The PHILIUMM Project aims to reassess the thought of the philosopher and mathematician Gottfried Wilhelm Leibniz (1646-1716) through a systematic exploration of his unpublished mathematical manuscripts. As he himself stressed on several occasions, these two facets of his work were closely linked. Yet half of his mathematical output is still completely unpublished. As for the half that has been published, much of it has not been edited according to rigorous scientific standards (to the point where we sometimes read texts invented by the editors).

The project is based on a research group that has developed over the last ten years in France, and is now without equivalent anywhere in the world. It also relies on a close partnership with the Leibniz-Archiv in Hanover, and benefits from recent advances in the digitization of Leibniz's mathematical manuscripts (accessible online since 2016). Preliminary results have already been obtained on specific sets of texts (mainly on algebra and geometry: mathesis.altervista.org). We have identified original scientific hypotheses to guide the study of nearly 17,000 pages of unpublished material.

The main hypothesis is a radical reinterpretation of what it meant for Leibniz to reduce mathematical truths to "identities". This hypothesis has strong echoes in current philosophy of logic and mathematics, and will hopefully shed new light on contemporary debates. We also hope to use this project to make Leibniz's thought more accessible (especially to historians of mathematics, mathematics teachers and students) by publishing editions of texts online and developing new digital tools for exploring them.

The project is divided into five tasks corresponding to the following themes: Dyadica (binary arithmetic), Ars combinatoria, Foundations of differential calculus, Doctrine of mathematical abstraction, Machines and formal thought.