The discussion centers on the difficulty of imagining "unknown colors" compared to visualizing new objects, like cars. Participants explore why it's challenging to conceptualize colors that have never been seen, emphasizing that color perception is complex and not fully understood. It is noted that color is a measure of frequency, and our perception relies on the stimulation of cone cells in the eye. The inability to visualize unknown colors stems from a lack of reference points; unlike cars, which can be imagined using familiar shapes and materials, unknown colors lack any experiential basis. This leads to the conclusion that without prior experience or a frame of reference, imagining entirely new sensory experiences, such as colors outside our perception, is inherently difficult.