Hobbes ' geometrical disputes are significant since they highlight several important strands in his thought - issues concerning the right to make definitions, his anti-clericalism, the maker's knowledge argument and his objections to algebra. These are examined, and the foundational position, according to Hobbes, of geomentry in relation to philosophy, science and technology, explained and discussed.

Hobbes on Demonstration and Construction DAVID GAUTHIER 1~ IN 1656 Hobbes published Six Lessons to the Professors of Mathematics, with an Epistle Dedicatory to the Marquis of Dorchester, Lord Pierrepont. In this Epistle, Hobbes distinguishes the demonstrable from the indemonstrable arts: "demonstrable are those the construction of the subject whereof is in the power of the artist himself, who, in his demonstration, does no more but deduce the consequences of his own operation" . Although this passage, with the explication Hobbes (...) offers for it and the consequences he draws from it, and a similar discussion in De homine, published two years later, have not been unnoticed, their significance for Hobbes's account of science in general, and civil philosophy or politics in particular, has not, I think, been I am grateful to the University of East Anglia for appointing me a Visiting Research Fellow during the period in which the first draft of this paper was written. A second draft was presented at the Third Quadrennial International Fellows Conference of the Center for Philosophy of Science at the University of Pittsburgh, sponsored by the Florence Center for the History and Philosophy of Science. I am grateful for the remarks of my commentator, J. E. McGuire, and for the discussion. I am also grateful for the comments of the two referees who read this paper for the Journal of the History of Philosophy. References to Hobbes's works appear as.. (shrink)