Final answer:
The brain cannot distinguish reflections separately at the limit of temporal resolution or the fusion threshold of the visual system. This is related to the interplay of retinal disparity and the active processing done by our visual system to perceive depth and a coherent view of the world despite various perceptual challenges.
Step-by-step explanation:
The point in time, when the brain cannot discern reflections separately because they are so tightly spaced, is known as the limit of temporal resolution or the fusion threshold of the human visual system. This phenomenon is related to the concept of retinal disparity and depth perception, which arise from the interocular distance—the small separation between our eyes. The significance of this spacing is that it enables each eye to receive slightly different visual information, which the brain then combines to produce a three-dimensional perception of the world. When objects are very close to one another or when their reflections occur in quick succession, the visual signals become hard to separate, resulting in an inability to perceive them as distinct. This limit can be influenced by various factors, including the severity of atmospheric aberrations. In Bruce's case, as referenced in the background information, it implies that despite a possible lack of binocular vision for much of his life, he had a moment of binocular activation early in development that allowed those cells responsible for depth perception to survive.
In essence, our visual system works not by simply capturing images like a camera, but by processing visual stimuli actively to create a coherent representation of the environment, taking into account factors like color constancy, edge detection, and shadows that affect our perception.