 Cavendish turns the debate on its head. In a nutshell, she argues that if elemental bodies do not exhibit an iota of mentality, then human brains would not exhibit an iota of mentality. But human brains do exhibit mentality. Therefore the smaller elemental bodies that compose the brain exhibit mentality as well. Those bodies that make up the brain have electrons and protons (although that language was not yet available in the Seventeenth Century); they also have a kind of proto-mentality and perception.