Primary Qualities (Galileo)

Galileo’s first argument for the existence of primary qualities 1 is a purely rational one. He asks himself what properties must a thing have in order to exist? and concludes that only extension , shape , size , position (in space, time and relative to other bodies), motion and number Keith Wilson In his Assayer of 1623, Galileo explained his notion of the difference between those qualities, mostly found by touch, that are inherent in bodies (weight, roughness, smoothness, etc.) and those that are in the mind of the observer (taste, color, etc.)--in other words, the difference between what we call primary and secondary qualities The Galileo Project: