>And from thence it must follow, that not having a full sensation
      of the Object, we must be very lame and imperfect in our conceptions about
      it, and in all the propositions which we build upon it; hence we often take
      the shadow of things for the substance, small appearances for good similitudes,
      similitudes for definitions; and even many of those, which we think to be
      the most solid definitions, are rather expressions of our own misguided
      apprehensions then of the true na