> It seems to me that before Newton, people only had a vague notion of what a force is. > When Newton stated that F=ma, he defined the concept of force precisel

> It seems to me that before Newton, people only had a vague notion of what a force is. > When Newton stated that F=ma, he defined the concept of force precisely. Newton wasn't the first to define the concept of force, nor the first to formulate the basic laws of motion. E.g. Galilei had formulated both the first and second laws in some sense, restricted to cases such as straight line motion on a plane. The laws came out of experiments. Newton's brilliant work was in collecting the three laws, generalizing them and realizing their combination applied to celestial mechanics as well as the mundane brick sliding down a plane.