Pierre-Olivier Méthot

Université Laval


Pierre-Olivier Méthot is Full Professor in the Faculty of Philosophy at Laval University (Quebec City) where he is also the holder of the Canada Research Chair in Medical Humanities and History of Biological Thought. His teaching and research interests are in the history and philosophy of the life sciences and medicine. He has edited several books and journal issues on major figures in French thought, including Georges Canguilhem, François Jacob, and Mirko Grmek, as well as on the history of infectious diseases in the 20th and 21st century. He serves an Associate Editor for History and Philosophy of the Life Sciences since 2020 and he is the Director of Undergraduate Studies in the Faculty of Philosophy. He is now completing the final volume of Canguilhem's Complete Works (with Camille Limoges).



"Stanley Falkow and the Molecular Study of Koch’s Postulates: Philosophical and Historical Perspectives on Pathogenic Organisms"

Medical bacteriologist Stanley Falkow (1934-2018) liked to describe himself as being ‘on the side of the microbes’. Standing between the clinic and the laboratory, Falkow comes from a generation of scientists who trained and worked in the tradition of classical microbiology. Falkow, however, graduated at a time when the nature of the gene had been identified and when molecular biology was in full swing; as a consequence, he was ready to expand this novel approach to understand the mechanisms that make specific bacteria pathogenic or commensal organisms. In the 60s and 70s, his study of antibiotic resistance factors led him to investigate how some harmless microorganisms can turn pathogenic – sometimes very quickly. Following his training in bacteriology, Falkow saw himself as a ‘microbe hunter’ – like the famous figures once described by Paul de Kruif (1926) – and trained in his turn new generations of scientists in molecular microbial pathogenesis at the University of Georgetown, Washington and Stanford. Falkow’s scientific legacy includes some of the first studies of the spread of disease resistance and a new tool to characterize the nature of organisms: the ‘Molecular Koch’s Postulates’. After placing his discovery of the transmission of resistance factors in a longer historical perspective, this talk will examine his research on the mechanisms that enable microbes to undergo biological changes and impact health, and how Falkow pursued in parallel a long-standing conceptual question as part of his scientific investigation, namely: ‘what is a pathogen?’ Falkow’s work, I argue, provides a unique window into how medical scientists grappled with new emerging threats in the microbial world at a time when many considered that the conquest of infectious diseases was well underway. In conclusion, I will reflect on the classification of pathogenic organisms and on the future of the ‘Molecular Koch’s Postulates’ in the 21st century.