena. In other words, phenomena are effects that emerge from the geometrical structure of space–time. There is no doubt that this new conception of the relationship between the universe of mathematical ideas and objects and the world of natural phenomena is the true scientific revolution of our century, of great conceptual importance, and consequently, capable of changing our view of science and of nature at one and the same time. It is all at once of a scientific, philosophical and aesthetic order. (shrink)

Dans sa Catoptrique, Héron d’Alexandrie déduit la loi de la réflexion de la lumière en s’appuyant sur un principe inédit, le principe du plus court chemin. L’article, après avoir retracé les grandes lignes de la démonstration, s’attache à mettre en évidence l’originalité et la fécondité de la méthode utilisée. Le recours à un principe d’extrémalité pour rendre compte des phénomènes lumineux tranche avec l’approche qu’adoptera Ptolémée dans son Optique par exemple, et anticipe par certains côtés l’optique géométrique moderne, dont Héron (...) apparaît comme une sorte de précurseur involontaire. Mais au‑delà de l’aspect purement historique, l’article insiste sur la portée épistémologique majeure du principe héronien, et des principes d’extrémalité en général, qui s’inscrivent dans une tradition scientifique bien précise, et toujours actuelle, celle qui privilégie, au rebours de l’expérimentalisme et de l’instrumentalisme, la causalité finale et formelle dans l’explication des phénomènes et promeut en définitive les mathématiques au rang de principe ontologique fondamental. Dans cette perspective, la démarche suivie dans la Catoptrique révèle non seulement sa profonde modernité, mais pourrait bien apparaître comme une des plus emblématiques qui soient. (shrink)