that the subject of movement can be indeterminate (as when we see, in stroboscopic presentation, a triangle moving towards a circle and being transformed into it), that the object in motion has no need to be posited by an act of explicit perception, that it is merely a 'co target' or 'coapprehension' in the perception of movement, that it is seen only as the backs of objects or the space behind me are seen, and that finally the identity of the moving object, like the unity of the thing perceived, is apprehended through a categorical perception (Husserl) in which the category is operative without being conceived for itself.