Final answer:
A completely black object would be visible in light due to contrast with its surroundings, but details may be hard to discern. Its visibility depends on light reflection, and in complete darkness, it would be indistinguishable from the surroundings. Blackbody radiation also affects its appearance; as temperature increases, it may emit visible light and no longer appear black.
Step-by-step explanation:
If an object were completely black, it would not emit or reflect any light and would thus appear black in color. However, whether you can see it directly would depend on the context. If the object is outlined against a background that is lighter, or if there is light being reflected off other objects onto it, then your eyes would see the shape of the object due to the contrast with its surroundings. In complete darkness, without any light source, it would be indistinguishable from the surroundings and thus, invisible to the human eye. Our ability to see depends on the reflection of light. A perfectly black object observed in the light would still be visible due to the light reflected off surrounding surfaces, but its details may be hard to discern.
Visual perception relies on the way our rods and cones process light; this plays a significant role when transitioning from a brightly lit environment to a darker one, as per the Take-Home Experiment. This aligns with Socrates's observation about vision in dim light. In terms of blackbody radiation, as the temperature of a black object increases, it will begin to emit radiation in the visible spectrum and therefore may no longer appear black; it might even glow if its temperature is high enough, as described in the Conceptual Questions section relating to an object's temperature rising from 1000 K to 1,000,000 K.