  Reid accepts that the qualities which we ordinarily conceive objects to have—whether shapes, sizes and motions, on the one hand, or colors, sounds, tastes and smells, on the other—are genuinely possessed by those objects (barring illusions and disorders of various sorts, which are, incidentally, difficult for any direct theory of perception like Reid's to explain). He thinks that shapes, sizes and motions are intrinsic properties of objects while colors, sounds, tastes and smells are relational properties of objects. But neither secondary nor primary qualities resemble the sensory experiences that they immediately cause in us. Colors, sounds, tastes and smells are powers to produce certain characteristic sensations in us in normal conditions. To believe that a rose has an agreeable smell or a red color is not to perceive any intrinsic qualities of the object, but is, rather, to perceive that the object bears a certain relation to something else—our minds. Reid writes,