Le Collège à la Bibliothèque - Le vivant dévoilé. Avec Robert Hooke, Blaise Pascal

·1 hr 13 min·5 clips

Biologist Thomas Lecuy asks what the 'living' we study really is, when it seems both obvious and strangely hidden from investigation.

This episode is a recorded lecture from the 'Collège à la Bibliothèque' series, a collaboration between the Bibliothèque nationale de France and the Collège de France. Valérie Alagna, director of the Sciences and Techniques department, opens the event, noting the series' success since its 2019 launch. She introduces Stéphane Panara, a librarian who presents the guest speaker, biologist Thomas Lecuy. Lecuy is a specialist in morphogenesis, a former student of the École Normale Supérieure, and a professor at the Collège de France. The lecture centers on 'unveiling the living,' using four historical documents from the BnF's collections by Blaise Pascal, Robert Hooke, and Buffon. Lecuy begins by questioning the nature of the living, highlighting its functional organization, persistence despite cellular renewal, physiological adaptation, reproduction, and evolution. He then embarks on a historical journey, starting with the 17th-century metaphor of life as a machine, championed by Descartes, who saw organisms as passive structures governed solely by mechanical laws. This is contrasted with Leibniz's view of an intrinsic, active force within living matter. The core of the lecture examines the contributions of Hooke and Pascal. Hooke's 'Micrographia' (1665) is presented as a defense of empirical observation through microscopy, revealing a previously invisible microcosm and coining the term 'cell.' Pascal's 'Pensées,' written around the same time, offers a philosophical counterpoint, using imagination to contemplate human insignificance between the infinitely large and infinitely small. Lecuy argues both observation and imagination are essential for science. The narrative progresses through the history of microscopy, from Leeuwenhoek's observations of living cells to 19th-century cell theory and the discovery of chromosomes. It touches on the 17th-century debate between preformation (the idea of pre-existing miniature organisms) and epigenesis (progressive development of form). The lecture then shifts to the 20th century's molecular revolution, showing how techniques like electron microscopy allowed scientists to visualize processes like DNA replication and transcription, moving from imagined models to observed reality. A section on evolution discusses its 'invisible' nature due to vast timescales, highlighting the contributions of Lamarck and Darwin. Finally, Lecuy discusses the 'invisible' conceptual models needed to unify biological diversity, exemplified by Buffon's 18th-century theories of 'organic molecules,' 'penetrating forces,' and 'inner molds.' He concludes by quoting François Jacob, emphasizing that science explains the visible through the invisible, requiring both observation and imagination.

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