All the sensible qualities of matter are due to forces, gravitative, cohesive, propulsive, chemical, electrical, or to motions (like heat, sound, light, etc), or ‘motive forces’. Matter itself, therefore, is left as the unknown and unknowable substratum of force … It is not required to explain the appearance of anything we can experience, and is merely a metaphysical fiction designed to provide forces with a vehicle.
