Page:Mind (Old Series) Volume 12.djvu/357

344 W. JAMES Fig. 9. than the other. In Fig. 10, the retinal image of the space between the extreme dots is in all three lines the same, yet it seems much larger the moment it is filled up with other dots. Fig. 10. In the stereoscope certain pairs of lines which look single under ordinary circumstances immediately seem double when we add certain other lines to them. 1 (d) Ambiguous Import of Eye-movements. These facts show the indeterminateness of the space- import of various retinal impressions. Take now the eye's movements, and we find a similiar vacillation. When we follow a moving object with our gaze, the motion is ' voluntary ' ; when our eyes oscillate to and fro after we have made our- selves dizzy by spinning around, it is ' reflex ' ; and when the eyeball is pushed with the finger, it is ' passive '. Now, in all three of these cases we get a feeling from the move- ment as it effects itself. But the objective perceptions to which the feeling assists us are by no means the same. In the first case we may see a stationary field of view with one Volkmann, p. 253.