Truly man is a marvelously vain, diverse, and undulating object. It is hard to found any constant and uniform judgment on him. Michel de Montaigne, Les Essais, Book I, Chapter 1: "By diverse means we arrive at the same end"; in The Complete Essays of Montaigne, Donald M. Frame transl., Stanford University Press (1958).Pour distinguer les choses les plus simples de celles qui sont compliquées et pour les chercher avec ordre, il faut, dans chaque série de choses où nous avons déduit directement quelques vérités d'autres vérités, voir quelle est la chose la plus simple, et comment toutes les autres en sont plus, ou moins, ouégalementéloignées. René Descartes, Règles pour la direction de l'esprit, Règle VI.In order to distinguish what is most simple from what is complex, and to deal with things in an orderly way, what we must do, whenever we have a series in which we have directly deduced a number of truths one from another, is to observe which one is most simple, and how far all the others are removed from this-whether more, or less, or equally. René Descartes, Rules for the Direction of the Mind, Rule VI. 1 Expanded and updated version (13 May 2007). 2 Note: From géomance, a way to foretell the future; a form of divination. 202 B. Duplantier Poincaré Seminar 2005 L'antimodernisme, c'est la liberté des modernes. Antoine Compagnon, about his book "Les antimodernes : de Joseph de Maistreà Roland Barthes," Bibliothèque des Idées, Gallimard, March 2005.Antimodernism is the liberty of modern men.Here we briefly describe the history of Brownian motion, as well as the contributions of Einstein, Sutherland, Smoluchowski, Bachelier, Perrin and Langevin to its theory. The always topical importance in physics of the theory of Brownian motion is illustrated by recent biophysical experiments, where it serves, for instance, for the measurement of the pulling force on a single DNA molecule.In the second part, we stress the mathematical importance of the theory of Brownian motion, illustrated by two chosen examples. The by-now classic representation of the Newtonian potential by Brownian motion is explained in an elementary way. We conclude with the description of recent progress seen in the geometry of the planar Brownian curve. At its heart lie the concepts of conformal invariance and multifractality, associated with the potential theory of the Brownian curve itself.
A brief history of Brownian motionSeveral classic works give a historical view of Brownian motion. Amongst them, we cite those of Brush, 3 Nelson, 4 Nye, 5 Pais 6 , Stachel 7 and Wax. 8 We also cite a number of essays in mathematics, 9 physics, 10 11 especially those which have appeared very recently for the centenary of Einstein's 1905 articles, 12 and in biology. 13 3 Stephen G.