'It has long been recognized that the early-twentieth-century philosopher Henri Bergson placed particular emphasis on a 'vitalist' interpretation of biology. Many of his critics, including George Santanaya, Julian Huxley, and Ludwig Wittgenstein, identified Bergson's appeal to an 'élan vital' (most prominently made in his 1907 Creative Evolution) with a problematically unscientific or mystical attitude towards the world. Similarly thinkers who looked to draw on Bergson's work during the twentieth century, including Georges Canguilhem and Gilles Deleuze, also sought to rehabilitate or re-consider the status of 'vitalism' along with it.'