The problem of explaining the experience of what I once called the unbounded visual world ( Gibson, 1950b, Ch. 8) or what I would now call the surrounding environment is a false problem. The retinal image is bounded, to be sure, and the foveal image has even smaller bounds, but the ambient array is unbounded. If the stimulation of the retina, or that of the fovea, is accepted as basic, another problem arises as well, how to explain the experience of a stable visual world. The stimulation of the retina is continually shifting, but this is also a false problem, for the structure of the ambient array is quite stable.
One sees the environment not just with the eyes but with the eyes in the head on the shoulders of a body that gets about. We look at details with the eyes, but we also look around with the mobile head, and we go-and-look with the mobile body.
A theory of how the eye-head system works has been formulated in this chapter. A theory of how the system works during locomotion was formulated in the last chapter. The exploratory adjustments of the eye-head system (fixation, saccadic movements, pursuit movements, convergence-divergence, and compensatory movements) are easier to understand. Even the optimizing adjustments of the lens, the pupil, and the photoreceptors are more intelligible when we consider optical information instead of stimuli.
The flow of optical stimulation is not a sequence of stimuli or a series of discrete snapshots. If it were, the sequence would have to be converted into a scene. The flow is sampled by the visual system. And the persistence of the environment together with the coexistence of its parts and the concurrence of its events are all perceived together.