distinguish), he also acknowledged the influence of Plato and George Berkeley (both of whom he saw as important precursors of, or influences on, pragmatism), Gottfried Leibniz, Victoria Welby-Gregory, G.E. Moore, Bertrand Russell, Peano, and Franz Brentano. He corresponded with many of his contemporaries. His early work included papers on symbolic logic, focusing on its rôle in philosophy, and distinguishing between logic and psychology and epistemology. History of science Vailata's main historical interests concerned mechanics, logic, and geometry, and he was an important contributor to a number of areas, including the study of post-Aristotelian Greek mechanics, of Galileo's predecessors, of the notion and rôle of definition in the work of Plato and Euclid, of mathematical influences on logic and epistemology, and of the non-Euclidean geometry of Gerolamo Saccheri. He was particularly interested in the ways in which what might be seen as the same problems are addressed and dealt with at different times. His historical work was interrelated with his philosophical work, involving the same fundamental views and methodology. Vailati saw the two as differing in approach rather than subject matter, and believed that there should be co-operation between philosophers and scientists in the pursuit of historical studies. He also held that a complete history demanded that one take into account the relevant social background. Of a certain interest is the participation of Vailati in the scientific activity of the chair of "Calculus infinitesimal" held by Giuseppe Peano. We are in Turin in 1892. The period is full of Prolusions and there are the emergence of disciplines such as anthropology and sociology, which have produced a new scientific concept in the nineteenth century. The Turin Prolusions (1896-1898) open the horizon to new discoveries and to the formulations of scientific theories and hypotheses concerning the relationship between science and its history. In this context there is the "questions of words", which concern language and its functioning as a means of transmitting ideas. The superseding of scientific theories and other results doesn't involve their destruction, for their importance is increased by their being superseded: "Every error shows us a rock to be avoided, while not every discovery shows us a path to be followed. See also Separation relation Notes Sources Giovanni Vailati (1972) Scritti filosofici. Ivor Grattan-Guinness (2000) The Search for Mathematical Roots 1870–1940, Princeton University Press. Ferruccio Rossi-Landi (1967) "Giovanni Vailati", in The Encyclopedia of Philosophy", ed. Paul Edwards. Collier Macmillan C.