¹ This touches on a problem too complex to be dealt with satisfactorily here, and is therefore unavoidably oversimplified. Cf. P. Duhem, La théorie physique, Paris, Marcel Rivière & C", 1914, pp. 278-285. Cf. alto Bronowski, J., "Human ism and the Growth of Knowledge," The Philosophy of Karl Popper, ed. Paul A. Schilpp, LaSalle, Ill., Open Court Publishing Co.; 1974, pp. 618-628.

² "And if one wishes to understand the motivations to which the scholar has adhered in analyzing what he has done it will obviously be particularly useful to listen to what arguments he will bring to bear when he has to defend his method of analysis against contestations and attacks. This is exactly what happens during the discussions at scientific congresses - such as the Solvay Congress, for example, whose proceedings, as my readers know, have given us some singularly precious insights." - Emile Meyerson, "Etudes des produits de a pensée," Essais, Paris, J. Vrin, 1936, p. 139.

³ The best general work, both for its lucid presentation and its excellent bib liography of basic relevant sources and studies, on the context of scientific thinking against which Galileo's advances in dynamics took place, may be A. C. Crombie's Medieval and Modern Early Science, 2 vols., Garden City, New York, Doubleday, 1959 (originally Augustine to Galileo: The History of Science A. D. 400-1650, Cambridge, Harvard University Press, 1953). Specifically rele vant are: M. R. Cohen & I.E. Drabkin, A Source Book in Greek Science, New York, 1948; A. Mansion, Introduction à la physique aristotelicienne, 2nd ed., Louvain, 1946; M. Clagett, The Science of Mechanics in the Middle Ages, Madison, Wisconsin, 1959; J. A. Wiesheipl, The Development of Physical Theory in the Middle Ages, London, 1959.

⁴ "At present it is the purpose of our Author merely to investigate and to demonstrate some of the properties of accelerated motion, whatever the cause of acceleration may be…," Galilei, G., Discourses Concerning Two New Sciences, tr. Henry Crew and Alfonso de Salvio (Reprinted by arrangement with North-western University Studies in Great Books of the Western World, Ed. R. M. Hutchins, Vol. 28, 1952), p. 202.

⁵ For example, Galileo does not hesitate to advance a causal theory to explain the heat of a body as function of the motions and the impact on each other of constituent miniscule bodies. Cf. Galilei, G., The Assayer, in Discoveries and Opinions of Galileo, tr. Stillman Drake, New York, Doubleday, 1957, pp. 277-278.

⁶ Discourses Concerning Two New Sciences, p. 205.

⁷ Ibid., p. 206.

⁸ Ibid., p. 203.

⁹ Ibid., pp. 238-240.

¹⁰ The Republic, tr. G.M.A. Grube, Indianapolis, 1974, Bk. V, 273a, p. 132.