This paper is concerned with the status of mathematical fictions in Leibniz’s work and especially with infinitary quantities as fictions. Thus, it is maintained that mathematical fictions constitute a kind of symbolic notion that implies various degrees of impossibility. With this framework, different kinds of notions of possibility and impossibility are proposed, reviewing the usual interpretation of both modal concepts, which appeals to the consistency property. Thus, three concepts of the possibility/impossibility pair are distinguished; they give rise, in turn, to (...) three concepts of mathematical fictions. Moreover, such a distinction is the base for the claim that infinitesimal quantities, as mathematical fictions, do not imply an absolute impossibility, resulting from self-contradiction, but a relative impossibility, founded on irrepresentability and on the fact that it does not conform to architectural principles. In conclusion, this “soft” impossibility of infinitesimals yields them, in Leibniz view, a presumptive or “conjectural” status. (shrink)

This paper argues for an interpretation of Leibniz’s claim that physics requires both mechanical and teleological principles as a view regarding the interpretation of physical theories. Granting that Leibniz’s fundamental ontology remains non-physical, or mentalistic, it argues that teleological principles nevertheless ground a realist commitment about mechanical descriptions of phenomena. The empirical results of the new sciences, according to Leibniz, have genuine truth conditions: there is a fact of the matter about the regularities observed in experience. Taking this stance, however, (...) requires bringing non-empirical reasons to bear upon mechanical causal claims. This paper first evaluates extant interpretations of Leibniz’s thesis that there are two realms in physics as describing parallel, self-sufficient sets of laws. It then examines Leibniz’s use of teleological principles to interpret scientific results in the context of his interventions in debates in seventeenth-century kinematic theory, and in the teaching of Copernicanism. Leibniz’s use of the principle of continuity and the principle of simplicity, for instance, reveal an underlying commitment to the truth-aptness, or approximate truth-aptness, of the new natural sciences. The paper concludes with a brief remark on the relation between metaphysics, theology, and physics in Leibniz. (shrink)

La position du problème Poser à nouveau la question du meilleur des mondes possibles chez Leibniz impose que l’on affronte une difficulté qui tient à l’expression elle-même. En effet, lui donner sa teneur conceptuelle requiert de notre part un effort complexe de détermination. Elle présuppose d’abord l’appréhension du caractère optimal de notre monde, ce qui est loin d’aller de soi. Mais surtout, il faut en outre, pour que...

La correspondance latine échangée entre Leibniz et Tun de ses maîtres, Jacob Thomasius, professeur de philosophie morale, puis de dialectique et d'éloquence à l'Université de Leipzig, figure dans l'Akademie-Ausgabe des œuvres de Leibniz. Richard Bodéüs nous en donne ici la premiére traduction intégrate en français, assortie d'analyses: celles-ci figurent dans I'introduction, dans les notes qui accompagnent le texte, et dans les commentaires qui suivent chaque piéce de la correspondance.