Catherine Malabou: Plasticity of Reason

Chapter 4 examines the notion of plasticity which, derived from Hegel’s vocabulary, becomes the main characteristic of life from stem cells to the brain and artificial intelligence. If Ruyer distinguishes between preformationism and morphogenetic improvisation, Malabou contrasts the traditional notion of form with her notion of ‘plasticity’, which refers to qualitative change that takes place both at the level of cells (cell plasticity) and the brain (neuroplasticity), and which can be either creative or destructive. It is destructive plasticity that is the most interesting for neurological and philosophical investigations because it reveals the rupture between the cerebral and the mental, or between cerebral auto-affection and mental auto-affection. In these cases, we discover something that Malabou names as the ‘cerebral unconscious’ – cerebral activity without consciousness. These discoveries open a gap between the brain and the mind, or between the biological and the logical origin of thinking. Malabou argues that instead of being seen as the proprietor of the brain, the subject is defined by his or her neuronal connectivity, which relates the inside to the outside, the brain to the outside world.