After the Dreyfus affair, which involved him personally because his second cousin Lucie was the wife of Dreyfus, Hadamard became politically active and a staunch supporter of Jewish causes[6] though he professed to be an atheist in his religion.[7][8]
Hadamard stayed in France at the beginning of the Second World War and escaped to southern France in 1940. The Vichy government permitted him to leave for the United States in 1941 and he obtained a visiting position at Columbia University in New York. He moved to London in 1944 and returned to France when the war ended in 1945.
Hadamard was awarded an honorary doctorate (LL.D.) by Yale University in October 1901, during celebrations for the bicentenary of the university.[10] He was awarded the CNRS Gold medal for his lifetime achievements in 1956. He died in Paris in 1963, aged ninety-seven.
In his book Psychology of Invention in the Mathematical Field,[11] Hadamard uses the results of introspection to study mathematical thought processes,[11]: 2 and tries to report and interpret observations, personal or gathered from other scholars engaged in the work of invention.[11]: 133 In sharp contrast to authors who identify language and cognition, he describes his own mathematical thinking as largely wordless, often accompanied by mental images that represent the entire solution to a problem. He surveyed 100 of the leading physicists of the day (approximately 1900), asking them how they did their work.
Hadamard described the process as having four steps of the five-step Graham Wallascreative process model, with the first three also having been put forth by Helmholtz:[11]: 56 Preparation, Incubation, Illumination, and Verification. [ Wallas' five stages added "Intimation" prior to Illumination, a sudden feeling of being about to find the solution to a problem. [12] ]
Publications
An Essay on the Psychology of Invention in the Mathematical Field. Princeton University Press, 1945;[13] new edition under the title The Mathematician's Mind: The Psychology of Invention in the Mathematical Field, 1996; ISBN0-691-02931-8, Online
Le problème de Cauchy et les équations aux dérivées partielles linéaires hyperboliques, Hermann 1932[14] (Lectures given at Yale, Eng. trans. Lectures on Cauchy's problem in linear partial differential equations, Yale University Press, Oxford University Press 1923, Reprint Dover 2003)
La série de Taylor et son prolongement analytique, 2nd edn., Gauthier-Villars 1926
La théorie des équations aux dérivées partielles, Peking, Editions Scientifiques, 1964
Leçons sur le calcul des variations, Vol. 1, Paris, Hermann 1910,[15]Online
Leçons sur la propagation des ondes et les équations de l'hydrodynamique, Paris, Hermann 1903,[16]Online
Four lectures on Mathematics, delivered at Columbia University 1911, Columbia University Press 1915[17] (1. The definition of solutions of linear partial differential equations by boundary conditions, 2. Contemporary researches in differential equations, integral equations and integro-differential equations, 3. Analysis Situs in connection with correspondences and differential equations, 4. Elementary solutions of partial differential equations and Greens functions), Online
Leçons de géométrie élémentaire, 2 vols., Paris, Colin, 1898,[18] 1906 (Eng. trans: Lessons in Geometry, American Mathematical Society 2008), Vol. 1, Vol. 2
Cours d'analyse professé à l'École polytechnique, 2 vols., Paris, Hermann 1925/27, 1930 (Vol. 1:[19]Compléments de calcul différentiel, intégrales simples et multiples, applications analytiques et géométriques, équations différentielles élémentaires, Vol. 2:[20]Potentiel, calcul des variations, fonctions analytiques, équations différentielles et aux dérivées partielles, calcul des probabilités)
Essai sur l'étude des fonctions données par leur développement de Taylor. Étude sur les propriétés des fonctions entières et en particulier d'une fonction considérée par Riemann, 1893, Online
Sur la distribution des zéros de la fonction et ses conséquences arithmétiques, Bulletin de la Société Mathématique de France, Vol. 24, 1896, pp. 199–220 Online
^Cartwright (1965), p. 731: "Hadamard recognised the danger of Hitlerism very early and, although a free thinker and anti-zionist, he was against all racial discrimination and worked to help the Jews in Germany in a more enlightened way than the Israelite Consistory and Zionist circles. With Paul Langevin he schemed to get a chair created for Einstein in France."
^Hadamard, Jacques (March 1988). Mandelbrot, Benoit B. (ed.). "How I did not discover relativity". The Mathematical Intelligencer. 10 (2). Translated by I. H. Rose. Springer: 65–67. doi:10.1007/BF03028360. S2CID122781052. p. 66: Hermite loved to direct to me remarks such as: 'He who strays from the paths traced by Providence crashes.' These were the words of a profoundly religious man, but an atheist like me understood them very well[.]
^Anand, Shafali R. (3 January 2012). "The Wallas Stage Model of Creativity". Retrieved 24 January 2024. The Wallas Stage Model of Creativity divides the process of creative thinking into 5 stages. These stages are Preparation, Incubation, Intimation, Illumination, and Verification.
Maz'ya, V. G.; Shaposhnikova, T. O. (1998). Jacques Hadamard: a universal mathematician. History of Mathematics. Vol. 14. American Mathematical Society/London Mathematical Society. ISBN0821819232.