The History of Continua
Mathematical and philosophical thought about continuity has changed considerably over the ages. Aristotle insisted that continuous substances are not composed of points, and that they can only be divided into parts potentially; a continuum is a unified whole. The most dominant account today, traced to Cantor and Dedekind, is in stark contrast with this, taking a continuum to be composed of infinitely many points. The opening chapters cover the ancient and medieval worlds: the pre-Socratics, Plato, Aristotle, Alexander, and a recently discovered manuscript by Bradwardine. In the early modern period, mathematicians developed the calculus the rise of infinitesimal techniques, thus transforming the notion of continuity. The main figures treated here include Galileo, Cavalieri, Leibniz, and Kant. In the early party of the nineteenth century, Bolzano was one of the first important mathematicians and philosophers to insist that continua are composed of points, and he made a heroic attempt to come to grips with the underlying issues concerning the infinite. The two figures most responsible for the contemporary hegemony concerning continuity are Cantor and Dedekind. Each is treated, along with precursors and influences in both mathematics and philosophy. The next chapters provide analyses of figures like du Bois-Reymond, Weyl, Brouwer, Peirce, and Whitehead. The final four chapters each focus on a more or less contemporary take on continuity that is outside the Dedekind–Cantor hegemony: a predicative approach, accounts that do not take continua to be composed of points, constructive approaches, and non-Archimedean accounts that make essential use of infinitesimals.