He proved this to The Royal Academy by having Wrenn stand at the bottom of the Pizza Tower and dropping first a 100 kilos of feathers and cotton. They both hit at the same time. Then 100 kilos of iron cannon balls and an anvil. Wrenn was convinced that all bodies fall at the same speed. Kepler thought planets were attracted to the sun by magnetic force.
Movement is porportional to mass and distance.
For every action there is an equal and opposite reaction. Then came Albert IQ Einstien. This means there are universal laws that are the same throughout the universe. All 3 Newton laws. I know they will play the semantics game.