An elementary presentation is given of classical and relativistic collision dynamics based upon the principle of conservation of momentum. The concepts of mass are shown to be implicitly defined and their basic properties are rigorously derived and discussed. Luxons and tachyons are treated on the same footing as material particles.

This article has been translated into English by Nancy Luxon and published with permission. Michel Foucault, La littérature et la folie [La folie dans le théâtre baroque et le théâtre d'Artaud], in Folie, langage, littéature, eds. H.-P. Fruchaud, D. Lorenzini, & J. Revel, pp. 89–109 © Librairie philosophique J. Vrin, Paris, 2019. www.vrin.fr Requests for re-use of La littéature et la folie [La folie dans le théâtre baroque et le théâtre d'Artaud] should be directed to Librairie philosophique J. Vrin, (...) Paris. Literature and madness dominate Michel Foucault’s early writings in the 1960s, and indeed much of his career. In this text, Foucault considers the relation between madness, language, and silence; the difficult frontier between language and literary convention; and the experience of madness within language. He moves from a meditation on madness, to a rare commentary on theatre, stagecraft, and Artaud, and finishes by considering literature’s capacity for rupture. ‘Literature and Madness’ is a translation of a text written by Foucault in the 1960s, and recently published in Folie, langage, littérature, ed. Henri-Paul Fruchaud, Daniele Lorenzini and Judith Revel (Paris: Vrin, 2019, 89–109). This version includes a translator’s introduction by Nancy Luxon and was given a distinct subtitle to distinguish it from a similar lecture with the same title in that volume. (shrink)