This article is an analysis of a collection of articles published by Gilles Deleuze in 1953 under the direction of Georges Canguilhem. This collection, which has been little read and commented upon, sheds light on the intellectual trajectory of its author by underlining the theoretical hesitations that were his. I show that Deleuze then outlined an ambitious “psycho-sociological” project that he never fully realized. To do this, I reconstitute the psychological and ethological subtext of the book by following his sources; (...) I thus bring to light real theoretical positions often unnoticed in his work (in particular with respect to Henri Bergson, Jakob von Uexküll, and gestaltpsychology). I then argue that the difficulties linked to the theory of perception lead Deleuze to turn away from this project in order to devote himself to more specifically ontological problems. However, I suggest that these difficulties persist throughout Deleuze's works, where notions such as “sign” and “semiotics” both cover and avoid specifically perceptual problems. (shrink)

Neo-Darwinism, through the combination of natural selection and genetics, has made possible an explanation of adaptive phenomena that claims to be devoid of metaphysical presuppositions. What Bergson already deplored and what we explore in this paper is the implicit finalism of such evolutionary explanations, which turn living beings into closed and static systems rather than understanding biological evolution as a process characterized by its interactions and temporal openness. Without denying the heuristic efficiency of the explanation resting upon natural selection, we (...) analyze what it leaves out and what remains to be explored: the unpredictability of the evolutionary process. We will therefore study the role of contingency in evolution, as Stephen J. Gould proposed, but we will also consider the causality specific to the living world that makes it impossible to reduce it to a simple algorithm, as proposed by Daniel Dennett among others, but that it is really a creative causation, or dialectical spiral. (shrink)