How do we see non-luminous objects?

We see non-luminous objects because they reflect light that comes from luminous sources. Luminous objects, like the sun or a light bulb, emit their own light, which then bounces off non-luminous objects (such as a wall or a book) and travels to our eyes. This reflection allows us to perceive the shape, color, and features of those non-luminous objects in our environment.

The other methods mentioned do not relate to how we see objects. For instance, detecting heat does not provide visual information; it merely indicates temperature. Sound perception comes from vibrations in the air, which also does not contribute to sight. Sensations of vibrations aren’t associated with visual recognition either, as they pertain to our tactile or auditory senses rather than our vision. Thus, reflection of light from luminous objects is indeed the fundamental process that enables us to see non-luminous objects.