Christian Leduc

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.

L’article vise à examiner les caractéristiques de la systématicité chez Johann Heinrich Lambert. Influencé par Christian Wolff, Lambert élabore une doctrine originale de l’architectonique qui comprend pour l’essentiel deux parties : d’une part, une manière de déterminer la représentation systématique dans la perception sensible qui constitue une première façon de connaître des rapports entre vérités. D’autre part, une théorie de l’harmonie réelle des vérités qui permet d’unifier des relations conceptuelles et propositionnelles et qui a comme avantages de mieux déceler les erreurs et de contrer le scepticisme. L’article a également pour objectif de montrer que la conception architectonique des vérités chez Lambert est certes fondationnaliste, mais ne saurait constituer une forme d’holisme.

In the Traité des systèmes, Condillac analyses a plurality of systematic metaphysical doctrines, specifically, those of Spinoza, Malebranche and Leibniz. Commentators have mainly interpreted this plurality as a way for Condillac to illustrate his criticisms and to raise doubts about the main contemporary systems while using the same criteria for interpretation. However, I note that his analytic tools differ according to which philosopher or philosophical system he analyses. This paper focuses on the criticism of Leibniz’s system, and aims to show that Condillac operated from subsequent reconstructions. In order to raise criticisms against the Leibnizian system, Condillac gave it an architectonic structure that is borrowed mainly from Wolff.

In this paper, I show that Maupertuis and Euler offer a contrasting conception of metaphysics of nature. It consists mainly for them in repositioning cosmology in relation to natural sciences. Instead of considering metaphysics to be at the foundation of scientific theories, as was assumed by Descartes, Wolff, and, in a certain way, Kant, or simply prohibiting the very idea of a cosmology, as d’Alembert would stipulate at the same period, Maupertuis and Euler invert the order of disciplines to give priority to physical sciences over metaphysics. This repositioning leads of course to several questions : first, how does scientific theories validate or deny metaphysical principles? Even more important, which role falls to metaphysics of nature given that sciences not only possess a theoretical autonomy, but also a priority over ontological reflections? Besides, it seems that metaphysics would be reduced, for these two philosophers, to the realm of cosmology alone, in particular to questions concerning force and the principle of least action, the ontological status of space and time, and the first constituents of matter, such as extension, inertia, impenetrability, and motion.

Le principe de l’identité des indiscernables constitue l’un des aspects essentiels de la métaphysique leibnizienne de la substance. Il implique notamment que toute substance s’individualise par la totalité infinie de ses propriétés. Sur le plan épistémologique, ce principe pose toutefois problème: comment un entendement fini parvient-il à se représenter les individus, sachant que seul l’entendement de Dieu possède la capacité de connaître la série infinie des propriétés qui individualise la substance? L’auteur vise ici un double objectif : d’une part, démontrer qu’il existe chez Leibniz une philosophie de la connaissance suffisamment distincte des autres disciplines, notamment de la logique et de la métaphysique. D’autre part, examiner l’impact de cette épistémologie sur la théorie de l’individuation. Il s’agit d’analyser les différents moyens employés par Leibniz pour expliquer la conception des êtres individuels du point de vue de la représentation humaine.

Christian Leduc | : Dans le présent article, je montre que Maupertuis et Euler proposent une conception contrastée de la métaphysique de la nature. Il s’agit principalement pour eux de repositionner la cosmologie par rapport aux sciences de la nature. Au lieu de considérer la métaphysique comme étant au fondement des théories scientifiques, comme le supposent Descartes, Wolff et, d’une certaine manière, Kant, ou simplement d’interdire l’idée même d’une cosmologie, comme le stipulerait à la même époque d’Alembert, Maupertuis et Euler, renversent l’ordre des disciplines pour donner aux sciences physiques une primauté sur la métaphysique. Ce repositionnement entraîne évidemment plusieurs questions : d’abord, de quelle manière les théories scientifiques peuvent-elles valider ou infirmer un principe métaphysique? Plus important encore, quel rôle incombe à la métaphysique de la nature, étant donné que les sciences possèdent non seulement une autonomie théorique, mais même une priorité sur les réflexions ontologiques. Il semblerait d’ailleurs que la métaphysique se réduise, pour ces deux philosophes, au seul domaine du cosmologique, en particulier aux questions qui concernent la force et le principe de moindre action, au statut ontologique de l’espace et du temps et aux déterminations de la matière que sont l’étendue, l’inertie, l’impénétrabilité et le mouvement. | : In this paper, I show that Maupertuis and Euler offer a contrasting conception of metaphysics of nature. It consists mainly for them in repositioning cosmology in relation to natural sciences. Instead of considering metaphysics to be at the foundation of scientific theories, as was assumed by Descartes, Wolff, and, in a certain way, Kant, or simply prohibiting the very idea of a cosmology, as d’Alembert would stipulate at the same period, Maupertuis and Euler invert the order of disciplines to give priority to physical sciences over metaphysics. This repositioning leads of course to several questions : first, how does scientific theories validate or deny metaphysical principles? Even more important, which role falls to metaphysics of nature given that sciences not only possess a theoretical autonomy, but also a priority over ontological reflections? Besides, it seems that metaphysics would be reduced, for these two philosophers, to the realm of cosmology alone, in particular to questions concerning force and the principle of least action, the ontological status of space and time, and the first constituents of matter, such as extension, inertia, impenetrability, and motion

The Dissertatio praeliminaris is one of the early works of Leibniz in which he proposes an elaborate critique, while presenting his own principles. In accepting several points of Nizolius's philosophy, the young Leibniz tries moreover to defend theses which have constituted the basis of many of his later theories. Three major topics will be examined in this article. First, the question of definition, which is taken from a grammar point of view, where clarity is, in fact, the only criterion to establish the signification of words in usage. Second, perhaps the most important, concerns the problem of nominalism that puts Nizolius in opposition with Leibniz: they do not agree on the determination of signification, meaning whether it stands on conventions or on mental concepts. Third, the link between demonstration and induction as a consequence of a nominalistic approach is also discussed in Leibniz's preface. We are thus better able to understand the origins of Leibniz's philosophical reflection

Leibniz’s universal characteristic is a fundamental aspect of his theory of cognition. Without symbols or characters it would be difficult for the human mind to define several concepts and to achieve many demonstrations. In most disciplines, and particularly in mathematics, the mind must then focus on symbols and their combinatorial rules rather than on mental contents. For Leibniz, mental perception is most of the time too confused for attaining distinct notions and valid deductions. In this paper, I argue that the functions of symbolization differ depending upon the kind of concepts that are replaced with characters. In my view, most commentators did not sufficiently underline the distinction between two main functions of formal substitution in Leibniz’s characteristic: either increasing our knowledge or simply structuring it. In the first case, we complete our knowledge because formal substitution makes sensible and imaginary concepts more distinct. In the second case, symbolization helps to organize contents that are already conceived of by reason. Thus the process of substitution is not always identically applicable, for symbols replace different types of concepts

This paper discusses the problem of sensible qualities, an important, but underestimated topic in Leibniz's epistemology. In the first section, the confused character of sensible ideas is considered. Produced by the sensation alone, ideas of sensible qualities cannot be part of distinct descriptions of bodies. This is why Leibniz proposes to resolve sensible qualities by means of primary or mechanical qualities, a thesis which is analysed in the second section. Here, I discuss his conception of nominal definitions as distinct empirical representations. The provisional and modifiable status of nominal definitions is then explained in the third section. Since nominal descriptions always contain sensible determinations, Leibniz claims that empirical knowledge is indefinitely changeable according to progress in sciences. In the final section, I address the criterion of coherence that enables us to approve of hypotheses that are based on both sensible and empirical properties