The article examines, through the case studies of Georges Sorel (1847-1922) and Thomas Ernest Hulme (1883-1917), processes of politicization which Henri Bergson’s philosophy underwent in early 20th century Europe. It begins by outlining the paths that brought the two thinkers to read and endorse Bergson’s philosophy. Despite the fact that the former only really accepted the psychological arguments of the Données while the latter engaged much more with Bergson’s metaphysics, both were drawn to the French philosopher in virtue of the anti-determinist elements present in his thought. But when it came to bring this opposition to determinism to bear on political theory, their paths separated: whereas Sorel incorporated Bergsonian ideas in his revision of Marxism, Hulme found himself unable to erect a political theory on the basis of a metaphysics of flux. This significant difference is explained in generational terms. A Bergsonian cosmology of openness and transformation was seen as an excessively relativistic philosophical base for politics by Hulme because of the greater stakes that political commitment demanded from his generation – hence his conviction that politics could only be rooted in eternal, unchanging, absolutes.