Only after the atom has lost the last sensible quality does its true meaning for the physical world view become clear; the unity — real, though remote from our immediate perception — of all that our perception knows only as a multitude of appearances is systematically held together and symbolically represented in it, but not mechanically explained.
Translated by Majorie Grene - The World View of Physics - Chapter Two (pp. 55-56), Routledge & Kegan Paul. 1952