Lionel Naccache is a former student of the Ecole Normale Supérieure de la Rue d’Ulm, a neurologist at the Salpétrière hospital, a researcher in neuroscience at ICM, a Professor of Medicine at Sorbonne University and a member of the French National Consultative Ethics Committee. His body of work is profoundly original, from the masterful Le Nouvel Inconscient to the bestseller Parlez-vous cerveau ? and is revolutionising our conception of subjectivity.

In this new essay, Lionel Naccache explores how we are part of the world, drawing on simple and timeless questions such as: what kind of relationship do we have with others? With the rest of nature? With ourselves over the course of our existence? In other words, what is our place in the universe?
If the world is defined as a whole in which each of us is an element, then there are two possible structures:
- A world as a continuous whole, in which each element is in direct continuity with all the others,
- Or a world as a discrete whole in the mathematical sense, in which each element can be individualised and isolated from all the others.
Lionel Naccache shows how we are permanently torn between these two forms of belonging, and that many contemporary questions can be broached using this discrete/continuous conceptual duo, outside the framework of mathematics, physics and metaphysics.
The aim is to formulate an ethic about our unique place in the world, applied to several contemporary issues (suicide, gender change, our relationship to the self (via an autobiographical section), wokeism and political ecology).