section_path: History of the concept/Momentum/Gottfried Leibniz
section_name: Gottfried Leibniz
paragraph_text: Gottfried Leibniz
  
  In 1686, Gottfried Wilhelm Leibniz, in Discourse on Metaphysics, gave an argument against Descartes' construction of the conservation of the "quantity of motion" using an example of dropping blocks of different sizes different distances. He points out that force is conserved but quantity of motion, construed as the product of size and speed of an object, is not conserved.