Thomas Reid,
An Inquiry into the Human Mind…
“ Let us next consider hardness and softness; by which words we always understand real properties or qualities of bodies of which we have a distinct conception.When the parts of a body adhere so firmly that it cannot easily be made to change its figure, we call it hard; when its parts are easily displaced, we call it soft. This is the notion which all mankind have of hardness and softness: they are neither sensations, nor like any sensation ”
