Christian Leduc

The importance of teleology in the 18 th century has mainly been studied from the point of view of a few specific authors. Leibniz is one of the most convinced advocates of the use of final causes in both physics and metaphysics. Despite its significance for the history of teleology, very few studies were in fact devoted to the influence of the Leibnizian doctrine during the 18 th century. However, Leibniz’s reception allows us not only to understand his own views on teleology in comparison with those that 18 th century thinkers attributed to him, but also to feed the conceptual debate on the legitimate articulation of finality and efficiency in natural philosophy in that period. Consequently, studies on 18 th century physico-theology may help us to clarify the following questions: what is the difference between explanations concerning organic functions and in the architectonic use of the principle of optimum in physics? And how exactly do “the details of physics” illustrate the general harmony of the world? In order to clarify these kinds of questions, the present issue explores how Leibniz’s 18 th century readers integrated in their own philosophical doctrines multiple interpretative possibilities opened up by Leibniz’s texts.

The paper aims at analyzing Lambert’s conception of empirical knowledge that is part of scientific learning. Indeed, in the Neues Organon, he claims that science is obtained with the help of both a priori and a posteriori knowledge. Lambert’s originality lies on the application of the analytic and synthetic methods of reasoning, which are traditionally used in formal disciplines, to the realm of experience. Transforming common knowledge into scientific a posteriori knowledge is mainly based on the employment of such demonstrative methods. This allows Lambert to introduce some important theoretical tools in his theory of experience, in particular about the search for the conditions of observations and experimentations as well as the establishment of hypothesis. For Lambert, the synthetic method in empirical deductions requires the use of conjectures and probable principles.

The article examines how Reimarus reorients concepts borrowed from Leibniz and Wolff – the principles of perfection, harmony and continuity – in order to feed his own natural religion project. Teleology is understood as a doctrine aiming at proving not only God’s perfections, but also the effects of the divine wisdom on creatures. Consequently, recourse to final causes in natural philosophy cannot remain at the level of general reasons, as Maupertuis’s principle of least action does, but rather ought to be used in the explanation of the specific purpose of beings.

Ce livre s’intéresse à une rencontre : celle de deux philosophes, mais aussi celle de deux siècles et de deux régimes de pensée. Leibniz (1646-1716) et Diderot (1713-1784) appartiennent à deux traditions en apparence opposées : on associe généralement la pensée leibnizienne aux grands systèmes métaphysiques du XVIIe siècle, et celle de Diderot à la mise en pièces de ces édifices par la voie d’une philosophie expérimentale radicalement antisystématique. Pourtant, plusieurs liens entre les deux œuvres sont visibles, qu’il s’agisse d’emprunts conceptuels ou thématiques par Diderot ou de convergences plus difficiles à circonscrire. Le premier objet de ce livre est d’identifier ces liens et de faire le point sur cette sympathie entre les deux philosophies. Mais ce livre s’intéresse aussi à cette rencontre pour ses effets transformateurs, tant sur le plan des concepts, des thèses et des arguments que sur celui des méthodes. Il s’agit alors de voir comment la rencontre avec le leibnizianisme a nourri la pensée diderotienne, comment la lecture du texte leibnizien par Diderot en modifie le sens, comment elle peut parfois en être une interprétation ou un devenir possible. Pour saisir ces transformations, les auteurs ont examiné divers contextes théoriques dans lesquels les pensées de Leibniz et Diderot dialoguent : métaphysique et philosophie de la nature, épistémologie et philosophie des sciences, théorie de la perception et esthétique. À travers ce dialogue, l’ouvrage contribue à une réflexion générale sur les méthodes requises pour mettre en perspective les rapports entre des philosophies à la fois proches et éloignées.