Des évolutionnismes sans mécanisme: les néo-lamarckismes métaphysiques d'Albert Vandel (1894-1980) et Pierre-Paul Grassé (1895-1985) [Evolution without a Mechanism: The Metaphysical neo-Lamarckisms of Albert Vandel (1894-1980) and Pierre-Paul Grassé (1895-1985)]

Albert Vandel and Pierre-Paul Grassé were influential and academically acclaimed zoologists in France in the second half of the 20th century. They were among the last scientific adversaries of Neo-Darwinism in France, proposing instead a form of Neo-Lamarckism up until the 1980s. Their theories were not equivalent but were both founded on the idea that evolution is internally driven, teleologically orientated but also « creative » in the sense that it generates unpredictable novelties. However, they proposed no alternative mechanism to replace natural selection. My analysis of their scientific, epistemological and metaphysical arguments shows that their take on evolution relied on cosmogonical and metaphysical explanations, founded on elements from Henri Bergson’s metaphysics of duration and Pierre Teilhard de Chardin’s theological cosmogony. Despite theoretical differences they shared ideas about mankind’s nature and destiny in the universe, which justified, in their view, their repudiation of Darwinian adaptation and chance as well as their philosophical vision of evolution.