Final answer:
The image on the retina is ambiguous because a given arrangement of light could be produced by various object configurations, despite being a real image where light rays cross at a single point.
Step-by-step explanation:
When we consider that a particular image on the retina can be created by many different objects in the environment, it is easy to see why we say that the image on the retina is ambiguous. The reason behind this is due to the way light rays work. Light rays from every part of an object pass through every part of the eye's lens to form a final image on the retina. This process creates what is known as a real image, which means that light rays from a single point on the object actually cross at the location of the image and can be projected onto a surface, such as a screen, film, or the retina of an eye. However, because any given arrangement of light on the retina can be produced by many different configurations of objects, the image is fundamentally ambiguous without additional visual cues and context.