— 545 —
Because all connexion between any secondary and primary Qualities is undiscoverable.
      §12. Besides this Ignorance of the primary Qualities of the in-
sensible Parts of Bodies, on which depend all their secondary
Qualities, there is yet another and more incurable part of Ignorance,
which sets us more remote from a certain Knowledge of the Co-
existence, or Inco-existence (if I may so say) of different Ideas in the
same Subject; and that is, that there is no discoverable connection
between any secondary Quality, and those primary Qualities that it
depends on.
Locke Hum IV, 3, §12, p. 545