Gratitude to the Ecole Normale Superieure PSL faculty.

Thank you for directing the rue d'Ulm as a philosopher of care would, with attention to each student as a person, and for keeping Bergson and the whole living tradition of French philosophy in conversation with the present.

Thank you for following the world's hidden wealth into the tax havens where it hides, for founding the EU Tax Observatory, and for giving democracies the numbers they need to debate taxation honestly.

Thank you for making the physics of glass, that most stubborn of unsolved problems, yield real answers, and for showing that the same statistical physics illuminates ecosystems and the deep networks reshaping our world.

Thank you for wrestling honestly with the Navier-Stokes equations, the mathematics hiding inside every breath of wind, and for leading and teaching in the DMA with a generosity that young analysts remember.

Thank you for tracing the ocean's quiet labor of absorbing our carbon, for carrying that science into the IPCC reports the world negotiates by, and for leading ENS geosciences with the sea always in view.

Thank you for sailing the world's oceans with Tara to sequence the invisible plankton that make every second breath we take, and for making the diatom a window onto how the living ocean works.

Thank you for giving machine learning its mathematical conscience: proofs of when and why our algorithms work, taught and shared so openly that half the field learned optimization from your notes.

Thank you for pursuing the cognitive and genetic roots of dyslexia and language disorders with rigor, and for defending evidence about how children actually learn in a public square that badly needs it.

Thank you for revealing how the ear of a newborn tunes itself to the sounds of its mother tongue, and for years of quiet leadership at the LSCP that made Paris a world capital of psycholinguistics.

Thank you for keeping philosophy answerable to the hardest questions of our time, violence, language and living together, and for the years you led the rue d'Ulm's philosophy department as a place of open argument.

Thank you for trapping single photons between mirrors at the Kastler Brossel laboratory and watching quantum mechanics unfold one jump at a time, work that earned the Nobel Prize and taught the world that the quantum can be tamed.

Thank you for the Lundis de la philosophie and for a lifetime of asking, with Aristotle at your side, what a human being is, and for writing philosophy clear enough that anyone who wonders can follow.