 (1) Early modern natural philosophers agree with their Scholastic opponents in granting that matter is utterly passive and devoid of efficacious causal powers. Sturm takes stock of this point, joining Descartes and other Cartesians in defining matter in terms of pure extension (res extensa) and motion as local motion. However, early modern natural philosophers disagreed with Scholastics and among themselves about the notion of ‘form’, whether there could be any ‘substantial form’ and if rejecting substantial forms would lead to discard all causal powers in finite beings.