 We are farther to consider concerning Perception, that the Ideas we receive by sensation, are often in grown People alter’d by the Judgment, without our taking notice of it. When we set before our Eyes a round Globe, of any uniform colour, v.g. Gold, Alabaster, or Jet, ’tis certain, that the Idea thereby imprinted in our Mind, is of a flat Circle variously shadow’d, with several degrees of Light and Brightness coming to our Eyes. But we having by use been accustomed to perceive, what kind of appearance convex Bodies are wont to make in us; what alterations are made in the reflections of Light, by the difference of the sensible Figures of Bodies, the Judgment presently, by an habitual custom, alters the Appearances into their Causes: So that from that, which truly is variety of shadow or colour, collecting the Figure, it makes it pass for a mark of Figure, and frames to it self the perception of a convex Figure, and an uniform Colour; when the Idea we receive from thence, is only a Plain variously colour’d, as is evident in Painting.