Second, attempting a saccade when the eyes are paralyzed or otherwise immobilized results in an apparent shift of the visual scene in the same direction (Helmholtz 2005 [1924]: 205–06; Mach 1897 [1886]: 59–60). This finding would make sense if efferent signals to the eye are used to determine the direction of gaze: the visual system “infers” that perceived objects are moving because they would have to be in order for retinal stimulation to remain constant despite the change in eye direction predicted on the basis of motor outflow.